JP4137067B2 - Image processing method and apparatus - Google Patents

Description

  The present invention relates to an image processing method and apparatus for improving edge jaggies with respect to an image subjected to pseudo halftone processing.

  Conventionally, several techniques for improving jaggy generated in a low resolution printer have been proposed. The jaggy here refers to rattling that occurs at the edge of a character. An example of this is shown in FIG. Although there are a plurality of cells in the figure, each one corresponds to one pixel, which is 300 dpi in FIG. When the image resolution is as low as 300 dpi as shown in FIG. 18, jaggy occurs particularly at the edge portion of the oblique contour.

  In contrast to such jaggies, in the conventional technique, pattern matching is performed to add image data to a portion that matches the pattern or remove pixels that cause jaggy, thereby improving jaggy. Since the details of the pattern matching here are known techniques, detailed description thereof is omitted. Patent Document 1 discloses an example of a smoothing technique.

FIG. 19 shows an example in which the jaggy is improved. (A) in FIG. 19 shows a state in which halftone data is added to pixels matched by pattern matching. Halftone data is added to the location where the jaggy is generated. Particularly in a printer having an electrophotographic process, there is an effect that the image quality can be greatly improved only by adding such halftone data to the jaggy.
On the other hand, (b) of FIG. 19 shows a state in which pixel-divided data is added to pixels matched by pattern matching. In the above example, the pixel division is a technique in which one pixel of 300 dpi is divided into a plurality of portions and dots are partially formed. Here, two divisions are shown as an example. Since the technique of pixel division is also known, detailed description thereof is omitted here.

  The above-described prior art adds halftone dots or pixel division dots to the jaggy, but conversely changes full dots to half dots or full dots to pixel division dots. In some cases, such a process of thinning the pixels of the jaggy portion is performed, and the above-described jaggy is improved by combining such processes.

  However, such a method has a problem as shown in FIG. That is, when pseudo halftone processing such as screen processing is performed on a halftone character as shown in FIG. 20A, the result is as shown in FIG. That is, in the case of halftone characters, the pseudo halftone process is performed at a screen resolution that is coarser than the printer resolution of 300 dpi, so that characters and fine lines are cut off. This is because the screen resolution is represented in a pseudo manner by collecting a plurality of pixels (dots) of the printer, so that the pseudo halftone process is not performed using a screen resolution higher than the resolution of the printer. For example, the normal screen resolution (number of lines) is 133 lines to 175 lines, at most about 268 lines. This is because when the number of lines is higher than this, a stable image quality cannot be obtained due to the characteristics of the electrophotographic printer. As a result, there has been a problem that jaggy cannot be improved by the above-described smoothing by pattern matching.

  On the other hand, as apparent from FIG. 21 showing a part of characters seen in a macro, the jaggy part in question may appear at the edge part of the image obtained by performing the screen processing on the halftone image. Thus, not only the above-mentioned jaggy due to the printer resolution but also the low line-number jaggy generated in the screen processing becomes a problem.

  In addition, when smoothing processing is performed on an image that has been subjected to lossy compression such as JPEG, the mosquito noise generated by deterioration due to compression (the compression rate of lossy compression is increased and the file capacity is increased). When noise is reduced, noise generated in images and edges that contain high-frequency components, which are commonly used as mosquito noise in the image processing technology field because mosquito swarms appear to cling to the edges. There is also a problem that the smoothing process is not executed because the image and the pattern to be matched by the pattern matching process do not match. In this case, of course, a sufficient smoothing effect cannot be obtained.

  On the other hand, when the processing for adding dots to improve jaggy as described above is performed on, for example, lower case letters of 3 points or less, or fine lines of 1 dot or 2 dots, there is a disadvantage. For example, it is a phenomenon in which lowercase letters are crushed or bumps like a lump are formed in the jaggy part of diagonal thin lines.

As a technique for solving the above problem, Patent Document 2 is cited. However, since Patent Document 2 is intended to improve jaggies of a binary image converted from a multi-value image by error diffusion processing or the like, However, a sufficient effect cannot be obtained. Furthermore, it has been pointed out that it is difficult to cope with various image forming processes since the image of the error diffusion processing system is targeted.
JP-A-4-341060 JP 10-42141 A

In view of the above-described conventional problems, the present invention improves jaggies on various pseudo-halftone processed images that are not multi-level images and images of an error diffusion processing system, and is a negative effect due to jaggy improvement processing. Provided are an image processing method and an apparatus that eliminate the phenomenon that lowercase letters are crushed or that a lump-like lump is formed in a jaggy portion of an oblique thin line.

  Therefore, in the present invention, the above problem has been solved by the following configuration. Specifically, the following configuration is provided.

The image processing apparatus of the present invention inputs multi-value image data , processed image data obtained by performing pseudo halftone processing on the multi-value image data, and attribute data of the multi-value image data, and includes an outline portion of the processed image data. an image processing apparatus having an image processing circuit configured to correct, said image processing circuitry, based on said multi-value image attribute data indicating an attribute of the image data and the image data of the target pixel data, the Control means for controlling whether or not to correct pixels in the contour portion of the processed image data, and contour portion correcting means for correcting the contour portion of the processed image data based on the control of the control means , the attribute data includes data indicating the size of the object that contains the image data of the target pixel of the multivalued image data, the control means, the processed image data in consideration of the size of the object And controlling whether to perform the correction of the pixel of the contour portion.

Here, the attribute data includes data indicating that the target pixel of the multi-valued image data is included in a thin or small object. The attribute data includes data indicating that the pixel of interest of the multi-valued image data is included in a line, graphic, or character object. Further, the control means corresponds to the contour detection data generated based on the image data of the target pixel of the multi-valued image data and the attribute data indicating the attribute of the image data by the contour correction means. Whether or not to correct the partial pixels is controlled. Further, the contour correction means is a first contour correction means for detecting and correcting the contour based on the pixel arrangement of the contour detection data in the first state, and a second state different from the first state. Second contour correction means for detecting and correcting the contour based on the pixel arrangement of the contour detection data, and the control means is configured to detect the first when the contour detection data is in the first state. The contour correction unit is selected, and the second contour correction unit is selected when the contour detection data is in the second state. Further, when the attribute data indicates that the target pixel of the multi-valued image data is included in a thin or small object, the control unit avoids the correction of the contour portion by the contour portion correcting unit. Further, the control means avoids detection of a contour portion by the contour portion correcting means.

The image processing circuit of the present invention inputs multi-value image data , processed image data obtained by performing pseudo halftone processing on the multi-value image data, and attribute data of the multi-value image data, and An image processing circuit that corrects a contour portion and performs a smoothing process, wherein the pixel of the contour portion of the processed image data is based on image data of a target pixel of the multi-valued image data and attribute data indicating an attribute of the image data Control means for controlling whether or not correction is performed, and contour correction means for correcting the contour of the processed image data based on the control of the control means , wherein the attribute data is the multi-value includes data indicating the size of the object that contains the image data of the target pixel of the image data, the control means, the line correction of the pixel of the contour portion of the processed image data in consideration of the size of the object And controlling whether. Here, when the attribute data indicates that the target pixel of the multi-valued image data is included in a thin or small object, the control unit avoids the correction of the contour portion by the contour portion correcting unit.

The image processing method of the present invention inputs multi-valued image data , processed image data obtained by performing pseudo halftone processing on the multi-valued image data, and attribute data of the multi-valued image data. An image processing method for performing a smoothing process by correcting a contour portion, wherein the pixel of the contour portion of the processed image data is based on image data of a target pixel of the multi-valued image data and attribute data indicating an attribute of the image data. and a control step of controlling whether or not to perform the correction, based on the control in the control step, and a contour correction step for correcting the contour of the processing image data, said attribute data, the multi includes data indicating the size of the object that contains the image data of the target pixel value image data, wherein in the control step, the correction of the pixel of the contour portion of the processed image data in consideration of the size of the object And controlling whether to perform. Here, when the attribute data indicates that the target pixel of the multi-valued image data is included in a thin or small object, correction of the contour portion is avoided.

The image processing program of the present invention inputs multi-valued image data , processed image data obtained by performing pseudo halftone processing on the multi-valued image data, and attribute data of the multi-valued image data. An image processing program for correcting an outline and executing image processing including smoothing processing , wherein the processed image is based on image data of a target pixel of the multivalued image data and attribute data indicating an attribute of the image data A control module that controls whether or not to correct pixels in the contour portion of the data; and a contour portion correction module that corrects the contour portion of the processed image data based on the control of the control module; data includes data indicating the size of the object that contains the image data of the target pixel of the multivalued image data, in the control module, of the object So that in consideration of the size controlling whether or not to correct the pixel of the contour portion of the processed image data, it causes the computer to execute. Here, when the attribute data indicates that the target pixel of the multi-valued image data is included in a thin or small object, the control module avoids correction of the contour portion by the contour portion correction module.

The storage medium of the present invention inputs multi-value image data, processed image data obtained by performing pseudo halftone processing on the multi-value image data, and attribute data of the multi-value image data, and the contour of the processed image data part a computer-readable storage medium storing an image processing program for performing image processing including the correction to smooth the, the image processing program, image data and the image of the target pixel of the multivalued image data A control module that controls whether or not to correct a pixel in the contour portion of the processed image data based on attribute data indicating an attribute of the data; and a control module that controls whether or not the contour portion of the processed image data corresponds to the control module . and a contour portion correction module to correct, the attribute data, the size of the object that contains the image data of the target pixel of the multivalued image data Includes data indicating, in the control module, so that in consideration of the size of the object for controlling whether or not to correct the pixel of the contour portion of the processed image data is the image processing program for causing a computer to execute It is characterized by that. Here, when the attribute data indicates that the target pixel of the multi-valued image data is included in a thin or small object, the control module avoids correction of the contour portion by the contour portion correction module.

  According to the present invention, it is possible to improve not only jaggy that occurs depending on the resolution of the printer, but also jaggy that occurs due to pseudo halftone processing. Such jaggy due to pseudo-halftone processing occurs at a resolution much lower than the resolution of the printer, and thus was noticeable in halftone characters and lines, but this can be improved. At that time, conventionally, for example, in a small letter of 3 points or less, or in a thin line of 1 dot or 2 dots, for example, the lower case letters are crushed or a hump-like lump appears in the jaggy part of the oblique thin line. It was possible to improve it.

  Furthermore, when the present invention is used, it is possible to cope with a so-called vectorized image in which an image read by a scanner is converted from bitmap data to outline data.

  Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. Here, as a preferred embodiment, a multifunction apparatus with a scanner using an electrophotographic technique will be described, but the image data targeted by the present invention is an image signal representing vector information. An image signal representing vector information is an image signal read by a scanner, not to mention PDL (Page Description Language) data sent by something like a PC or primitive intermediate data generated by interpreting PDL. Also included is a vectorization of. These vector information are data for indicating various objects such as text and graphics, and are finally converted into bitmap data. In the following embodiments, a copying machine or a printer for an electrophotographic process is particularly targeted. However, the present invention can also be applied to devices using other processes such as an ink jet or a display.

<Configuration Example of Entire Copier of the Present Embodiment>
FIG. 2 is a schematic cross-sectional view showing the mechanical configuration of the multifunction machine used in the present embodiment.

  As shown in FIG. 2, the mechanical configuration includes a color scanner section A and a printer section B.

  In the color scanner unit A, the document feeder 201A feeds documents one by one from the last page onto the platen glass 202A. Then, after the original reading operation is finished, the original on the platen glass 202A is discharged. When the document is conveyed onto the platen glass 202A, the lamp 203A is turned on, and the scanner unit 204A on which the lamp 203A is mounted is moved to scan the document for exposure. Reflected light from the original by this scanning is guided to a CCD color image sensor (hereinafter simply referred to as “CCD”) 209A by mirrors 205A, 206A, 207A and a lens 208A. The reflected light incident on the CCD 209A is color-separated into three colors R, G, and B and read as a luminance signal for each color. Further, the luminance signal output from the CCD 209A is input to an image processing unit (304; see FIG. 3) as image data of a digital signal by A / D conversion, and shading correction, gradation correction, quantization (N-value conversion), After performing known image processing such as smoothing processing, it is transferred to the printer unit B (305).

  In the printer unit B, the laser driver 221B drives the laser light emitting unit 201B, and causes the laser light emitting unit 201B to emit laser light corresponding to the image data for each color output from the image processing unit 304. The laser beam is irradiated onto the photosensitive drum 202B, and a latent image corresponding to the laser beam is formed on the photosensitive drum 202B. Then, a toner as a developer is attached to the latent image portion of the photosensitive drum 202B by the developing unit 203B. In FIG. 2, only one developing unit is shown for simplification of illustration, but toner is prepared for each color of C, M, Y, and K, and four developing units are provided accordingly. Of course. Further, instead of the above configuration, four sets of photosensitive drums, developing devices, and the like may be provided for each color.

  The recording paper is fed from either the cassette 204B or the cassette 205B at a timing synchronized with the start of the laser beam irradiation described above, and conveyed to the transfer unit 206B. Thereby, the developer attached to the photosensitive drum 202B can be transferred to the recording paper. The recording sheet to which the developer has been transferred is conveyed to the fixing unit 207B, and the developer is fixed to the recording sheet by the heat and pressure of the fixing unit 207B. Then, the recording paper that has passed through the fixing unit 207B is discharged by the discharge roller 208B, and the sorter 220B stores the discharged recording paper in a predetermined bin and sorts the recording paper.

  The sorter 220B stores the recording paper in the uppermost bin when the sorting is not set. When double-sided recording is set, the recording paper is conveyed to the discharge roller 208B, and then the rotation direction of the discharge roller 208B is reversed and guided to the refeed conveyance path by the flapper 209B. When multiple recording is set, the recording paper is guided to the refeed conveyance path 210B by the flapper 209B so as not to be conveyed to the discharge roller 208B. The recording sheet guided to the refeed conveyance path is fed to the transfer unit 206B at the timing described above. As is well known, the latent image and development processing and fixing for each color are realized by repeating the latent image formation and the like four times using the recording paper transport mechanism described above.

  Reference numeral 314 denotes a network cable, which is a system generally called Ethernet (registered trademark). This enables information exchange and data transfer between connected units by a protocol such as TCP / IP using a physical cable such as 10BaseT or 10Base5. Of course, it is not limited to wired using a network cable, and it goes without saying that a similar environment can be constructed even if wireless is used. Through such a network cable, intermediate data generated based on PDL data such as PDL data and display list, or an image bitmap signal can be received from a PC and output by the printer described above. ing. The object of the present embodiment is to apply the processing of the present invention to this PDL signal and intermediate data.

<Configuration Example of Control Unit of Multifunction Device of This Embodiment>
Next, a configuration example of the electrical control unit of the copying machine described with reference to FIG. 2 will be described with reference to the block diagram of FIG.

  The image reading unit 309 includes a lens 301, a CCD sensor 302, an analog signal processing unit 303, and the like. A document image 300 formed on the CCD sensor 302 via the lens 301 is converted into an analog electric signal by the CCD sensor 302. Is done. The converted image information is input to the analog signal processing unit 303 and subjected to analog / digital conversion (A / D conversion) after sample & hold, dark level correction, and the like.

  The digital signal thus converted is converted into a shading correction unit 1601, a color correction processing unit 1603, a filter processing unit 1604, a γ correction unit 1602, and a video count processing unit 1606 in the image processing unit 304 whose internal configuration is shown in FIG. The image forming processing unit 401, the smoothing processing unit 1605, and the like are processed, and then output to the printer 305. Among these processes, the configurations of the shading correction unit 1601, the color correction processing unit 1603, the filter processing unit 1604, and the γ correction unit 1602 and the contents executed by these processing units are directly related to the essence of the present invention. Therefore, the explanation is omitted.

  Also, PDL data transmitted from the host computer or the like through the network cable 314 in FIG. 1 is received by a network signal receiving unit 315 as an interface provided in the printer. The network signal receiving unit 315 includes a rasterizing unit (not shown) that interprets the received PDL data and generates bitmap data in units of pixels indicating an image.

  The PDL data holds data indicating the attribute of each object such as text, graphic, image, and the like. The rasterizing unit uses this attribute data to generate image area signals atr for each pixel along with the generation of image data. The image area signal atr will be described later in detail.

  Then, the image data generated by the rasterizing unit is input to the image processing unit 304 as in the case of the data input from the image reading unit 309, and is input to the filter processing unit 1604 as indicated by the arrow. Image processing is executed. The image area signal is input to the smoothing processing unit 1605. In the case of color image data, density data for each color of CMYK is generated, and subsequent processing is executed for each color data.

  Note that the rasterizing unit may be provided outside the network signal receiving unit 315.

  In the image formation processing unit 401, processing called normal screen processing or dither processing is performed. Since these processes are not directly related to the essence of the present invention, a detailed description thereof will be omitted. In this embodiment, an 8-bit image signal for each color input to the image formation processing unit 401 is converted into a 4-bit image signal and output to the smoothing processing unit 1605 as InDataS.

  On the other hand, the video count processing unit 1606 performs processing for measuring toner consumption. This is for calculating the toner consumption from the signal value output to the printer. Thus, the user is notified of the remaining amount of toner via the operation unit 313. The details of the processing are well known and will not be described.

  The signal from the network signal receiving unit 315 is connected behind the color correction processing unit 1603 because it is assumed that the signal received via the network is CMYK density data. is there. If the received signal is an RGB luminance signal, it goes without saying that the signal is connected in front of the color correction processing unit 1603 (not shown). In addition, although the signal received via the network is accurately transmitted through the CPU circuit unit 310, it is shown here as being directly connected to the image processing unit 304 as shown in FIG. .

  Returning to the description of FIG. 1, the printer 305 includes an exposure control unit (not shown) made of a laser or the like, an image forming unit (not shown), a transfer paper conveyance control unit (not shown), and the like. The input image signal is recorded on the transfer paper. The CPU circuit unit 310 includes a CPU 306, a ROM 307, a RAM 308, and the like, and comprehensively controls the image reading unit 309, the image processing unit 304, the printer unit 305, the operation unit 313, and the sequence of the apparatus. The operation unit 313 is provided with a RAM 311 and a ROM 312 in advance, and can display characters on a UI (user interface), store and display information set by the user. ing. Information set by the operation unit 313 by the user is sent to the image reading unit 309, the image processing unit 304, the printer 305, and the like via the CPU circuit unit 310.

  Among the configurations described above, characteristic components of the present embodiment are included in the image processing unit 304. Hereinafter, the smoothing processing unit 1605 in the image processing unit 304 will be described in detail.

  The following constituent elements are assumed to be realized by software, and are represented by programs created in C language, but these may have equivalent functions constructed by hardware or firmware. That is, even if each component or some components are configured using dedicated hardware such as ASIC, the same effect as that obtained by software can be obtained.

<Example of configuration of smoothing process of this embodiment>
FIG. 4 shows a configuration example of the smoothing process 1605 of this embodiment.

  Although only one color processing is shown in FIG. 4, data for four colors is input to the smoothing processing unit 1605 as shown in FIG. That is, FIG. 4 is configured to process CMYK colors independently. Since these processes are basically the same regardless of the color, in the present embodiment, only one of them is shown for the purpose of simplifying the description. Then, each block is demonstrated in order.

  First, 8-bit image data ImageData (InData ′) and an 8-bit image area signal atr are input to the entire smoothing processing unit 1605. As shown in FIG. 3, this image data has been subjected to processing by the γ correction unit 1602 and the like. The image area signal is a bit value generated by the rasterizing unit to represent the type of image (character, lower case, line, thin line, image, graphic, etc.). The image area signal atr is not limited to 8 bits. This is associated with each pixel of the image data ImageData.

  Hereinafter, processing executed by the smoothing processing unit 1605 will be described in order. The following description is performed by causing the CPU 306 to execute the C language program 501. Of course, it may be executed by hardware. In the drawings showing the target pixel and the reference pixel in the following drawings, the pixel surrounded by the thick frame is the target pixel, the pixel surrounded by the middle thick frame is the reference pixel in each processing, and the thin frame pixel is not referenced. Indicates a pixel. Such a reference pixel region is an example thereof, and the present embodiment is not limited to this.

(1. Bit conversion unit 402)
The bit conversion unit 402 performs a process of converting (so-called quantization) 8-bit image data, ImageData (InData ′), into 3-bit image data. Details of this processing are shown in FIG. 5 as an example of the C language program 501.

  In FIG. 5, “InData_K [yy] [xx]” 502 indicates 8-bit data (0 to 11111111 = 255) input as InData ′, which is indicated by “InData_K [yy] [xx]” 503. Is the 3-bit data (0 to 111 = 7) to be output. In FIG. 4, 3-bit data output from the bit converter 402 is described as InData.

  Also, what is written in “params->” of the C language program 501 represents a parameter. In this embodiment, seven types of parameters from “params → SevenConversionK7 to K1” are set. Specifically, 8-bit data is set for each parameter. For example, the values are “224, 192, 160, 128, 96, 64, 32”, respectively. With this configuration, 8-bit input data is converted into 3 bits at 32 equal intervals. For example, if InData ′ ≧ 224, 3 bit data = 7 is output, and if InData ′ <32, 3 bit data = 0 is output. The parameters are not limited to regular intervals as in the above example, but can be arbitrarily changed depending on which density level is controlled in detail.

  The bit conversion unit 402 is configured to compare such a parameter value with the size of each if statement and output 3 bit image data (InData). The image data converted into 3 bits by the processing described above is output from the bit conversion unit 402 and input to the control signal generation unit 403.

(2. Control signal generator 403)
The control signal generation unit 403 generates an identification signal for identifying an image on which smoothing processing is performed and image data for generating an edge signal. The identification signal OutDataZ (= out) is 1 bit, and details are as shown in the C language program 601 of FIG.

  More specifically, by executing the if statement 602 in FIG. 6, the signal is generated as an internal signal in accordance with the image area signal atr. The internal signal is composed of four elements (4 bits): an element “thin” that represents a small letter and a thin line, an element “graphic” that represents a graphic, an element “line” that represents a line, and an element “font” that represents a font. Signal. These signals are “1” when each pixel constituting the image data corresponds to any one of the above elements, and “0” when there is no pixel. That is, in the case of the pixels constituting the line, the bit representing the line is 1.

  Further, regarding the identification signal “thin” of the small letter / thin line, the thin is “0” in the case of the fine line or the small letter, and “1” is otherwise. Therefore, "graphic", "line", and "font" are exclusively 1, but "thin" is "graphic", "line", " It may be duplicated with “font”. These internal signals are all generated according to image area signals such as 0x02 and 0x04 sent from the rasterizing unit (not shown).

Specifically, in this embodiment,
atr = 0x02 (00000010): "image (bitmap)"
atr = 0x04 (00000100): "graphic"
atr = 0x08 (00001000): "line"
atr = 0x10 (00010000): "font (character)"
atr = 0x20 (00100000): "thin-graphic"
atr = 0x40 (01000000): "thin-line"
atr = 0x80 (10000000): "thin-font (lowercase)"
A thin graphic with atr = 0x20 assumes a case in which a figure enclosed by a rectangle is elongated. These atr signals are image area signals transmitted by the PDL, and are configured to identify these attributes on the PDL side.

By the way, here is a combination of attribute signals that distinguish thin lines and lowercase letters.
0x40 (01000000)
0x80 (10000000)
However, it is needless to say that this can be realized by defining a flag having a meaning such as “thin ~” or “small ~” in an arbitrary bit instead of such a combination.

For example, when the flag is defined in LSB, it is as follows.
atr = 0x02 (00000010): "image (bitmap)"
atr = 0x04 (00000100): "graphic"
atr = 0x08 (00001000): "line"
atr = 0x10 (00010000): "font (character)"
atr = 0x84 (10000100): "thin-graphic (thin graphic)"
atr = 0x88 (10001000): "thin-line"
atr = 0x90 (10010000): "thin-font (lowercase)"
Thus, the image area signal shown in FIG. 6 is only an example for explaining the present embodiment, and it goes without saying that the image area signal is not limited to this image area signal value.

  Next, the if statement 603 is also a characteristic part of the present embodiment. This is based on an input image signal (InData: 3 bit) value output from the bit conversion unit 402 and an object signal that is an internal signal. This is where (OutDataZ = out) is generated. Here, "graphic (graphic)", "line (line)", "font (character)" is a condition, and whether or not it is "thin" is irrelevant. Reg_Zcheck3 [0] to reg_Zcheck3 [2], which are compared with the input image signal (InData: 3bit) value, are register values, and the initial density of the control signal (OutDataZ = out) can be set for each object. ing. By setting these register values, it is possible to control whether the contour correction processing is applied only to lines having a predetermined density or higher, or the contour correction processing is applied only to characters having a predetermined density or higher. For example, when the object signal indicates “font”, the input image signal (InData: 3 bit) value ≧ reg_Zcheck3 [0] is determined, and when YES, 1 is output to the control signal (OutDataZ = out). Then, the image signal generation unit 404 is used to determine whether or not to apply contour correction processing. Incidentally, since the input image signal (InData) is 3 bits, these registers are also 3 bits.

  Finally, the if statement 604 is a switching unit that prevents the outline correction processing from being applied to the thin line / lower case. This is also a characteristic part of this embodiment, and it is possible to specify in detail which object is controlled by the register ThinJudge.

  For example, when the register ThinJudg = 1, the control is “graphic”. In the case of the register ThinJudg = 1, if “graphic” = 1 and “thin” = 1, 1 is output to the control signal (OutDataZ = out), and the input data (InData of the portion to be subjected to contour correction processing) ) Is changed to the value of the register reg_Zcheck.

  If the processing of the if statement 604 is expressed in relation to the if statement 603, "thin" = 1 (thin / small) is set if specified by the register ThinJudg even if each object does not exceed the predetermined density. After determining, 1 is output to the control signal (OutDataZ = out), and InData is changed to the value of the register reg_Zcheck. The value of reg_Zcheck is counted by a predetermined value pixel count 1003 in FIG. 11 described later, and is used to reset the “edge” signal.

  This is to prevent the adverse effect caused by the contour correction processing on an object whose gradation changes gently, such as gradation, when an arbitrary density is specified by the above-described if statement 603. Defect avoidance processing is shown in 1003, 1004, 1403, 1404 and the like below. Although details of these processes will be described later, an outline of the relationship with the control signal generation unit 403 is shown below.

  In the C language program shown in FIG. 6, first, an object such as a character or graphic is determined using an if statement 602. Next, in the if statement 603, a signal (out) for performing the smoothing process is generated only for an object having an arbitrary density or higher. However, the problem (disadvantage) here is a thin line with a width of 1 pixel or a small letter of about 1 to 2 points. When this smoothing process is applied to such an object, the jaggy part of the thin line (rattle) There is a case where the part is rattling like a bump with a delicate density balance related to the characteristics of the electrophotographic printer. In addition, characters are crushed even if they are not rattled.

  Therefore, in order to solve these problems, a thin line (lower case) flag is obtained as an image area signal from PDL (PC at the end of the network), and this is “thin” of if statement 604. An object having this flag (thin) transmits the information to subsequent processing by rewriting inData (input image signal) with an arbitrary register (reg_Zcheck). The subsequent processing includes 1003 in FIG. 11 and 1403 in FIG. At this point, the register (reg_Zcheck) rewritten earlier is counted, and when this count value exceeds an arbitrary threshold (params-> thre_B), a flag (edge = 0) for not performing this smoothing process is generated. To do.

  As described above, in the control signal generation unit 403, 3 bits of image data converted from 8 bits of image data not subjected to pseudo halftone processing such as screen processing in the image formation processing unit 401, and 1 bit corresponding to the object The control signal (OutDataZ = out) is generated and a smoothing process in the next-stage image signal generation unit 404 is realized based on the data.

(3. Image signal generator 404)
Next, the image signal generation unit 404 will be described with reference to FIG. 7, but before the detailed processing is described, the outline will be described first.

  A feature of the image signal generation unit is that a non-smoothing processing unit is detected from the OutDataZ signal, and a signal obtained by performing smoothing processing on all InData signals and an unsmoothed processing signal (InDataS) are switched and output.

  That is, instead of detecting a smoothing processing unit as in normal smoothing processing, a problem that there is a pattern that does not require smoothing processing is improved by detecting a non-smoothing processing unit. In short, since the basic configuration is such that smoothing processing is performed on all pixels, the conventional problems can be improved.

  Furthermore, instead of pattern matching processing, pixels near the target pixel are divided into regions, and the non-smoothing processing unit is detected according to the pixel count value for each region, thereby simplifying and increasing the accuracy of the processing. .

  By the way, an image area signal (OutDataZ) is used as a signal for detecting the non-smoothing processing unit. This makes it possible to switch processing for each object (character, graphic, photograph, etc.).

  Hereinafter, details of this processing will be described for each block.

  The input signals are a 1-bit control signal “OutDataZ” and a 3-bit image signal “InData” output from the control signal generation unit 403, and a 4-bit signal “InDataS after image formation processing output from the image formation processing unit 401”. "It is. Based on the input signal, the image signal generation unit 404 selects the output of the first image signal correction unit 705 when the control signal is 1 when the selector 707 is selected by the control signal (DataZ = OutDataZ) of the target pixel. When the value is 0, the output of the second image signal correction unit 706 is selected, and 4-bit image data OutputData that is preferably smoothed or avoids the smoothing process is output.

  Here, the first image signal correction unit 705 pays attention to the arrangement of 0 control signals (DataZ = OutDataZ), and the second image signal correction unit 706 pays attention to the arrangement of 1 control signals (DataZ = OutDataZ). Perform correction or harm avoidance processing.

  Hereinafter, details of each process will be described in order.

(3-1. FiFo memories 701 to 703)
Since these signals are subjected to area processing (for example, simultaneous reference processing of “OutDataZ” and “InData” in areas of 7 × 7 and 15 × 7 in FIGS. 11 and 15) in the later-described processing, the number of FiFo memories is small. Lines are prepared. The details of the number of lines are 6 lines of the FiFo memory 701, 6 lines of the FiFo memory 702, and 3 lines of the FiFo memory 703. The 1-bit control signal "OutDataZ" is an area of 7 lines at a time, and the 3bit image signal "InData “The area of 7 lines at a time and the 4-bit signal“ InDataS ”after image formation processing can refer to the area of 4 lines at a time in the first and second image signal correction units thereafter. These signals are used to perform a process to be described later, and then a 4-bit signal “OutputData” is output.

(3-2. Random number generator 704)
First, the details of the random number generation unit 704 in FIG. 7 are shown as a C language program 801 in FIG.

  In FIG. 8, there are two functions, a function 802 and a function 803, but the function 802 is for initialization and is executed only once. On the other hand, the function 803 is repeatedly processed for each pixel. Specifically, as initialization, first, 0 is set in 26 1-bit registers “p [ii] (ii = 0 to 25)” of 0 to 25 in the function 802, and then “p [2], Only in the locations of p [4], p [8], p [16] ", 1-bit parameter values" params-> rd1, rd2, rd3, rd4 "are set. The process of generating the random number rd (out) is performed by repeating the calculation of the function 803 for each pixel.

  The operation of the function 803 is “p [0] = ((p [25] ^ p [24] ^ p [23] ^ p [22]) & 1)” and p [25] to p [22] Performs an exclusive OR (XOR) operation and assigns the result to p [0]. Then, each data is shifted by a for statement, and a 1-bit signal of p [17] is output as a random value rd (out). The 1-bit random value rd (out) obtained in this way is output to the first image signal correction unit 705 and the first image signal correction unit 706 shown in FIG.

(3-3. First Image Signal Correction Unit 705)
Hereinafter, the first image signal correction unit 705 will be described with reference to FIG.

  Here, as shown in FIG. 9, a 1-bit control signal “OutDataZ” used for determining whether or not to perform the contour correction processing described above, a change to the value of the register reg_Zcheck by the control signal generation unit 403, etc. 3 bits "InData" including the above processing, "InDataS" screen-processed by the image forming processing unit 410, and the random number "rd" from the random number generation unit 704 are input, and 4 bits "OUTData_0" are output as a correction signal. It is the composition which becomes.

  The internal processing is roughly divided into three. The first correction unit second edge detection unit 101, the first correction unit first edge detection unit 102, and the first correction unit image output switching unit 103. is there.

(3-3-1. Second edge detection means 101 for the first correction unit)
The details of the second edge detecting means 101 for the first correction unit are as shown in the C language program 901 of FIG.

  As shown in FIG. 10, the processing of the second edge detection means 101 for the first correction unit is roughly divided into a horizontal count process 902 and a vertical count process for counting the number of pixels in which the 1-bit control signal “OutDataZ” is 0. It is divided into two, 904. The horizontal counting process 902 is a process of counting 0 out of 7 pixels including 3 pixels on the left and right of the target pixel in the horizontal direction when the upper or lower pixel of the target pixel is 0. This is shown in 903. On the other hand, the vertical count process 904 is a process of counting 0 out of 7 pixels including 3 pixels above and below the target pixel in the vertical direction when the left or right pixel of the target pixel is 0. The situation is shown at 905.

  Both of the above-mentioned processes try to detect the edge from the count of the number of pixels where the 1-bit control signal is 0. In both cases, the horizontal direction and the vertical direction are counted by counting the number of pixels instead of the filter processing like Laplacian. It is characterized in that the edge is detected. Specific processing is as shown in the horizontal count processing 902 and the vertical count processing 904 described above. The count result obtained by such processing is output as 3-bit fg_x and fg_y in the pixel of interest.

  That is, the output 3-bit fg_x and fg_y are set so that the 1-bit control signal “OutDataZ” of 7 pixels in the horizontal and vertical directions including the target pixel is 0 (according to the control signal generation unit 403 in FIG. The number of pixels is less than a predetermined density and there is no avoidance process when “thin = 1”.

(3-3-2. First edge detecting unit 102 for the first correcting unit)
Next, the first edge detection unit 102 for the first correction unit, which is another edge detection unit, will be described. Details of the processing are shown in FIG. This process is roughly divided into three stages. In the first 0 control signal detection 1002, if all 1-bit control signals “OutDataZ” are not 1 in the 7 × 7 area including the target pixel, “edge” is set to 1, but in the second and third stages, In the 15 × 7 area, “edge” is changed to 0 based on the number of pixels of “reg_Zchech” replaced by the “thin” determination in the if statement 604 of FIG.

  First, the 0 control signal detection 1002 detects whether or not there is a 0 control signal in the area of the parameter “EdgeSizeB” as indicated by 1005. The result is an edge signal. If there is even one control signal of 0, “edge” is set to 1.

  Next, in a predetermined value pixel count 1003, as indicated by 1006, the number of pixels having the same value as the parameter “reg_Zcheck” in the 15 × 7 area is counted. The count result is the fg signal.

  Finally, in the edge signal reset 1004, when the above-described fg count value is greater than or equal to the threshold parameter “thre_B”, the above-described edge signal is set to 0, and otherwise, the edge signal is output as it is. .

  The feature here is that edge processing is performed without using a filter like Laplacian as described above, and whether the same value as the parameter "reg_Zcheck" exists in the area is checked. Only when there is a predetermined number, the edge information is cleared.

  The processing for clearing the edge information is for avoiding the adverse effect of performing the contour correction processing from the predetermined density described in the if statements 603 and 604 in FIG. As described above, the adverse effect is to prevent the contour portion correction process from being applied to the object at the halfway density of the gradation portion. That is, this processing is usually intended to be performed only on the outline of the object, and processing is not performed on other portions.

  Through the processing described above, a 1-bit edge signal is generated and "EdgeC" is output.

(3-3-3. First Correction Unit Image Output Switching Processing Unit 103)
Next, the first correction unit image output switching means 103 will be described. Details of the processing are shown in FIG.

  In this processing, as shown in FIG. 12, “fg_x”, “fg_y” output from the first edge detecting unit 101 for the first correcting unit, and the first edge detecting unit 102 for the first correcting unit are used. The output “EdgeC”, “InData” from the control signal generation unit 403, screen data “InDataS” from the image formation processing unit 401, random number “rd” from the random number generation unit 704, and the like are input. After application, 4bit "OUTDATA_0" is output. The details of the process are roughly divided into an output control process 1102, an output control process 1103, and an output control process 1104. Hereinafter, it will be described in order.

First, in output control processing 1102,
((fg_x> = (params−> seriateBKx)) || (fg_y <= (params−> seriateBKy))) && edge! = 0 ... (1)
Check for. params-> seriateBKx and params-> seriateBKy are 3-bit parameters.

  Specifically, it is checked whether fg_x or fg_y obtained for the target pixel by the second edge detecting unit 101 for the first correction unit is greater than or equal to the above parameter. It is checked whether or not the edge signal obtained for the target pixel by the first correction unit first edge detecting means 102 is other than zero. This edge signal is equivalent to EdgeC described above. Here, when the edge signal is other than 0, there are some 0 data in a predetermined 7 × 7 area as described in FIG. 11, and the same value as “reg_Zcheck” in the 15 × 7 area. Is less than a predetermined number.

  In short, when the edge signal of the pixel of interest is other than 0, the fact that the comparison sentence of (1) is satisfied is that the pixel of interest is in an edge portion where a predetermined number or more of edge signals 0 continue in the horizontal and vertical directions. It is shown that. In other words, it indicates that the edge portion including the target pixel is an edge portion other than horizontal and vertical.

  For such an edge, a calculation within the range indicated by 1105 is performed. This calculation is a product-sum operation (Sum + =) of the parameter “params−> mask2” and 7-bit input data “InData (Data)” of 7 pixels in the horizontal and vertical directions including the target pixel. This product-sum operation is not limited to that shown in FIG. 12, but is basically a digital filter process such as smoothing, and is configured to generate data for outputting halftone data to the edge portion where jaggy occurs. ing.

  The calculation result data created here is converted into 4 bits by a look-up table (memory) as indicated by LUTI so as to be finally 4 bits, and then output.

  Next, the output control processing 1103 does not apply to the conditional statement (1), but the processing when the edge! = 0 --- (2) is satisfied (the edge signal corresponding to the target pixel is other than 0). I'm doing it. The condition (2) basically means that the edges are in the horizontal and vertical directions. The processing shown in the output control processing 1103 is performed on such an edge.

  Specifically, when the edge signal of the pixel of interest is other than 0 and the 3-bit InData (Data [yy] [xx]) of the pixel of interest is other than 0, {temp = (Data [yy] [xx]) + rd} is a process of adding a 1-bit random number generated by the random number generation unit 704 to 3-bit InData, and outputting 0 (temp = 0) in cases other than the above conditions. Note that temp is 7 at maximum.

  Since Data (InData) has been converted into 3 bits by 402 of the bit conversion unit 1, it is necessary to convert it into 4 bits using a table such as LUTE and output it.

  Needless to say, the addition of the random number rd described above is not essential and may not be added (when 0 is added). However, adding this random number has the effect of improving the gradation of the edge portion.

  Finally, the output control processing 1104 performs processing when the conditions (1) and (2) described above are not satisfied (that is, edge = 0). That is, it is a place other than the edge. For such a location, the input InDataS value is output as it is. In other words, data subjected to image formation processing such as pseudo intermediate processing by the image formation processing unit 401 is output as it is.

  As described above, in the contour correction processing described above, the processing data (InData, DataZ, reg_Zcheck, etc.) for detecting the edge portion is different from the output data of the image forming processing 401, that is, pseudo halftone processing data. This is different from smoothing. As a result, even for images that have undergone image formation processing such as a screen, smoothing processing is applied to the edge portion without any problem, and even for images that have image degradation such as JPEG, By creating 3bit data and creating 1bit signal, smoothing can be applied without any problem. Furthermore, according to the present embodiment, the contour correction process can be freely controlled for each object.

(3-4. Second Image Signal Correction Unit 706)
Next, the second image signal correction unit 706 shown in FIG. 7 will be described with reference to FIG.

  In the processing shown in FIG. 13, as in the case of the first image signal correction unit 705, the aforementioned “OutDataZ”, “InData”, “InDataS”, “rd” are input, and 4-bit “OUTData_1” is input as the correction signal. It is configured to output. The input signal is the same as that described in FIG.

  The internal processing is also divided into three as in FIG. 9 described above. The second correction unit second edge detection unit 1201, the second correction unit first edge detection unit 1202, and the second correction unit use This is image output switching means 1203.

(3-4-1. Second Edge Detection Unit 1201 for Second Correction Unit)
The details of the second edge detection unit 1201 for the second correction unit are as shown in the C language program 1301 of FIG.

  As shown in FIG. 14, the processing of the second edge detecting unit 1201 for the second correction unit is roughly divided into a horizontal count process 1302 for counting the number of pixels in which the 1-bit control signal “OutDataZ” is 1, and a vertical count. The process is divided into two processes 1304. The horizontal counting process 1302 is a process of counting non-zero in the horizontal direction among seven pixels including three pixels on the left and right of the target pixel in the horizontal direction when the upper or lower pixel of the target pixel is other than zero. Yes. The situation is shown at 1303. On the other hand, the vertical counting process 1304 is a process of counting non-zero in the vertical direction among seven pixels including three pixels above and below the target pixel in the vertical direction when the left or right pixel of the target pixel is other than zero. It has become. The situation is shown in 1305.

  Both are processing for detecting an edge from a 1-bit control signal other than 0 as described above. However, as in the case of FIG. 9 described above, both are not filter processing such as Laplacian, but count the number of pixels other than 0. Edges in the horizontal and vertical directions are detected. By the way, it is divided into left and right like fg_x1 and fg_x2, or divided up and down like fg_y1 and fg_y2, and when there is a control signal other than 0 in both left and right and up and down, the count is 0. For example, if (fg_x1! = 0 && fg_x2! = 0) {fg_x = 0;}, which is different from the second edge detection means 101 for the first correction unit described above.

  As described above, the count result other than 0 obtained by the processes shown in the horizontal count process 1302 and the vertical count process 1304 is output as 3 bits of fg_x and fg_y corresponding to the target pixel.

(3-4-2. First Edge Detection Unit 1202 for Second Correction Unit)
Next, the second edge detecting unit first edge detecting unit 1202 which is another edge detecting unit will be described. Details of the processing are shown by a C language program 1401 in FIG. This process is roughly divided into three stages.

  First, as shown in 1405, it is detected whether there is one control signal in the area of the parameter “EdgeSizeW” as shown in 1405. The result is an edge signal.

  Next, in the portion indicated by the predetermined value pixel count 1403, as shown by 1406, the number of pixels having the same value as the parameter “Zcheck” in the 15 × 7 region is counted. The result is the fg signal.

  Finally, the edge signal reset 1404 is configured to output the edge signal as it is when the count value of fg described above is equal to or greater than the parameter “thre_W”, otherwise the edge signal is set to 0. .

  The major difference from conventional smoothing is that edge processing is performed without using a filter like Laplacian as described above, and whether the same value as the parameter "Zcheck" exists in the area, Only when there are an arbitrary number of the same values, the above-described edge information is cleared.

  Thus, the obtained effect is equivalent to that obtained in the description of FIG. Since the contents of the effect are repeated, the explanation is omitted. By such processing, a 1-bit edge signal is generated and “EdgeC” is output.

(3-4-3. Second Correction Unit Image Output Switching Unit 1203)
Next, the second correction unit image output switching means 1203 will be described. Details of the processing are shown by a C language program 1501 in FIG.

  Since the basic processing is equivalent to the first correction unit image output switching means 103 described above, detailed description thereof is omitted. However, the meanings of the signals fg_x, fg_y, and EdgeC (edge) are different. Although these meanings are as described above, fg_x, fg_y, and EdgeC input to the first correction unit image output switching unit 103 count the number of pixels with the control signal (DataZ) of 0. It was a result. On the other hand, fg_x, fg_y, and EdgeC shown in FIG. 16 count the number of pixels whose control signal (DataZ) is 1. The point is very different. Others are basically equivalent.

(3-5. Selector 707)
The output “OUTData_1” of the first image signal correction unit 705 and the output “OUTData_2” of the second image signal correction unit 706 described above are input to the selector 707 shown in FIG. OutputData "is output.

  The selector 707 performs a process of switching the output according to the data of the target pixel position. The pixel of interest data is the control signal (DataZ = OutDataZ) described above. When this signal is 1, the output of the first image signal correction unit 705 is selected, and when it is 0, the second image signal correction is performed. The output of the unit 706 is selected.

<Operational effects of this embodiment>
The result of performing the processing described above is output to the printer 305 as the smoothing processing result.

  The output image is shown in FIG. The point of interest is an edge portion. As shown in FIG. 17, data is output lightly so as to fill in between the screen patterns.

  Although not shown, as described above, the edge portion can be improved without problems even for an image subjected to irreversible compression processing such as JPEG. The reason is that, when creating an image for edge detection, bit conversion is performed to 3 bits, and furthermore, since a 1-bit control signal is created from the image, it is possible to remove subtle deterioration information due to compression. It is.

  Similarly, although not shown in the figure, it is possible to perform control without applying the above-described processing only to a small line that is a feature of the present invention and has a line width of 1-2 pixels (arbitrary).

<Other embodiment examples>
In the present invention, a storage medium recording software program codes for realizing the functions of the above-described embodiments is supplied to a system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the storage medium in the storage medium. Needless to say, this can also be achieved by reading and executing the programmed program code.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention. As a storage medium for supplying the program code, for example, a floppy disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) operating on the computer based on the instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included.

  Further, after the program code read from the storage medium is written to a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the card or the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

  For example, it goes without saying that this processing is performed by a driver on a PC.

It is a figure which shows the outline of a block configuration of the control system of this embodiment. 1 is a diagram illustrating an outline of a mechanical configuration of a copier that constitutes a system of an embodiment. It is a block diagram which shows the outline of the flow of the image processing signal of this embodiment. It is a block diagram which shows the outline | summary of the smoothing process of this embodiment. FIG. 5 is a block diagram showing a bit conversion unit in FIG. 4 and an example of a C language program. FIG. 5 is a block diagram illustrating a control signal generation unit in FIG. 4 and an example of a C language program. It is a block diagram which shows the image signal generation part of FIG. FIG. 8 is a block diagram illustrating a random number generation unit in FIG. 7 and a diagram illustrating an example of a C language program. It is a block diagram which shows the 1st image signal correction | amendment part of FIG. FIG. 10 is a block diagram illustrating a second edge detecting unit for the first correction unit in FIG. 9 and a diagram illustrating an example of a C language program. FIG. 10 is a block diagram illustrating a first edge detection unit for the first correction unit in FIG. 9 and a diagram illustrating an example of a C language program. FIG. 10 is a block diagram showing the first correction unit image output switching means of FIG. 9 and an example of a C language program. It is a block diagram which shows the 2nd image signal correction | amendment part of FIG. FIG. 14 is a block diagram illustrating a second edge detecting unit 2 for the second correcting unit in FIG. 13 and an example of a C language program. FIG. 14 is a block diagram illustrating a first edge detecting unit for the second correction unit in FIG. 13 and a diagram illustrating an example of a C language program. FIG. 14 is a block diagram illustrating a second correction unit image output switching unit in FIG. 13 and a diagram illustrating an example of a C language program. It is an image figure which improved the jaggy of the screen processing by this embodiment. It is an image figure which shows jaggy. It is an image figure which shows the state which improved jaggy by the conventional smoothing. It is the image figure which applied the screen process to the halftone character. It is an image figure which shows the jaggy generated by a screen process.

Claims (15)

And the multi-level image data, and processing the image data of the multivalued image data processed halftone, the type and attribute data of the multivalued image data, image processing for output by correcting the contours of the processed image data An image processing apparatus having a circuit ,
The image processing circuit is
Control means for said based on the multivalued image attribute data indicating the attribute of the image data and the image data of the target pixel data, to control whether or not to correct the pixel of the contour portion of the processed image data,
Contour correction means for correcting the contour of the processed image data based on the control of the control means ;
The attribute data includes data indicating a size of an object including image data of a target pixel of the multi-value image data ,
The image processing apparatus according to claim 1, wherein the control means controls whether or not to correct a pixel in a contour portion of the processed image data in consideration of the size of the object. The image processing apparatus according to claim 1, wherein the attribute data includes data indicating that a target pixel of the multi-value image data is included in a thin or small object. The image processing apparatus according to claim 1, wherein the attribute data includes data indicating that a target pixel of the multi-valued image data is included in a line, graphic, or character object. The control unit corresponds to contour detection data generated based on the image data of the target pixel of the multi-valued image data and the attribute data indicating the attribute of the image data. The image processing apparatus according to claim 1, wherein whether or not correction is performed is controlled. The contour correction means detects a contour portion based on a pixel arrangement of the contour detection data in a first state and corrects the contour portion in a second state different from the first state. Second contour correction means for detecting and correcting the contour based on the pixel arrangement of the contour detection data,
The control means selects the first contour correction means when the contour detection data is in the first state, and selects the second contour correction means when the contour detection data is in the second state. The image processing apparatus according to claim 4. When the attribute data indicates that the target pixel of the multi-value image data is included in a thin or small object, the control unit avoids the correction of the contour portion by the contour portion correction unit. The image processing apparatus according to claim 2.   The image processing apparatus according to claim 6, wherein the control unit avoids detection of a contour portion by the contour portion correcting unit. Multi-valued image data, processed image data obtained by performing pseudo halftone processing on the multi-valued image data, and attribute data of the multi-valued image data are input, and an image that is subjected to smoothing processing by correcting the contour of the processed image data A processing circuit,
Control means for said based on the multivalued image attribute data indicating the attribute of the image data and the image data of the target pixel data, to control whether or not to correct the pixel of the contour portion of the processed image data,
Contour correction means for correcting the contour of the processed image data based on the control of the control means ;
The attribute data includes data indicating a size of an object including image data of a target pixel of the multi-value image data ,
The image processing circuit, wherein the control means controls whether or not to correct a pixel in a contour portion of the processed image data in consideration of the size of the object. When the attribute data indicates that the target pixel of the multi-value image data is included in a thin or small object, the control unit avoids correction of a contour portion by the contour portion correction unit. The image processing circuit according to claim 8. Multi-valued image data, processed image data obtained by performing pseudo halftone processing on the multi-valued image data, and attribute data of the multi-valued image data are input, and an image that is subjected to smoothing processing by correcting the contour of the processed image data A processing method,
And a control step of the based on the multivalued image attribute data indicating the attribute of the image data and the image data of the target pixel data, to control whether or not to correct the pixel of the contour portion of the processed image data,
A contour correction step for correcting the contour of the processed image data based on the control in the control step ;
The attribute data includes data indicating a size of an object including image data of a target pixel of the multi-value image data ,
In the control step, the image processing method is characterized by controlling whether or not to correct a pixel in a contour portion of the processed image data in consideration of the size of the object. The image processing method according to claim 10, wherein when the attribute data indicates that a target pixel of the multi-value image data is included in a thin or small object, correction of the contour portion is avoided. Including multivalued image data, processed image data obtained by performing pseudo halftone processing on the multivalued image data, and attribute data of the multivalued image data, and correcting a contour portion of the processed image data to include a smoothing process An image processing program for executing image processing,
A control module the based on the multivalued image attribute data indicating the attribute of the image data and the image data of the target pixel data, to control whether or not to correct the pixel of the contour portion of the processed image data,
A contour correction module that corrects the contour of the processed image data based on the control of the control module ;
The attribute data includes data indicating a size of an object including image data of a target pixel of the multi-value image data ,
An image processing program for causing the computer to execute, in the control module, controlling whether or not to correct a pixel in a contour portion of the processed image data in consideration of the size of the object. When the attribute data indicates that the target pixel of the multi-valued image data is thin or included in a small object, the control module avoids correction of a contour portion by the contour portion correction module. The image processing program according to claim 12. Including multivalued image data, processed image data obtained by performing pseudo halftone processing on the multivalued image data, and attribute data of the multivalued image data, and correcting a contour portion of the processed image data to include a smoothing process a computer-readable storage medium storing an image processing program for performing image processing,
The image processing program is
A control module the based on the multivalued image attribute data indicating the attribute of the image data and the image data of the target pixel data, to control whether or not to correct the pixel of the contour portion of the processed image data,
A contour correction module that corrects the contour of the processed image data based on the control of the control module ;
The attribute data includes data indicating a size of an object including image data of a target pixel of the multi-value image data ,
The control module is an image processing program for causing a computer to execute control to determine whether or not to correct a pixel in a contour portion of the processed image data in consideration of the size of the object. Storage medium. When the attribute data indicates that the target pixel of the multi-valued image data is thin or included in a small object, the control module avoids correction of a contour portion by the contour portion correction module. The storage medium according to claim 14.

Images