JPH0433074A - Graphic processor - Google Patents

Abstract

PURPOSE:To calculate an area ratio at high speed by deciding the ratio of an area to be painted-out in an edge part picture element based on input / output coordinates when a vector data crosses the edge part picture element, and setting a prescribed constant as the area ratio when an end point exists in the edge part picture element. CONSTITUTION:An anti-aliasing processing is executed to adjust an output from the edge part picture element of the vector data based on the ratio of the area to be painted-out, and to smoothly express unevenness in the edge part of an output picture. Then, it is decided whether the end point of the vector data exists in the edge part picture element or not, and when the end point does not exist in the edge part picture element, the ratio of the area to be painted-out in the edge part picture element is decided based on input / output coordinates (x1, y1) and (x2, y2) when the vector data crosses the edge part picture element. On the other hand, when the end point exists in the edge part picture element, the prescribed constant is set as the ratio of the area to be painted-out in the edge part picture element. Thus, without executing sub pixel division and counting the number of areas to be painted-out, the area ratio can be calculated at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a graphic processing device that performs anti-aliasing processing to remove jagged edges of an output image.
More specifically, the present invention relates to a graphic processing device that can perform 8 anti-aliasing processing at high speed.

[Prior Art] In the field of computer graphics, when displaying an image on a CRT, which is an output medium, a technique called anti-aliasing processing is used to make the displayed image more beautiful. This process applies brightness modulation to the jagged parts (called aliases) on the stairs as shown in Fig. 25+g(a), visually changing the display image to
)).

Conventional graphic processing equipment uses the uniform averaging method and the heavy weight method.
The average method, the convolution method, etc. are generally applied as anti-aliasing processing methods.

■The uniform averaging method calculates each pixel by N*M (N,
After decomposing the pixel into sub-pixels (M is a natural number) and performing rask calculation at high resolution, the brightness of each pixel is determined by taking the average of N*M sub-pixels. Figure 26(a)
, (b), anti-aliasing processing using the uniform averaging method will be specifically explained. If the edge of the image overlaps a certain pixel (here, it is assumed that the image is connected to the lower right of the diagonal line), and when anti-aliasing processing is not performed, as shown in Figure (a),
The brightness kfd of this pixel is assigned the highest brightness of the displayable gradations (for example, kid·255 for 256 gradations). When applying anti-aliasing processing to this pixel using the uniform averaging method with N=M=7, the pixel is decomposed into 7*7 sub-vixels and the number of sub-vixels covered by the image is calculated as shown in the same figure. Count. The count number (28) is divided by the total number of subpixels in one pixel (49 in this case) and normalized (averaged)
The brightness of that pixel is calculated by multiplying the brightness by the maximum brightness (255). In this way, in the uniform averaging method, the brightness of each pixel is determined by taking into consideration how the image is distorted in each pixel.

■Weighting is an averaging method The weighting and averaging method is a partial modification of the uniform averaging method. In contrast, the weighted averaging method assigns a weight to each sub-vixel, and the influence on the brightness kid of that sub-vixel differs depending on which sub-vixel the image falls on. That's what I do. Note that the weight at this time is given using a filter.

With reference to FIGS. 27(a) and (b>), FIG. 26(a)
), the same dividing method (N=M=7) and the weighting averaging method are shown.

FIG. 27(a) shows a filter (here, conef
i 1 ter ), and the corresponding sub-vixel is given the same weight as this characteristic. For example, the weight of the sub-vixel in the upper right corner is 2. When an image is applied to each sub-vixel, the weight value given by the filter characteristics becomes the count value of that sub-vixel. Figures 1 and 2) show different display patterns of images depending on the weights of sub-vixels. in this case,
Counting the weighted sub-vixels of the image results in 199. This value is divided by the sum of the filter values (336 in this case) corresponding to uniform averaging, averaged, and multiplied by the maximum brightness to calculate the brightness of this pixel. The filter shown in Fig. 28(a)
, (b), (C), and (d) are excellent.

■Convolution Integration Method The convolution integration method is a method that refers to the appearance of surrounding pixels when determining the brightness of one pixel. That is, around the l pixel whose brightness is to be determined, N
The "×N" pixel is considered to correspond to the pixel of the equal-averaging method or the weighted averaging method. Figure 29 is 3
A convolution method with ×3 pixel references is shown. In this diagram,
The pixel whose brightness is to be determined is indicated by 2901.

The image continues to the bottom right of the diagonal line, and the sub-vixels painted in black are the sub-vixels that are counted. Each pixel is divided into 4*4. Therefore, in this case, a 12*12 filter will be used.

This method has the effect of removing high frequency components contained in a vector image.

On the other hand, a publishing system using parts del computers,
With the spread of so-called DTP (desk top publishing), systems for printing vector images, such as those used in computer graphics, have become widely used. A typical example is a system using Adobe's Post Script. PostScript is a page description language (Page Des
criptionL, anguage: Hereafter, PD
It belongs to a language genre called ``L'', and describes the contents of a single document, including the text (letter part), graphics, and their arrangement and appearance. It is a programming language for writing systems, and in such systems, the character fumen [・toshideherittle font is adopted 1-7
Therefore, even when characters are scaled, the print quality can be significantly improved compared to systems using bitmap fonts (for example, conventional word processors). It also has the advantage of being able to print a mixture of graphics and images.

And °Niroga1.゛The resolution of the laser printer used in these snooms is at most 240 dpi.
Many of them have a resolution of ~400 dpi, and similar to CRT displays of TV and graphics, there is a problem in that aliasing occurs due to the low resolution. For this reason,
17-The printing using a printer also requires anti-aliasing processing to improve the quality of the printed image.

[Problem that the invention attempts to solve]

However, in a graphic processing device applying the conventional anti-aliasing processing method, one pixel can be processed into multiple sub-vixels (for example, 49 sub-vixels).
In order to calculate the area ratio (brightness) by counting the number of sub-vixels filled in,
There was a problem in that the calculation took time, which hindered improvement in display speed or printing speed. In particular, the convolution method has the problem that it requires a large amount of calculation and affects multiple pixels, making it difficult to improve the processing speed.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to obtain the area ratio at high speed without having to perform subvixel division and counting the number of filled 62 pieces.

[Means to solve the problem]

In order to achieve the above object, the present invention adjusts the output of edge pixels of hector data based on the area ratio to be filled, and performs anti-aliasing processing to smoothly express jagged edges (aliases) of the output image. In the graphic processing device to be executed, there is provided an end point determination means for determining whether or not an end point of vector data exists within an edge pixel; an area ratio determining means that determines the area ratio to be filled in for the edge pixel based on the input/output coordinates of the edge part pixel; The present invention provides a graphic processing device equipped with end point area ratio setting means for setting.

[Operation] The graphic processing device of the present invention uses the end point determining means to determine whether an end point of vector data exists within an edge pixel. If there is no end point within the edge pixel, the area ratio determining means Q determines the area ratio to be filled in for the edge pixel based on the input/output coordinates when the vector data crosses the edge pixel. - When an end point exists in an edge pixel, the end point area ratio setting means sets a predetermined constant as the area ratio to be filled in for the edge pixel.

〔Example〕

Hereinafter, an image forming system incorporating the graphic processing device of the present invention as a PDL controller will be described as an example. roller(
The configuration and operation of the graphics processing apparatus of the present invention), the configuration of the image processing apparatus, (1) the configuration and operation of the multi-value color printer, and (2) the multi-value drive of the driver will be explained in detail in this order.

■Overview of anti-aliasing processing
), if there is no end point in the edge pixel, the area ratio is determined based on the input/output coordinates V when the hector data crosses the edge pixel. 17, so that anti-aliasing processing can be executed at high speed by setting a predetermined constant as the area ratio of edge pixels. Hereinafter, with reference to FIG. 1(a) to (d),
The principle of antialiasing processing, which is the main part of the present invention, will be explained in detail.

The details will be described later, but when vector data is input, the PDL controller 200 determines whether the element is a curved vector, and if it is a curved vector, it approximates it to a straight line vector and stores it in a predetermined work area as a straight line element (line). The linear elements in this work area are sorted by the starting X coordinate of the straight line (in other words, they are rearranged in the order of the scan lines), and then the filling process is performed for each scan line while performing the anti-aliasing process. When performing this filling process, first, in order to identify the edge pixels on the scan line to be processed and the image portion within the edge pixels, the X coordinate and edge information (left and right of the edge) of the edge pixels appearing on the scan line are identified. to a predetermined table (so-called AET: Active
Edge Table). In this example, when registering this AET, information on whether or not an end point exists within an edge pixel, and input/output coordinates (inside an edge pixel) when a straight line element (vector data) crosses an edge pixel are provided. (relative coordinates of) are registered in the AET along with the X coordinate of the edge pixel described above.

Specifically, the coordinates of the intersection between the linear element (vector data) and the target scan line are calculated, and the pixel where the intersection exists is defined as the edge pixel. Next, it is checked whether there is an end point within the edge pixel, or in other words, whether two linear elements (vector data) intersect within one edge pixel. If an endpoint exists, turn on the specified endpoint flag information
Make it.

If there is no end point, the input/output coordinates of the linear element (vector data) for that edge pixel are shown in Figure 1 (a).
As shown in , Xa)'o is calculated as a relative coordinate within the edge pixel based on the coordinate system. After that, the coordinates (X coordinates) of the intersection point and end point flag information.

Register input/output coordinates, etc. to AET.

Based on the AET information registered in this way, in the anti-aliasing process, if the end point flag information is ON, it is determined that an end point exists in the edge pixel,
A predetermined area ratio (for example, 6/9) is set as the area ratio of the edge portion pixels.

On the other hand, if the end point flag information is OFF, it is determined that there is no end point within the edge pixel, input and output coordinates of vector data are input from the AET, and the area ratio is determined by the following method.

The coordinates of the edge pixels are determined in advance as shown in Figure 1 (℃).
al, a2. a3. a4.・・・・・・Divide al2 into 12 input and output canilia, and create a LUT (
Create a Look Up Table. next,
Convert the input/output coordinates of the vector data to input/output canilia using the conversion table shown in Figure 1(d), and read the corresponding area ratio from the LUT described above using the combination of input/output canilia and edge type as keys. 0 For example, when the vector data crosses the edge pixel from the outgoing canilia a1 to the incoming and outgoing canilia a4, the area ratio is determined from the LUT to be r3/9J for the artificial edge and r9/9J for the right edge. Ru.

Note that this area ratio corresponds to the area ratio determined by 3*3 subpixel division (uniform averaging method).

In this way, if there is an end point in the edge pixel, a predetermined area ratio is set, and if there is no end point, the area ratio is easily calculated from the LUT using the input/output coordinates, and anti-aliasing processing can be performed at high speed. .

■Block diagram of the image forming system The image forming system of this embodiment uses the Page Description Language output from DTP (Desk Top Publishing).
e: hereinafter referred to as PDL language)) and image information read by an image reading device. The configuration of the image forming system of this embodiment will be described below with reference to FIG.

The image forming system includes a host computer 100 that creates a document written in PDL language (Postscript language is used in this embodiment);
A PDL controller (Graphic processing 7 of the present invention) that applies anti-aliasing processing to the PDL language sent page by page from 200, an image reading device 300 that reads image information via an optical system (7), and a PDL-1 (200);

An image processing device 400 inputs the image output from the image reading device 300 and performs image processing (details will be described later), and prints the multivalued image data output from the image processing device 400. Multivalued car juice-・1.・-The-
・Printer 500 and PDT-]tont 1 franc 200
, image reading device 30;], image processing device 400. and a system control section 600 that controls the value puller/laser printer 500.

■The configuration and operation of the PDL and controller are shown in Figure 3.
The configuration of the PDL language 200 is shown, and includes a receiving device 201 that receives the PDL language sent from the post-combination program 100;
A CP that performs storage control and anti-aliasing processing for the PDL language [J202, internal system buses 203 and 6, and internal system J5 bus 203 to be transferred from the receiving device 201 to i'Dl , a RAM 204 that stores language, a ROM 205 and 2 that stores anti-aliasing programs, etc., a memory that stores RGB image data of multiple four shifts subjected to anti-aliasing processing, and a paper memory. 2
06ζ-1 Transmission device 207 that transfers the stored RGB image data to the surface image processing device 4 O0 (Q2) and the I10 device 20 that performs sending and receiving (3) with the system control unit 600
It consists of 3.

Here, the CPU 2 O2 transfers the PDL language received by the receiving device 201 to the block 7gram δ stored in the ROMI 205, passes it through the internal system hash 203, and stores it in the RAM 2 O4. P for 1 vegetable
When the DL 3 words are received 1-1 and stored in the RAM 204, the RA is
Anti-aliasing processing is applied to the graphical elements in the M 204, and the multivalued RGB image 1-2 is stored in the block 1/- block memory section of the page memory 206 (page memory 2061, J:, R, GB blocks). (consisting of a memory section and a feature information memory section).

The date and evening in the base memory 20G are then sent to 3.
1. Through the device 207. and sent to the image processing device 400.

Hereinafter, with reference to FIG. 4(a), 0-)), P D
L. The operation of the controller 200 will be explained.

FIG. 4(a) shows a flowchart of the processing performed by the CP TJ 202. As mentioned above, the PDL controller 200 performs anti-aliasing processing on the PDL and language sent page by page from the host combination, and the first color is red (R).

A three-color image Q of H (G) and blue (B) is developed.

In P D i-language, graphics and characters are all-
As the name ``page description language'' suggests, the processing unit of image@information is handled in units of pages. Saraotsu 42, 1 page is 1
L7 is a bus composed of one or more elements (graphical elements and character elements), and is composed of at least one bus.

First, when you input the PDL language, it is determined whether the element is a curve or not, and if it is a curve vector, this is done.
is approximated to a straight line vector and registered as a straight line element (line) in the work area Q. Do this for all figures and characters 1 in one bus, and then create a work area for each bus.
・Register linear elements (processing 1).

And 1. The linear elements of the work area registered in units of two buses are sorted by the starting X coordinate of the straight line (processing 2).

Next, by process 3, update the X coordinate one by one)
, performs filling processing using scanning lines. For example, when performing the bus filling process shown in FIG. 4 (00), the element of the side across the scanning cotton 37C to be processed and the real value of the X coordinate across the scanning cotton yc (shown in FIG. 5). zuX1χ
2 X3 X4) and AET (Active Edge)
Table: A table that records the X coordinate of the edge that appears on the second scanning line)! Register here. Here, the order of the elements registered in the work area is the I registered in process 1.
@@! : Because it is, it is necessarily.

Also, the X coordinates that cross the scanning line) + When processed for the first time, X is first registered in the AET as the X coordinate of the edge portion appearing on the scanning line yc.Therefore, after registering the AET, the elements of each side in the AET are Sort in descending order. Then, leave the first two elements of AET bare and fill in the space between them (specifically, for example, fill in with the scan line formed by scan line yc and scan line yc+1) .

Anti-aliasing processing is achieved by adjusting the density and brightness of pixels in the edge portion in accordance with the area ratio in this filling processing. After that, move the processed side to A
Remove from ET, update scanline (update y coordinate), and A
Similar processing is repeated until all sides in ET are processed, in other words, until all elements in one bus are processed.

Above processing 1. Processing 2. The work in process 3 is executed pass by pass and repeated until all passes for one page are completed.

Next, FIG. 4(C) shows the AET registration and anti-aliasing processing executed during the scan line filling process of Process 3 described above.

This will be explained in detail with reference to the flowchart in (d).

Here, for example, in process 1 of FIG. 4(a),
), this figure has the following elements.

(b) Five line vectors AB, BC, CD, DE, and EA (represented by real numbers) (rl) Color and brightness values inside the figure This figure is created as shown in Figure 5 (b) by the above-mentioned operation. , into seven straight line vectors (expressed as real numbers) extending in the main scanning direction. At this time, in this embodiment, the following information is added to the starting points and ending points of the seven straight line vectors. That is, (c) the starting point coordinate value (
Real number expression) (d) Starting point and ending point of straight line vector (pixels in the center and center)
(f) Characteristic information of the starting point and end point (pixels in the center/edge part) of the straight line vector (right edge, left edge, end point flag information, line of 1 dot or less, etc.) (f) Straight line vector Input/output coordinates (relative coordinates within edge pixels) when a vector element crosses the start and end points (edge pixels) of

FIG. 4(C) is a flowchart showing AET registration in process 3. First, the X coordinate (intersection point) of a straight line element (vector data) that crosses the current scanning line (for example, scanning line yc) is calculated (5401). Next, an end point exists within the edge pixel that includes the X coordinate. Check if it does (5402),
If the endpoint exists, turn on the endpoint flag information (S40
3) On the other hand, if there is no end point, the input/output coordinates for the corresponding edge pixel of the straight line element are calculated as relative coordinates within the edge pixel (5404). The information in (a) to (f) described above is written into the AET (5405). The above processes 5401 to 5405 are performed for all linear elements (5406).

FIG. 4(d) is a flowchart showing the filling process using scan lines in process 3, in which anti-aliasing processing is performed based on AET information and pixels are filled.

First, refer to the end point flag information of the edge pixel (54
07), and when the end point flag information is ON, the predetermined value (6
;/9) as the area ratio 5408), and if the end point flag information is not ON, read the corresponding area ratio from the LUT based on the input/output coordinates of the edge pixel and set it as the area ratio of the edge pixel. (S409).

The above processes 5407 to 5409 are repeated until all edge pixels are completed (5410). Next, the area ratio is set to 1 for the non-edge pixels (pixels in the image area other than the edge pixels) (S411), the anti-aliasing process is completed, and the overwriting process (5412) is performed. Drawing is performed in the page memory (S413).

The area ratio of the figure in FIG. 5(a) obtained by the anti-aliasing process in this manner has a value as shown in FIG. 6.

Here, if the figure in FIG. 5(a) has a white background color (
The figure color is red (maximum brightness: 25) on top of (maximum brightness: 255)
5), from the area ratio k (see Figure 6), the brightness value of each color of the figure is 1< , , (red), , (green), Kb (blue) are as follows. 1, Kr ”' KII+Xk + K*zX(1k
) Kv = Kc + Xk + KGZX (1k)
Kb = Ks+×k + KIl□X(1-k
) However, 12, Kl! 11. KIλl+K,, respectively, indicate the brightness values of the colors (red, green, and blue, respectively) of the figure given by -to notation (n).
FIE does not show the brightness value of each previously painted color. Furthermore, K.
1, , K, , K- refer to the data in each plane memory section corresponding to RGB in the memory 206.

, -noyo) 72 to the calculated brightness value.

The brightness value of K is shown in FIG. 7(a) and (bL (c)r). It is stored as image data.For comparison, here is an RGB image without anti-aliasing processing.
The data are shown in Figures 8(a), (b), and (C).

0 Configuration of Image Processing Apparatus The configuration of the image processing apparatus 7400 will be described with reference to FIG.

The image processing device 400 is a CC in the image reading device 300.
BK is necessary for recording the three-color image signals read by D7r, 7g, and 7b.

Yellow (Y), magenta (M), and cyan (C)
Convert to each recording signal. In addition, the RGB image data given from the above-mentioned PI]-'' controller 200
・Yu is also black (BK), Yeo--(')/
), maginter (M), and cyan CC>. A mode in which image signals are input manually from the image reading device 300 is called a copying machine mode, and a mode in which RGB image data is input from the PDL fan Y roller 200 is called a graphics mode.

Image processing bag $400! ;! , CC07r, 7g, and 7b output signals are inputted with 8-bit A/D conversion, and the color gradation data is inputted, and the color gradation data is inputted, and the optical illuminance unevenness on the day and evening, and the internal of CCD7r, 7g, and 7b are input. A shading correction circuit 401 that performs correction for variations in sensitivity of terminal elements, etc.; color gradation data 1 or j output from the shading correction circuit 401; color gradation data (RGB image data) output from the PDL controller 200; ) is selectively output according to the above-mentioned mode.・Input the 8-bit data (color gradation data) output from Kuza 402 and Multib 1/Kuza 402, change the 7 gradation according to the characteristics of the photoreceptor, and set it to 6.
rII! output from datater 17! The 6-bint gradation data representing the gradations of (R), green (G), and blue (B) output from the positive circuit 403 and the γ correction circuit 403 are converted into complementary colors cyan (C) and magenta ( M).

Complementary color generation circuit 405 converts gray scale data (6 bits) of yellow (Y), etc., and a predetermined value for each gray scale data of Y, M, and C output from complementary color generation circuit 40 [5]. 1. A masking processing circuit 406 that performs the masking process and the Y, M, and C gradation data after the masking process are input to tJcR.
The tJcR processing/black generation circuit 407 executes processing and black generation processing, and converts each 6-bit gradation data of Y, MC1, and BK output from the JCR processing/black generation circuit 407 into 3-bit data. Floor construction! Synchronizes the gradation processing circuit 40B, which converts leap data Yl, Ml, CL, and BKI into multi-value color data and outputs it to the laser drive processing unit 502 inside the laser printer 500, and each circuit of the image processing device 400. and a synchronization control circuit 409 for

Although the details will be omitted, the γ correction circuit 403 has a configuration in which the gradation can be arbitrarily changed using the operation button I of the console 700.

In addition, the algorithm used in the gradation processing circuit 408 and 1
-2, the multi-value dither method, multi-value error diffusion method, etc. can be applied. For example, if the Y iser matrix of the multi-value dither method is 3X3, the number of gradations of the multi-value color laser printer 500 is This is the product of 3×3 area gradation and 3-bit (that is, 8 steps) -multilevel relay, and becomes 3×3×8=72 (3 rounds of floors).

Next 6. -, masking processing circuit 406 and UCR processing
The processing of the black generation circuit 407 will be explained.

Generally, the arithmetic expression for the masking process of the masking process circuit 406 is as follows: Y, , Mi, C,: Data before masking process Y, , M,
,C,: Data after masking processing Also, the arithmetic expression for UCR processing of the UCR processing/black generation circuit 407 is generally expressed as follows.

Therefore, in this embodiment, new coefficients are obtained from these equations using the product of both coefficients.

In this embodiment, a new coefficient (such as "allo") that performs this masking processing and UCR processing simultaneously is calculated and obtained in advance, and further, using the new coefficient, the masking processing circuit 4
06 scheduled input values Y,,M,.

Output value (y, °, etc.) corresponding to Ci (6 bits each)
A value that is the calculation result of the UCR processing/black generation circuit 407 is obtained and stored in a predetermined memory in advance.

Therefore, in this embodiment, the masking processing circuit 406 and U
The CR processing/black generation circuit 407 is composed of a set of ROMs, and the data at the address specified by the input \, M, and C of the masking processing circuit 406 is given as the output of the UCR processing/black generation circuit 407.

In addition, for boat fishing, the masking processing circuit 406 performs Y and M according to the characteristics of the spectral reflection wavelength of the toner for forming a recorded image.
, C signals, and the UCR processing/black generation circuit 407 performs correction for color balance in overlapping toners of each color. UCR processing/black generation circuit 4
07, black component data BK is generated by combining the input three color data of Y, M, and C, and the output Y,
The M and C color component data are corrected to values obtained by subtracting the black component data BK.

In the above configuration, the γ correction circuit 403 executes the process based on the T correction conversion graph shown in FIG. 10, and the complementary color generation circuit 405 executes the process as shown in FIG. 11(a).

Suppose that processing is executed based on the conversion graphs for complementary color generation shown in (b) and (C), and then the masking processing circuit 406 and the UCR processing/black generation circuit 407 execute processing based on the following equation. , FIG. 7(a).

The RGB image data shown in (b) and (C) is γ
Correction circuit 403. Complementary color generation circuit 405. Masking processing circuit 406. Then, through the UCR processing/black generation circuit 407, it is converted as shown in FIGS. 12(a), (b), (C), and (d).

Furthermore, if the gradation processing circuit 408 uses a Heyer type 3×3 multivalued dither matrix shown in FIG. 13, Y in FIGS. ,M
.

The data for C and BK are shown in Figure 14 (a) and (b), respectively.
, (C).

It is converted into the data shown in (d).

For comparison, when data without anti-aliasing processing (data in FIGS. 8(a), (b), and (C)) is processed by the image processing device 400, the first
It is converted as shown in Figure 5 (a), (b), (c), and (d).

■Multi-value puller ・1.・Configuration of the printer First, refer to the control program diagram shown in FIG.
Multivalued color! -1.-Explaining the general configuration of the printer 500 (1. Photosensitive drum), 1. The processing section 501 uniformly charges the surface of the photosensitive drum (to be described later) L7, and the charged surface with a laser beam. The recording paper C1 is exposed to light to form a latent image 5, and the latent image is developed with toner to form a recording paper C1. Developing/transfer section 50 Develops/transfers the K, 7, and C data. a cyan developing/transfer section 501m that performs development and transfer of M data, and a cyan development/transfer section 501y# that performs Y-day and evening development and transfer;
It is equipped with

The 1/-re'-drive mj processing unit 502 processes the three pixels (Y, M, C, BK) output from the image processing device 400 described above.
・It inputs data (in this case, image density data) and outputs a laser beam.
, a buffer memory 50 for inputting the 3-bit data and data of C.
3y, 503rn, 503c and corresponding to Y, M, C, BK respectively 18. Laser diodes 504y, 504m, 504c, 504 that output a t-day beam
bk, laser diode 504y, 504rrh,
504C, 5041)k, respectively.

In addition, the black developing/transfer section 5 of the photoreceptor development processing section 501
01bk, the laser drive processing section 502, the laser diode 504bk, and the driver 505bk. l/
-Zer diode 504c, driver 505c,
The combination of buffer memory 50 and '3c is connected to cyan recording unit CU (see Fig. 17), magenta developing/
Transfer section 501m, laser dyemate 504m,
The combination of the driver 505m and the buffer memory 503m is the combination-14 of the magenta recording unit l-MU (see FIG. 17), the yellow developing/transfer section 501y, the laser diode 504y, the driver 505y, and the 9-buffer memory 503y. - Yellow distribution uni, 1
- Called YLJ (see Figure 17). , -Each of these 2I
As shown in the figure, there are black recording units l-B K tJ , cyan recording units , from the recording paper conveyance direction around the pulse feeding heald 50 ( 3 ) that conveys the recording paper.
]・CU, “7 Zenta Record F~NitsutM1no, Yett
The records are arranged in the following order: Konyn + - Y tJ.

With this arrangement of each recording unit I, exposure starts first. i laser daio F 504 b k for black exposure, and for yellow exposure).

/- data iode 504y will start exposure after 1. Therefore, there is a time difference in the order of exposure start between each [/-day diode, and in order to hold recorded data (output of the image processing device 400) during the time difference, 1/-the-...
- The drive processing unit 502 is equipped with the aforementioned three buffer memories 503y, 503m, and 503c.

Next, the configuration of the multivalued color laser printer 500 will be specifically explained with reference to FIG.

The multivalued color/-day printer 500 has a 50G conveyor blade that conveys the recording paper, and a conveyor belt 506 as described above. , ′-each arranged recording unit t
-Y t, J, M tJ, C[J, B K
507a, 507
m paper 7J0508 a, 508 which sends out one recording paper each from [b and paper feed force cera) 507a, 5071]
b, and the recording paper sent out from the paper feed trays 1507a, 5071) are aligned by the roller 509 and the conveyor I, 5 (]6, L unit BK, I, CU. , Mi, J, and YtJ, and fixes the transferred image on the recording paper.
10, 5, and a paper discharge flow 511 for discharging recording paper to a predetermined discharge section (not shown). Here, each recording unit Y(), M(J, CU, BKl, J is a photosensitive drum 512y, 512m, 512c, 512bk, and a photosensitive drum 512y, 512m, respectively.

Charger 513y that uniformly charges 512c and 512bk
, 51:3rn, 513e, 513bk and 2. The photosensitive drums 512y, 512m, 512c, and 512bk are
- borigon mirror 514y, 5 for guiding the day beam;
14m, 514c, 514bk and motor 515y, 5
15m, 515c, 515bk, and photosensitive drum 512
toner developing devices 516y, 516m, 516c, 516 that develop the electrostatic latent images formed on y, 512m, 512c, 5f2bk using toners of corresponding colors, respectively;
bk, transfer chargers 517)', 517m, 517c, 517bk for transferring the developed toner image onto recording paper, and photosensitive drums 512ff, 512m, 512c, after transfer.
Cleaning devices 518y and 518m remove toner remaining on 512bk.

It consists of 518c and 518bk. In addition, 519y
, 519m, 519c, and 519bk respectively indicate CCD line sensors for reading predetermined patterns provided on the photoreceptor drums 512y, 512m, 512C, and 512bk. - Detects the process status of the printer 500.

In the above configuration, the operations of the yellow recording unit YU will be explained using exposure, development, and transfer as examples.

FIG. 18(a), et al) shows the yellow recording unit YU (7).
)G shows the structure of the tip yarn. In the figure, a laser beam emitted from a laser diode 504y is reflected by a polygon mirror 514y, passes through an f-theta lens 502y, and then passes through a mirror 521y.

522y and is irradiated onto the photosensitive drum 512y through the dustproof glass 523y. At this time, since the polygon mirror 514y is rotated at a constant speed by the motor 515y, the laser beam moves in a direction along the axis of the photosensitive drum 512y (main scanning direction). Furthermore, in this embodiment, a photosensor 524y is provided to detect the base point for tracking the scanning position of the main scan, so that the laser beam at the non-exposed position is detected. The laser diode 504y outputs recording data (
Since the photoreceptor drum 504y is activated to emit light based on the 3-bit data from the image processing device 400, multivalue exposure corresponding to the recording data is performed on the surface of the photoreceptor drum 504y. The surface of the photosensitive drum 504y is uniformly charged in advance by the charger 513y as described above, and an electrostatic latent image corresponding to the original image is formed by the exposure. The electrostatic latent image is developed by a yellow developing device 516y to become a yellow toner image. This toner image is transferred from the cassette 507a (or 507b) to the paper feed roller 50, as shown in FIG.
8a (or 508b), and is transferred by a registration roller 509 onto a recording sheet conveyed by a conveyor belt 506 in synchronization with the formation of a toner image of the black recording unit (BKU).

The other recording units BKU, CU, and MU have similar configurations and perform similar operations, but the black recording unit BKU is equipped with a black toner developing device 516bk and forms and transfers a black toner image, and the cyan recording unit C
U is equipped with a cyan toner developing device 516C, which forms and transfers a cyan toner image, and a magenta recording unit) M
U includes a magenta toner developing device 516m, which forms and transfers a magenta toner image.

■The multi-value drive drivers 505y, 505m, 505c, and 505b are as follows:
Y sent from the image processing device 400.

Based on the 3-bit data of M, C, BK, the corresponding laser diodes 504)', 504m, 504c, 5
It performs control for multi-value driving of 04bk,
As the driving method, power modulation, pulse width modulation, etc. are generally used.

Hereinafter, multi-value drive by power modulation applied in this embodiment will be explained in detail with reference to FIGS. 19(a), (b), (C), and (d). In addition, drivers 505y, 505m
.

505c, 505b, and laser diode 504
y, 504m, 504c, and 504bk each have the same configuration, so here, the driver 505y and laser diode 504y will be explained as an example.

As shown in FIG. 19(a), the driver 505y turns the laser diode 504y on and off based on a predetermined LD drive clock.
n10ff circuit 550 and 3-bit image density data (
Here, input the Y data) from the analog signal G, the D/A converter 551, and the image density value 1. , a constant current circuit 552 that supplies the current (ID drive current) Id for driving the l/-day diode 504y to the laser... diode on, 10ff circuit 550.
It consists of

Here, the LD dry black is turned on at ``1''.
It is defined as off at P0'', and L' is defined as off in Fig. 19(b).
C = , + , = Zade Od o n / o
f f circuit 550L turns off the ζ laser diode 5043T according to this. , also i, -D
Since the drive current 1d and the laser beam power are in a proportional relationship, based on the image density data value <LD drive voltage 1°Id is generated, and - is 4, and the image density data value is Is it possible to obtain the corresponding lz-device output? 1
This will happen. For example, as shown in FIG. 10 (1), the direct image density data is '4'' (Telegraph N-1 in the figure).
) in case of 11 years old, constant current circuit 12 according to 52. The corresponding LD drive shaft current It1 is supplied at 1.・~11 of day diode 504y. -D beam power is level 4 6 Also, the image density data value is °7'"
In the case of (D/N in the same figure)? , constant current circuit 5
Corresponding I and D drive currents Id are supplied by 52,
Laser beam power of laser diode 504y
- becomes I,...Bell 7.

Next t,': Referring to FIG. 19(C), the diode on10ff circuit 550. D/A converter 5
51 and a specific circuit configuration of the constant current circuit 552. The laser diode on10ff circuit 550 is
TTL, impark 553, 554, and differential switching circuit 555, 55 that performs onloff toggle operation
6, when VG1>VG2, the differential switching circuit 555 is on, and the differential switching circuit 55G is off.
f f, 1 when VGI<VG2, the differential switching circuit 555 is off.

a resistor R2 forming a voltage dividing circuit that generates vc2 that satisfies the conditions for the differential switching circuit 5156 to be turned on;
It is composed of Ri. Therefore, L D dry
When the voltage is 1''', the output of the inmater 554 is V
GI is generated 5, and the above q・- items (V('; 1 > VG
2)? A foot 17, difference @3j type switching circuit: 35
5 is on, differential switching circuit 55 (3 is off, and the laser diode F 504 y is turned on.

Conversely, when the LD drive clock is °O゛, -
, since there is no output from the in-hark 554, the above condition (VG
I<VG2), and the differential switching circuit 555
is off, the differential type switch is off, and the differential type switch is on.
504y is turned off.

To D/8: The inverter 551 has a launch 557 that latches the input image density data while the LD drive clock is 1", and a V rat that provides the maximum output value V rsf.
generator 558, image density data and maximum output (MV,
, 3 pins that output analog data Vd based on f)
The relationship between Vd, the image density data, and the maximum output value .

Constant current circuit 5 (52 is described above),
It supplies a current of 504 V to the laser diode on10ff circuit 550,
It is composed of transistors 560 and 1 and resistors R4 and R. The analog output Vd of the D/A converter 551 is applied to the base of the transistor 560 and determines the voltage applied to the resistor R4.In other words, the current flowing through the resistor R6 is approximately equal to the collector current of the transistor 560, so Vd By 1.・-Dedio Do5
The current 1d flowing to 04 V is controlled.

FIG. 19(d) shows the output of the latch 557 mentioned above.

This is a timing diagram showing the relationship between VGI, Vd, and Id. Here, Vd is based on the image density data (8 gradation data of 3 binoto data 20 to 7), ■r□×
Takes the value in 8 steps from o77 to 7/7, and if Id, this Vd
Based on the value of , there are eight levels from 10 to 17.

The laser diode 5°4y forms a latent image on the photoreceptor drum 512y as shown in FIG. form.

In the image forming system to which the anti-aliasing processing and the apparatus of the present invention are applied, the toner image shown in FIG. 21 is finally created for the pentagon ABCDH shown in FIG. 5(a) by the above-described configuration and operation. Formed on recording paper. -Resolution of laser printer for boat fishing is 240~
Considering that it is 400 dpi, the density of the edge portion of the figure becomes visually lighter due to the anti-aliasing process. FIG. 22 shows a toner image of pentagon ABCDH when anti-aliasing processing is not performed.
As is clear from a comparison between the figure (toner image of the present invention) and FIG.
becomes visually smoother.

Further, in this embodiment, multi-value driving using power modulation is applied, but it goes without saying that similar effects can be obtained by using multi-value driving using pulse width modulation.

For reference, FIG. 23 shows the change in latent image form depending on the level of pulse width modulation, and also shows the toner image when pulse width modulation is applied to the pentagonal ABCDH shown in FIG. 5(a). It is shown in FIG.

〔Effect of the invention〕

As explained above, the graphic processing device of the present invention adjusts the output of the edge portion pixels of vector data based on the area ratio to be filled, and adjusts the output of the edge portion pixels of the output image (
In a graphic processing device that performs anti-aliasing processing to smoothly express an alias (alias), an end point determination means for determining whether an end point of vector data exists within an edge pixel, and a case where an end point does not exist within an edge pixel. ,
an area ratio determining means for determining an area ratio to be filled in for an edge pixel based on input/output coordinates when vector data crosses the edge pixel; Since the end point area ratio setting means is provided to set a predetermined constant as the exponent area ratio, the area ratio can be obtained quickly without dividing subpixels and counting the number of filled pixels.

[Brief explanation of drawings]

FIGS. 1(a) to (b) are explanatory diagrams showing the principle of anti-aliasing processing in the graphic processing apparatus of the present invention, FIG. 2 is an explanatory diagram showing the configuration of the image forming system of this embodiment, and FIG. An explanatory diagram showing the configuration of a PDL controller (graphic processing device of the present invention), FIG. 4(a) is a flowchart showing the operation of the PDL controller, FIG. (C) is a flowchart showing AET registration, FIG. 4(d) is a flowchart showing anti-aliasing processing in fill processing using scan lines, and FIGS. 5(a) and (b) are explanations showing linear vector division of a figure. Figure 6 is an explanatory diagram showing the area ratio after anti-aliasing processing, Figure 7
Figures (a), (b), and (C) are explanatory diagrams showing RGB image data stored in the brain memory section of the page memory. FIG. 9 is an explanatory diagram showing the configuration of the image processing device;
FIG. 10 is an explanatory diagram showing the conversion graph for T correction of the T correction circuit, and FIGS. 11(a), (b), and (C) are explanatory diagrams showing the conversion graph for complementary color generation used in the complementary color generation circuit. 1
Figures 2 (a), (b), (C), and (d) are shown in Figure 7 (
An explanatory diagram showing the state in which the RGB image data shown in a), (b), and (C) is output from the UCR processing/black generation circuit. Explanatory diagrams shown in Fig. 14 (a), (b),
(C), (d) are shown in Figure 12 (a), (b), (C
), (d) An explanatory diagram showing the state in which the Y, M, C, BK data is converted by the gradation processing circuit, FIG. 15 (a)
, (b), (C), (d) are shown in Figure 8 (a), (
Fig. 16 is a control block diagram showing a multi-value color laser printer, and Fig. 17 is an explanatory diagram showing the state in which the data in b) and (C) are processed by an image processing device. Explanatory diagram showing the configuration, FIGS. 18(a) and (b) are explanatory diagrams showing the configuration of the exposure system of the yellow recording unit, and FIGS. 19(a), (b), (C)
, (d) is an explanatory diagram showing multi-value drive by power modulation,
Fig. 20 shows the state of the latent image depending on the power modulation level.
FIG. 22 is an explanatory diagram showing the final toner image of the pentagons A B C D E shown in FIG. , Figure 23 &! , 7. of gh during the pulse. □ Shows the state of the latent image due to <! '-Explanation 4, Figure 24 is 5I
M(a)ζ4showj7I]gon AB(-”D F, &
FIG. 25(a) is an explanatory diagram showing a toner image when pulse modulation is applied; (13) is an explanatory diagram showing a conventional anti-aliasing process; FIG. 26(a); ([]) is an explanatory diagram illustrating the uniform averaging method (, knee,,,,,,5,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, respectively,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,0,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
13) is the weight I (1-digit averaging method).Explanatory diagram showing the aliasing process.
), (C), and (d) are explanatory diagrams showing examples of filters using the weight averaging method. Figure 29 is: 3 x 3
FIG. 3 is an explanatory diagram showing a convolution method with reference to a pixel. Explanation of symbols 100 Host computer 200 - PDL, controller 201 ---- Receiving device 202 ----, CPU O
O Internal system bus RAM 205----, ROM page memory 20゛7--------- Transmitting device I10 device Image reading device Image processing device Multi-level color 1/-day printer system control unit

Claims (1)

[Claims] A graphic processing device that adjusts the output of edge pixels of vector data based on the area ratio to be filled, and executes anti-aliasing processing to smoothly express jagged edges (aliases) of an output image. An end point determining means for determining whether or not an end point of vector data exists within the edge pixel, and an input point when the vector data crosses the edge pixel if the end point does not exist within the edge pixel. an area ratio determining means for determining an area ratio to be filled in the edge pixel based on the output coordinates; and when an end point exists in the edge pixel, a predetermined constant is set as an area ratio to be filled in the edge pixel; 1. A graphic processing device comprising: end point area ratio setting means for setting an end point area ratio.