JPH0670097A - Picture reader - Google Patents

Abstract

PURPOSE:To satisfactorily read even a lustrous original. CONSTITUTION:This reader reads the picture information of the original by irradiating light on the original and detecting the reflected light and is provided with a light source for irradiating the light on the original, a first photosensor 11 for detecting normal reflected light components 7 from the original and a second photosensor 17 for equalizing the incidence angle (a) and outgoing angle (b) of the light from the light source 5 and detecting positive reflected light components from the original in the case of the original provided with a lustrous picture surface. Then, when the original is provided with the lustrous picture surface, correction for which the sensor output of the first and second photosensors is mutually synthesized by a prescribed method is performed and a detected result is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine and a color FAX.
And the like, the present invention relates to an image reading apparatus for reading image information of the original by irradiating the original with light and detecting the reflected light, and in particular, image reading capable of satisfactorily reading even an original having a glossy image surface. Regarding the device.

[0002]

2. Description of the Related Art Generally, in a copying machine, a color fax machine or the like, an image surface of a document placed on a contact glass is scanned while being irradiated with light from a light source, and the reflected light is scanned by an optical imaging element and an optical sensor. An image reading device is provided for reading the image information of the document by detecting the image information. As an example of such an image reading device, Japanese Patent Application Laid-Open No. Sho 61-61 is known.
A configuration in which an optical image forming body, a photoelectric conversion element, a light emitting element, and the like disclosed in "Image Input Device" of Japanese Patent Application Laid-Open No. 224769- are provided on a carriage and an image signal from the photoelectric conversion element is transmitted to a processing circuit by light. And the actual Kaihei 2-14366
The one disclosed in "Optical reader" of Japanese Patent Publication No. 6 which is composed of a converging optical transmission medium array (selfoc lens), a light source, and an optical sensor (CCD), and is provided with an antireflection mask near the document surface. Are known. However, in the conventional image reading apparatus as described above, although a good image can be read for a normal document, when reading a document having a glossy image surface, the glossy image surface is irradiated by the light source. Since the light is specularly reflected, the reflected light hardly reaches the optical imaging element and the optical sensor, and the output of the optical sensor is extremely lowered, so that the image information cannot be read at all.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional problems, and provides an image reading apparatus capable of satisfactorily reading an original having a glossy image surface. Has an aim.

[0004]

To achieve the above object, the present invention provides:
In an image reading device that reads the image information of the original by irradiating the original with light and detecting the reflected light,
A light source for irradiating the original with light, a first optical sensor for detecting a normal reflected light component from the original, and a second optical sensor for detecting a specularly reflected light component from the original having a glossy image surface. When the original has a glossy image surface, correction is performed to combine the sensor outputs of the first and second optical sensors by a predetermined method to obtain a detection result. Is characterized by.

According to the above-mentioned structure, in addition to the first optical sensor for detecting the normal reflected light component from the original, the second optical sensor for detecting the regular reflected light component from the glossy original is provided. In the case of a glossy original, correction is performed so that the values of the first and second optical sensors are combined with each other by a predetermined method, so that a glossy original can be read well.

An embodiment of the image reading apparatus of the present invention will be described below. FIG. 1 is a block diagram of an image reading apparatus embodying the present invention. In FIG. 1, this image reading apparatus includes a light source 5 (fluorescent lamp, halogen lamp, etc.) for irradiating an image surface of a document 3 placed on a contact glass 1 with light 4, and a light source 5 for emitting light from the image surface. Normal reflected light component 7
A first unity-magnification imaging element 9 (Selfoc lens) and a first unity-magnification optical sensor 11 for imaging and detecting light, and light 4 from the light source 5 when the image surface is glossy. Regular reflection light component 1 which is emitted to the opposite side at the same emission angle b as the incident angle a of
It has a second unity-magnification imaging element 15 and a second unity-magnification optical sensor 17 for imaging and detecting 3. And
The image reading apparatus further includes, as shown in FIG. 2, a line buffer memory 19 for holding sensor outputs from the first and second unit magnification photosensors 11 and 17, and a line buffer memory 19 from the line buffer memory 19. Based on the sensor output, the processing circuit 21 performs a predetermined correction when the sensor output of the first equal-magnification optical sensor 11 falls below a predetermined reflectance threshold level, as will be described later. The light source 5, the first equal-magnification imaging element 9, the first equal-magnification optical sensor 11, the second equal-magnification imaging element 15, and the second equal-magnification optical sensor 17 are mounted on a carriage (not shown). The image surface of the original is scanned by the movement of the carriage.

Next, the operation of this image reading apparatus will be described. First, the original 3 is placed on the contact glass 1, the image surface of the original is illuminated by the light source 5, and the normal reflected light component 7 is converted by the first equal-magnification imaging element 9 into the first equal-magnification light. An image is formed on the sensor 11, the reflected light component 7 is detected, and the specular reflected light component 13 is imaged on the second equal-magnification optical sensor 17 by the second equal-magnification imaging element 15, and the specular reflected light component is formed. 1
3 is detected. Here, when the image surface of the original 3 is not glossy, as shown in FIG. 3, the sensor output of the first equal-magnification photosensor 11 has not dropped below a predetermined threshold level. Reference numeral 21 outputs only the sensor output of the first equal-magnification optical sensor 11 read from the line buffer memory 19 as a detection result.

When the image surface of the original 3 has a gloss, as shown in FIG.
Sensor output of the second equal-magnification optical sensor 17 is lower than the predetermined threshold level, and the sensor output of the second unit magnification photosensor 17 is higher than the predetermined threshold level, the processing circuit 21 causes the line buffer memory 19 to operate. The portion other than the image information in the sensor output of the second equal-magnification photosensor 17 read further is set as the background level, and the output H ₁ of the image information portion in the sensor output of the second equal-magnification photosensor 17 is set. A predetermined correction is performed with the value (the value shown by the dotted line in FIG. 4) obtained by adding the output H ₂ of the image information portion of the sensor output of the first equal-magnification photosensor 11 as the image information level. The correction result is output as the detection result.

It should be noted that the first equal-magnification sensor 11 and the second equal-magnification sensor 17 have the same density, so that when the original is partially glossy as shown in FIG. However, since the positions of the sensors in the main scanning direction are similar, partial correction is possible.

In addition to accurately correcting the original density for each pixel as described above, prescanning is performed to roughly understand the glossiness of the original (depending on the ink characteristics of the paper),
Even if only a rough correction based on the correction data is performed, the reading performance is improved as compared with the conventional reading device. Further, since the specular reflection component causes glare other than the original and the correction becomes troublesome, it is effective to detect it through a polarizing plate. Further, when the reflection components from the document surface are detected by a plurality of sensors at different angles, the correction becomes more accurate. Further, according to the image reading apparatus of the present invention, it is possible to detect the specular reflection component (for example, due to the contact glass) which is generated other than the original document, so that the image quality is improved by performing the correction in consideration of the specular reflection component. There is also an effect to do.

[0011]

As described above, according to the present invention, in addition to the first optical sensor for detecting the normal reflected light component from the original, the second optical sensor for detecting the regular reflection light component from the glossy original is provided.
If a glossy original is provided with the optical sensor of
Since the correction is made by synthesizing the values of the second photosensor and the value of the second photosensor by a predetermined method, a glossy original can be read well.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an image reading apparatus embodying the present invention.

FIG. 2 is a configuration diagram of a correction unit of the image reading apparatus shown in FIG.

FIG. 3 is an explanatory diagram showing an optical sensor output during normal document reading in the image reading apparatus shown in FIG.

FIG. 4 is an explanatory diagram showing an optical sensor output when a glossy original is read by the image reading apparatus shown in FIG.

FIG. 5 is an explanatory diagram showing a read density when a document partially has gloss.

[Explanation of symbols]

1 contact glass, 3 originals,
4 irradiation light, 5 light source,
7 Normal reflected light component, 9 1st unit-magnification imaging element, 11 1st unit-magnification optical sensor,
13 specular reflection light component, 15 2nd unit-magnification imaging element,
17 second unit light photosensor, 19 line buffer memory, 21 processing circuit,

Claims (2)

[Claims] 1. An image reading device for irradiating a document with light and detecting the reflected light to read image information of the document, comprising a light source for irradiating the document with light and normal reflection from the document. An image reading apparatus comprising: a first optical sensor unit for detecting a light component; and a second optical sensor unit for detecting a specularly reflected light component from a document having a glossy image surface. 2. A correction means for correcting the image reading device to combine the sensor outputs of the first and second photosensor means with each other by a predetermined method when the original has a glossy image surface. The image reading apparatus according to claim 1, further comprising: