JPS63240260A - Picture reader - Google Patents

Abstract

PURPOSE:To miniaturize the entire reader by storing a data representing each effective picture element area of plural photoelectric conversion means tentatively and controlling a picture data stored in a line memory based on the data. CONSTITUTION:Two CCD linear image sensors 116 are arranged in a line to provide a part subjected to photodetection duplicatedly and a refllfected light of an original is subjected to photoelectric conversion one by one line each. A memory control circuit 120 extracts a part of an optically low reflectance in reading a reference face of shading correction to control a read address of a line memory 119 based on the data. Thus, data of the line memory 119 connected to the output of two A/D converters 118 are read properly to obtain an output converting an original picture into an electric signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image reading device that optically reads an image of a document, and more particularly relates to an image reading device that reads an image of a document using a plurality of photoelectric conversion means. It is something.

2. Description of the Related Art In recent years, there has been an increasing trend in the number of devices such as facsimile machines and copying machines employing an electrophotographic method that convert images of original documents into digital signals and read them.

An example of the conventional image reading device as described above will be described below with reference to the drawings.

FIG. 4 is a diagram showing a schematic configuration of main parts of a conventional image reading device. In FIG. 4, 101 is an original to be read, 102 is a fluorescent light for irradiating light onto the surface of the original to be read, 103 is a reflection plate for concentrating the luminous flux of the fluorescent lamp 102, and 104 is an original for reading the original 101. An optical mirror for guiding the reflected image and making it incident on the optical lens 105; 106 is a photoelectric conversion element such as a COD for converting the reflected image of the original 101 formed by the optical lens 105 into an electrical signal; , 107 is a sensor drive circuit for providing a driving clock signal etc. to the photoelectric conversion element 106;
108 is an A/D converter for converting the analog electrical signal of the photoelectric conversion element into a digital electrical signal; 109 is an A/D converter;
a line memory for storing the output of the D converter 10B;
1) 0 is a memory control circuit for controlling input and output timing of the line memory 109 and obtaining image data output.

The operation of an example of a conventional image reading device configured as described above will be described below.

First, light emitted from a fluorescent light 102 is irradiated onto the surface of a document 101 to be read, and the reflected light is incident on a photoelectric conversion element 106 by an optical mirror 104 and an optical lens 105.
Form an image. At this time, the original 101° and the fluorescent light 102. The optical mirror 104 has the same length as long as possible in the depth direction of the drawing, and the focal length of the optical lens 105 and the optical distance from the photoelectric conversion element 106 to the original 101 are set at an optically optimal position. It is something that is maintained in a relationship. The photoelectric conversion element 106 successively converts and outputs the reflected image of the original 101 into an analog electrical signal in response to a clock signal provided by the sensor drive circuit 107. As shown in FIG. 5, the analog electrical signal 124 output from the photoelectric conversion element 106 has a high output when reading a portion of the document 101 with a large amount of reflected light, that is, a portion 121 where the document image 125 is white. 1
25 is configured so that when reading a black part 122, the output is low, and when reading a gray part 123 of the document image 120, the output is an intermediate value. The output can be changed analogously. Analog electrical signal 124 is input to A/D converter 108 and sequentially converted into a digital signal.

The digitized signal is stored in the line memory 109 to be saved or reused. line memory 10
9, the image of the original 101 and the contents of the line memory 109 are configured to maintain a positional correlation with each other by the memory control circuit 1)0, and when the stored contents are reused, It is possible to generate image data only by controlling the memory control circuit 1)0 (for example, Japanese Patent Laid-Open No. 61-201559).

Problems to be Solved by the Invention However, the above configuration has the drawback that a high resolution image cannot be obtained unless a photoelectric conversion element with a large number of pixels is used. Furthermore, if the size of the original is equivalent to A3 size, it is necessary to use a large-diameter imaging optical lens, which has drawbacks from both a structural and cost perspective, making it impractical for practical use. had the problem of being unsuitable.

In view of the above-mentioned problems, the present invention reads an image of a document using a plurality of photoelectric conversion means, the imaging optical lens is relatively inexpensive, and the photoelectric conversion means can be used for general purposes, making the apparatus compact as a whole. This provides an inexpensive image reading device.

Means for Solving the Problems In order to solve the above problems, the image reading device of the present invention includes a light source that irradiates a document with light, and at least two or more light sources that receive reflected light from the document and convert it into an electrical signal. an imaging optical system for inputting reflected light from a document into the photoelectric conversion means; an analog-to-digital conversion means for converting the analog output of the photoelectric conversion means into digital data; It is equipped with a plurality of line memories for storing, a memory control means for controlling the output of the line memory, and a sensor control means for driving the photoelectric conversion means, and the plurality of photoelectric conversion means are arranged on one line from each other. They are lined up and photoelectrically convert the reflected light from the original one line at a time, and photoelectrically convert the reflected light from the original into a line. Sequential analog output for each
Input to digital conversion means. Further, the plurality of photoelectric conversion means each have a portion that receives reflected light from the document in an overlapping manner, and the memory control means controls each effective pixel area for an image read in the overlapping light-receiving portion. The memory control means includes a comparison means for determining the contents of the line memory, an address generation means for reading the contents of the line memory, an output of the address generation means, and an output of a plurality of photoelectric conversion means. In order to read the image on the document surface, it reads a reference surface having optically high reflectance for shading correction, and a means for controlling the connection of one line of read image. The reference surface having a high optical reflectance has a structure having a portion having an optically low reflectance for approximately displaying a connected portion of an image read by a plurality of photoelectric conversion means.

Effect of the present invention With the above-described configuration, in order to read an image on a document surface using a plurality of photoelectric conversion means, a reference surface having an optically high reflectance for shading correction is read in advance, and an image read by a plurality of photoelectric conversion means is read. In addition to having an optically low-reflectance portion for approximately displaying the connecting portion on a reference surface having a high reflectance, the data indicating the effective pixel area of each of the plurality of photoelectric conversion means is temporarily stored. The image data stored in the line memory is controlled based on the data.

Embodiment Hereinafter, an image reading apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration of the main parts of an image reading apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram showing the circuit block part of FIG. 1 in more detail. Hereinafter, in FIGS. 1 and 2, 101 is a document to be read, 102 is a fluorescent light to irradiate light onto the surface of the document to be read, and 103 is a reflector plate to concentrate the luminous flux of the fluorescent light 102. , 104 is an optical mirror for guiding the reflected image of the original 101 and making it incident on the optical lens 1) 5. 1) 6a and 1) 6b are electrical mirrors for guiding the reflected image of the original 101 formed by the optical lens 1) 5. A CCD-dimensional image sensor 1) 7 for converting into a signal is a CCD-dimensional image sensor 1) 6
a, 1) Sensor drive circuit for giving clock signals, reset signals, etc. for driving to 6b, 1) 8a and 1)
8b is a CCD-dimensional image sensor 1) 6a and 1) 6b
A/D converter for converting the analog electrical signal outputted by into a digital electrical signal, 1) 9 o a, 1) 9
e a.

1) 9ob and 1) 9eb are A/D converters 1) 8a.

1) Line memory for storing the output of 8b, 120
is line memory 1) 9oa, 1) 9ea.

This is a memory control wholesale circuit that controls the input and output timing of 1) 9ob and 1) 9eb to obtain image data output.

The memory control circuit 120 includes an edge detection circuit 130 for extracting an optically low reflectance portion when reading a reference surface for shading correction, and an edge detection circuit 1.
30 command outputs 16 cause line memory 1) 9 o
a, 1)9 e a, 1)9 o b.

1) Line memories 1) 9oa, 1) 9ea according to the output signals of the address control circuit that controls the read address of 9eb and the edge detection circuit 130.

1) Generate address control signals of 9ob, 1) 9eb,
Line memory 1) 9oa, 1) 9ea.

The output switching circuit 132 selects the output of 1) 9ob, 1) 9eb, and the line memory 1) 9oa, 1) 9ea, 1) 9ob by the output of the output switching circuit 132.

1) It is composed of a switch circuit 134 for switching the 9eb data output and passing the signal, and an output synthesis circuit 133 for finally obtaining the image data output.

The operation of the image reading apparatus configured as described above will be described below with reference to FIGS. 1, 2, and 3.

First, FIG. 3 is a diagram showing the timing relationship of the main parts in FIG.
The part containing 1), that is, the reflected light in the reading range of 1) 6a, is converted into an analog electrical signal and output, and the A/D converter 1) 8a
Enter. Next, the low reflectance portion 141 of the reference surface 140
The photoelectric conversion element 106b reads the 1) 6b reading range from the point including the
) Input an analog electrical signal to 8b.

A/D converter 1) 8a is C0D-dimensional image sensor 1
) 6a output is sequentially converted into a digital signal 10 and inputted to line memories 1) 9oa and 1) 9ea. Line memories 1) 9oa and 1) 9ea are A/D converters 1) 8a
The output signal of is divided into odd and even numbers and input.

Therefore, the outputs 12 and 13 of the line memories 1) 9oa and 1) 9ea respectively output read signals of the reference plane 140 at different timings. In the same manner as described above, the output of the CCD-dimensional image sensor 1) 6b is controlled by the A/D converter 1) 8b and the line memories 1) 9ob and 1) 9eb to produce outputs 14 and 15 at the timing shown in FIG. 3. It becomes a signal. The Esoji detection circuit 130 uses the line memory outputs 12.13° and 14.15 to detect the reference plane 14.
The left edge of the low reflectance portion 141 of 0 is detected and an edge signal is output. The address switching circuit 131 selects the line memo by the edge signal I6.
9 e a.

It controls the data reading address signals of 1) 9ob and 1) 9eb, and outputs the sensor switching signal 17 that controls the output switching circuit 132. The switch circuit 134 is controlled by the sensor switching signal 17, and the output combining circuit 1
33, line memory outputs 12, 13, 14.15 are the first signal of output 12, the first signal of output 13, the first signal of output 12
The second signal of output 14 is switched from the final valid signal of output 13 to the first valid signal of output 14, and then the first valid signal of output 15 is inputted in order. signal.

A second signal at output 14, a second signal at output 15.

The information is input in the following order. The output synthesis circuit 133 is capable of outputting line-shaped reflected images simultaneously read by the two CCD-dimensional image sensors as electrical signals in a format along the image of the original.

As described above, according to this embodiment, two C0D-dimensional image sensors are arranged in a line, have portions that receive light overlapping each other, and photoelectrically convert the reflected light from the original one line at a time. The output of each pixel of the image sensor is sequentially converted from analog to digital, and the output of the A/D converter for each pixel is input to the line memory, and the memory control circuit controls the address signal for reading data from the line memory. By appropriately reading data from the line memory connected to the outputs of the two A/D converters, it is possible to obtain an output in which the original image is converted into an electrical signal.

In addition, in the embodiment, the CCD-dimensional image sensor and A
Although a block diagram in which the A/D converter is directly connected is shown, it is clear that an amplifier circuit or a noise removal circuit may be used as a typical electric circuit to input the signal to the A/D converter.

Effects of the Invention As described above, the present invention includes a light source that irradiates an original, at least two or more photoelectric conversion means that receives reflected light from the original and converts it into an electrical signal, and a plurality of photoelectric conversion means that receives the reflected light from the original into the photoelectric conversion means. an imaging optical system for inputting the digital data, an analog-to-digital conversion unit for converting the analog output of the photoelectric conversion unit into digital data, a plurality of line memories for storing the digital data, and a plurality of line memories for storing the output of the line memories. It is equipped with a memory control means for controlling and a sensor control means for driving the photoelectric conversion means, and the plurality of photoelectric conversion means are arranged on one line each other and photoelectrically convert the reflected light of the document one line at a time. At the same time, it photoelectrically converts the light reflected from the original into a line, has an image reading area divided into a plurality of pixels in a direction perpendicular to the line, and manually inputs the output of each pixel sequentially to an analog-digital conversion means. Further, the plurality of photoelectric conversion means each have a portion that receives reflected light from the document in an overlapping manner, and the memory control means controls each effective pixel area for an image read in the overlapping light-receiving portion.

The memory control means includes a comparison means for determining the contents of the line memory, an address generation means for reading the contents of the line memory, an output of the address generation means, and an output of a plurality of photoelectric conversion means. It consists of a means for controlling the connection of one line of read image, which is crimped to read the image on the document surface, reads a reference surface having optically high reflectance for shading correction, and a means for controlling the connection of one line of read image. The optically high-reflectance reference surface has an optically low-reflectance portion for roughly displaying the connecting portion of images read by a plurality of photoelectric conversion means, thereby simplifying the structure. The cost is low, and each divided area of a document image read by a plurality of photoelectric conversion means can be easily connected.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of main parts of an image reading device in an embodiment of the present invention, FIG. 2 is a circuit block diagram of an embodiment,
FIG. 3 is a timing diagram of the main parts of one embodiment, FIG. 4 is a schematic diagram of the main parts of a conventional image reading apparatus, and FIG. 5 is an output signal waveform diagram of the conventional image reading apparatus. 1) 6...CCD-dimensional image sensor, 1)
8... A/D converter, 1) 9... Line memory, 120... Memory control circuit, 130
...Edge detection circuit, 131 ... Address control circuit, 132 ... Output switching circuit, 13
3... Output synthesis circuit, 134... Switch circuit.

Claims (7)

[Claims] (1) A light source that irradiates the original with light, at least two or more photoelectric conversion means that receives reflected light from the original and converts it into an electrical signal, and a connection for inputting the reflected light from the original into the photoelectric conversion means. an image optical system, an analog-to-digital conversion means for converting the analog output of the photoelectric conversion means into digital data, a plurality of line memories for storing digital data, and a memory control means for controlling the output of the line memories. , and sensor control means for driving a photoelectric conversion means. (2) The image reading device according to claim (1), wherein the plurality of photoelectric conversion means are arranged on one line and photoelectrically convert the reflected light of the original one line at a time. (3) The photoelectric conversion means photoelectrically converts the light reflected from the original into a line, has an image reading area divided into a plurality of pixels in a direction perpendicular to the line, and sequentially converts the output of each pixel into an analog-to-digital conversion means. The image reading device according to claim (2), wherein the image reading device inputs the image data. (4) The plurality of photoelectric conversion means have portions that receive reflected light from the original in an overlapping manner, and the memory control means controls each effective pixel area to read images from the portions that receive light overlappingly. An image reading device according to claim (3). (5) The memory control means includes a comparison means for determining the contents of the line memory, an address generation means for reading the contents of the line memory, and counts the output of the address generation means, and calculates the output of the plurality of photoelectric conversion means. The image reading apparatus according to claim 4, further comprising means for controlling the connection of one line of the formed read image. (6) Claim (5) characterized in that in order to read the image on the document surface, a reference surface having optically high reflectance for shading correction is read in advance.
The image reading device described in Section 1. (7) The reference surface having optically high reflectance for shading correction is characterized by having an optically low reflectance portion for approximately displaying the connected portion of the image read by the plurality of photoelectric conversion means. An image reading device according to claim (6).