JPS63260359A - Method and apparatus for reading picture - Google Patents

Abstract

PURPOSE:To obtain a picture signal with high resolution by splitting a light from picture information on an original into two directions by an optical split means having a total reflection section and a total transmission section and using plural line sensors arranged in each direction so as to read the picture information. CONSTITUTION:The light from the picture information between b1 and b2 of the original S is collected by a condenser lens 18 and the image is formed on a CCD 12 through the total transmission section 22a of the optical split member 20. Moreover, the light from the picture information between the parts b2 and b3 is collected by the condenser lens 18 and deflected upward by 90 deg. in the progressing direction by the total reflection section 22b of the optical split member 20 and the image is formed on a CCD 14. Moreover, the light from the picture information between the parts b3 and b4 is collected by the condenser lens 18 and the image is formed on a CCD 16 through the total transmission section 22c of the optical split member 20. In this case, the picture information between the parts b1 and b4 on the main scanning line 21 is converted into an electric signal by plural photoelectric conversion sections arranged in a line shape to the CCDs 12, 14 and 16. Thus, the light from the picture information very efficiently reaches the line sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image reading method and apparatus, and more particularly, the present invention relates to an image reading method and an apparatus, and more particularly, the present invention relates to an image reading method and an apparatus, and more particularly, the present invention relates to an image reading method and an apparatus, and more specifically, the present invention relates to an image reading method and an apparatus, and more specifically, when reading an image, light obtained from an original image is divided into two directions by a light splitting means having a total reflection part and a total transmission part. The present invention relates to an image reading method and apparatus for reading image information using line sensors arranged in each direction.

In recent years, image scanning recording and reproducing systems that electrically process image information carried on manuscripts and create film master plates have been widely used in the fields of printing and plate making for the purpose of streamlining work processes and improving image quality. ing.

This image scanning, recording and reproducing system basically consists of an image reading device and an image reproducing device. That is, in an image reading device, a document that is conveyed in a sub-scan direction in an image reading section is main-scanned by a photoelectric conversion element, and the image information is converted into an electrical signal. Next, the image information photoelectrically converted by the image reading device is subjected to arithmetic processing such as gradation correction and edge enhancement according to plate-making conditions in an image reproduction device, and then the image information is converted into an optical signal such as a laser beam. The recorded information is converted into a photosensitive material and recorded and reproduced on a record carrier made of a photosensitive material such as film. Note that this recording carrier is developed by a predetermined developing device and used as a film original for printing or the like.

Incidentally, when the image reading device main-scans a document and reads its image information, a COD (charge-coupled device) is generally used as a line sensor. Here, the COD has a large number of elements that perform photoelectric conversion arranged in a line at high density, and the number of elements in a normal CCD is about several thousand at most. Therefore, one CCD
If the image information of the document is to be read using this method, there will be a problem in that it will not be possible to completely scan a document having a large width in the main scanning direction, or the resolution of the read image information will be considerably reduced. In this case, manufacturing a dedicated CCD with a large number of elements arranged requires a large manufacturing cost and is not practical.

Therefore, in order to obtain high resolution, multiple CO
D is used to read image information, and a technical idea disclosed in Japanese Patent Application Laid-Open No. 58-202661 has been proposed as a suitable example.

That is, in FIG. 1, light containing image information from a document S illuminated by a linear light source (not shown) enters a half mirror 4 via a condenser lens 2, and is then split into two directions. In this case, a CCD 6 for reading image information between one end a and the center ag of the original S is disposed on one side of the half mirror 4, and a CCD 6 is disposed on the other side of the half mirror 4 in the rear direction. A CCD 8 is disposed to read image information between the central portion at and the other end a of the document S. Therefore, the light reflected by half mirror 4 is
The light transmitted through the half mirror 4 is photoelectrically converted to obtain an image signal by the D6, and the light transmitted through the half mirror 4 is photoelectrically converted by the CCD 8 to obtain an image signal, and these image signals are electrically combined to create an image between a and 31. I'm getting a signal. In addition,
The original S is main-scanned in the direction of arrow A by the CCDs 6 and 8, and is also sub-scanned and conveyed in the direction of arrow B, so that image information on the entire surface thereof is read.

However, in this prior art, the amount of light of image information input to C0D6 and C0D8 is reduced by 50% by the half mirror 4.
It has been pointed out that there is an inconvenience that a clear image cannot be obtained because the light is attenuated below. Therefore, multiple C
Although CD6 and CD8 are used, no effective improvement in resolution can be expected and it is extremely uneconomical. In addition, in order to compensate for the decrease in light intensity caused by the half mirror 4, it is also possible to increase the output of the light source disposed close to the main scanning line of the original S, but in this case, the heat generated from the light source may be This becomes a problem, and various inconveniences occur, such as requiring a large amount of electric power to drive the light source.

The present invention has been made to overcome the above-mentioned disadvantages, and the present invention divides light from image information carried on a document into two directions by a light splitting means having a total reflection part and a total transmission part. The image information is read and synthesized by a plurality of line sensors arranged so that their ends are optically overlapped, and light from the image information is efficiently guided to the line sensor, thereby making the image information highly accurate. An object of the present invention is to provide an image reading method and device that can read images.

To achieve the above object, the present invention reads a portion of the image information along the main scanning line of a document by at least one line sensor, and reads another portion of the image information along the main scanning line by total reflection. At least one mirror that reflects the image information and optically superimposes the image information on the end of the line sensor.
reading by two other line sensors, and then adding a superimposed portion of the image signal obtained from the line sensor and the image signal obtained from the other line sensor to create an image signal along the main scanning line. It is characterized by

The present invention also provides an image reading device that main-scans and reads image information carried on a document using a plurality of line sensors, in which at least one sensor reads a portion of the image information along the main scanning line of the document through a condensing optical system. one line sensor,
at least one other line sensor that reads another part of the image information along the main scanning line via the condensing optical system; It is characterized by comprising image information dividing means for dividing and guiding image information to each sensor.

Next, preferred embodiments of the image reading method according to the present invention in relation to a device for carrying out the method will be listed.
A detailed description will be given below with reference to the accompanying drawings.

In FIGS. 2 and 3, reference numeral 10 indicates the main body of the image reading device according to the present invention. The main body 10 includes CCDs 12.14 and 16 as line sensors that photoelectrically read light containing image information from a document S illuminated by a linear light source (not shown), and CCDs 12.14 and 16 that read light containing image information from a document S illuminated by a linear light source (not shown). It basically consists of a condensing lens 18 that condenses the light into two directions, and a light splitting member 20 serving as an image information splitting means that splits the light into two directions perpendicular to each other.

The CCDs 12 and 16 are arranged on a straight line parallel to the main scanning line 21 of the original S with a predetermined distance between them.

Further, the condenser lens 18 is disposed at a predetermined position between the CGDIs 2 and 16 and the original S to focus light from image information along the main scanning line 21 of the original S onto the CCDs 12 and 16.

On the other hand, the light splitting member 20 includes the condenser lens 18 and the CCD 12 .
16, and is arranged at an inclination angle of 45° with respect to the scanning surface of the document S. In this case, the light splitting member 20 is formed at the center of the light splitting member 20, and includes a fully transparent part 22a that guides light from image information between main scanning lines 21 of the original S to the CCD 12, and a bt , b, a total reflection section 22b that deflects the traveling direction of light from image information between 90', b, ,
It is composed of a fully transparent section 22c that guides light from image information between b4 to the CCD 16.

In the traveling direction of the light reflected by the total reflection section 22b of the light splitting member 20, a CCD 14 is disposed at a position optically conjugate with the CCDs 12 and 16.

In this case, light from image information between the edges of the original S is incident on the CCD 14. Note that both ends of the CCD 14 and each end of the CCDs 12 and 16 are arranged so that they optically overlap each other, as shown in FIG.
Set positions 4 and 16 in advance.

The image reading device according to this embodiment is basically configured as described above.Next, an image reading method using this device and its effects will be explained.

Therefore, in the manuscript S...b! The light from the image information in between is focused by the condensing lens 1, and the light splitting member 20
The light passes through the entire transparent part 22a and is imaged on the CCDCD.

Also, b! , b3, the light from the image information is passed through the condenser lens 1.
8, the total reflection part 2 of the light splitting member 20
2b, its traveling direction is deflected upward by 90°, and an image is formed on the CCD 14. Further, the light from the image information between b and b4 is condensed by the condenser lens 18, passes through the total transmission part 22c of the light splitting member 20, and forms an image on the CCD 16. In this case, bt carried on the main scanning line 21
, b4 is converted into an electrical signal by a plurality of photoelectric conversion sections arranged in a line in the CCDs 12, 14 and 16.

Here, for example, let us assume that the number of photoelectric conversion sections constituting each of the CCDs 12, 14 and 16 is 100, and the image signals photoelectrically converted by each photoelectric conversion section are A, thru A, 1).

, B1 to BIOo and C, to C1°.

Then, the CCD 12. whose ends overlap each other.
The relationship between the arrangement of 14 and 16 and the image signal is as shown in FIG. 4a. In this case, when the reflected light from a white original as the original S is photoelectrically converted by the CCDs 12, 14 and 16, image signals obtained from each photoelectric converter are as shown in FIGS. 5a to 5C. Here, CCD12.14
In the overlamp portion II and the overlap portion 12 of the CCD 14.16, an image signal resulting from the transmitted light of the total transmission section 22a and the reflected light of the total reflection section 22b near the boundary of the light splitting member 20 appears. Therefore, by adding these image signals, the image signal shown in FIG. 5d is obtained.

Therefore, to explain the case of FIG. 4a, the image information between bl and b4 in the original S is the image signal obtained from the photoelectric conversion section of each CCD 12, 14 and 16, as shown in FIG. AI to A911, B3 to 8911 and C1 to Cl0II and the overlap part l1
It is formed by the signal obtained by adding the two image signals.

The image signal shown in FIG. 4 can be obtained by the circuit configuration shown in FIG. That is, this circuit is C
An analog switch 26 selectively supplies image signals photoelectrically converted by CDs 12, 14 and 16 to an adder 24, a counter 28 that controls the operation of the analog switch 26, and converts the output signal of the adder 24 into a digital signal. and an A/D converter 30 for conversion.

Therefore, the analog switch 26 is operated by the switching signal from the counter 28 to connect the CCD 12 and the adder 24. In this case, the adder 24 outputs the image signals A1 to A911 obtained from each photoelectric conversion section of the CCD 12 to the A/D converter 30 based on the clock signal supplied to the counter 28. A digital image signal is formed.

Next, when the counter 28 counts a predetermined number of the clock signals, it outputs a switching signal to the analog switch 26 based on a control signal from a control section (not shown). The analog switch 26 supplies the image signal from the CCD 12 and the image signal from the CCD 14 to the adder 24 in response to the switching signal. At this time, the adder 24 receives the image signal AH1A1°. and B,,B.

and outputs the result to the A/D converter 30, which converts the added image signal into a digital image signal.

Furthermore, when the counter 28 counts the clock signal corresponding to the overlap portion 1 between the CCD 12 and the CCD 14, it again outputs a switching signal to the analog switch 26 based on a control signal from a control section (not shown). At this time, the analog switch 26 receives the image signal B from the CCD 14.
, to Bll are output to the adder 24. Therefore, the adder 24 outputs the image signals B to 89m from the CCD 14 to the A/D converter 30, and this image signal is converted into a digital image signal.

Similarly, the analog switch 26 is driven based on the switching signal from the counter 28, and the image signal B9! is output from the CCDs 14 and 16! , BIOo, C, ,C, addition processing and digital conversion, and image signals C1 to C8
゜. A digital conversion is performed to form the image signal shown in FIG.

On the other hand, in the above-mentioned synthesis circuit, CCD12.14 and 1
Although the image signal obtained in step 6 is subjected to addition processing as an analog signal, it is also possible to perform addition processing as a digital signal, as shown in FIG.

That is, the image signal photoelectrically converted by the CCD 12 is supplied to the A/D converter 32 via an analog switch 31 controlled by a switching signal, and is converted into a digital signal. Then, the digital signals are sent to the X side by a selection signal via the selector 34, except for the image signal of the overlap part I1, and the image signal of the overlap part 11 is sent to the Y side and stored in the memory 36.

Next, when all the signals from the CCD 12 are read out, the analog switch 31 is controlled by the switching signal, and the CCD 14 and the A/D converter 32 are connected. Then, CCD14
The image signal photoelectrically converted is supplied to an adder 38 via an A/D converter 32 and a selector 34. In this case, the overlap part between CCD14 and CCD12! , is read out from the CCD 14, the memory 36
The image signals of the overlap portion l of the CCD 12 stored in the adder 38 are added together. Similarly,
The overlap portion molecule it of the CCD 14 and CCD 16 is also processed to generate an image signal.

In this way, the image information between bl and b4 of the original S is sequentially converted into digital signals to form an image signal. Note that the original S is main-scanned in the direction of arrow A by the CCDs 12, 14 and 16, and is conveyed in the sub-scanning direction in the direction of arrow B by a conveyance mechanism (not shown), thereby forming an image signal for the entire surface thereof.

As described above, according to the present invention, light from image information carried on a document is divided into two directions by a light splitting means having a total reflection part and a total transmission part, and a plurality of line sensors arranged in each direction are used. The image information is read by Therefore, light from image information traveling towards each line sensor is not absorbed in its optical path and reaches the line sensor very efficiently. As a result, an image signal with high resolution can be obtained. Further, since the image signal can be synthesized by simply adding the output signals from each line sensor, an advantage is obtained that the configuration is extremely simple.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
For example, various improvements and design changes can be made without departing from the gist of the present invention, such as eliminating the total transmission part from the light division means and configuring the light division means with a reflecting mirror having only a total reflection part. Of course.

[Brief explanation of drawings]

1 is an explanatory diagram of an image reading device according to the prior art; FIG. 2 is a perspective explanatory diagram of the configuration of an image reading device according to the present invention; FIG. 3 is a plan explanatory diagram of the image reading device according to the present invention; Figures a and b are explanatory diagrams of the relationship between the position of the line sensor and the image signal obtained from each line sensor in the image reading device according to the present invention, and an explanatory diagram of the combined image signal, and Figures 5 a to d are diagrams of the present invention FIG. 6 is a circuit block diagram configuring the image reading device according to the present invention; FIG. 7 is a circuit diagram of another embodiment of the image reading device according to the present invention. It is a block diagram. 10... Main body 12.14.16...
・CCD18...Condensing lens 20...Light splitting member 22a...Total transmission part 22b...
Total reflection part 22c...Total transmission part 30...A
/D converter S...manuscript

Claims (4)

[Claims] (1) A part of the image information along the main scanning line of the document is read by at least one line sensor, and another part of the image information along the main scanning line is reflected by a total reflection mirror, and the image information is transferred to the is read by at least one other line sensor optically superimposed on the end of the line sensor, and then the overlapping portion of the image signal obtained from the line sensor and the image signal obtained from the other line sensor is added. An image reading method characterized by creating an image signal along the main scanning line. (2) In an image reading device that main-scans and reads image information carried on a document using a plurality of line sensors, at least one line reads a portion of the image information along the main scanning line of the document via a condensing optical system. a sensor, at least one other line sensor that reads another part of the image information along the main scanning line via the condensing optical system, and a total reflection section that reads the image information along the line sensor and the An image reading device comprising image information dividing means for dividing and guiding image information to other line sensors. (3) In the device according to claim 2, the image information dividing means includes a total reflection section that guides a part of the image information to the line sensor, and a total transmission section that guides the other part of the image information to another line sensor. An image reading device comprising: (4) An image reading device according to claim 2 or 3, wherein the end portions of the line sensor and the other line sensor are optically overlapped.