JP2950962B2 - Image reading apparatus and image reading method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image reading apparatus and an image reading method,
In particular, the present invention relates to an image reading apparatus and an image reading method for continuously transporting a sheet-shaped document and reading both sides of the document image at a high speed by an image sensor provided on a transport path.

2. Description of the Related Art Conventionally, in order to handle a double-sided original in an image reading apparatus of this type, a single original is transported twice, the front side is first read, and then the original is turned over and the rear side is read, or A transport path having a length twice or more the length of the document to be read is provided, and a document transport reading mechanism is used, such as reading the front surface in the first half of the transport path and then reading the back surface in the second half of the transport path.

[Problems to be Solved by the Invention] However, in the above-described conventional example, although it is possible to read a double-sided image, in the case of the former two-time transport type, the original is It is necessary to provide a mechanism for manually passing the document twice, or a mechanism for automatically passing the document twice through the reading section provided on the transport path. Providing a mechanism that takes a long time and automatically feeds the paper twice automatically complicates the configuration of the document conveyance path, increases the manufacturing cost of the machine, and also causes a paper jam of the document.
The danger of the increase.

On the other hand, in the case of the latter one-time transport type, a transport path having a length that is at least twice as long as that of a normal paper is required. It has a problem to be solved.

SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide an image reading apparatus and an image reading method that have a function of reading the front and back of a double-sided document, are compact, inexpensive, and are capable of high-speed reading.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a conveying means for conveying a document, and continuous scanning of the front and back sides of a document image continuously conveyed by the conveying means. Double-sided image reading means for reading in a line, image storage means for temporarily storing two-sided images on the front and back read by the two-sided reading means, and image for reading double-sided images temporarily stored and stored in the image storage means Reading means, selecting means for selecting whether to handle the front and back of the double-sided image read by the image reading means collectively, or separating and handling the front and back, and selecting the front and back images collectively or separated by the selecting means. Output means for selectively outputting to the next stage.

The method of the present invention further includes a reading step of reading an image on the front surface and an image on the back surface of the document, a connecting step of connecting the read image on the front surface and the image on the back surface line by line, and forming a new line. A compression step of compressing the connected image information, a storage step of temporarily storing the compressed image information in a buffer memory, an expansion step of expanding the image information stored in the buffer memory, and an expanded image A separation / selection step of separating and selecting the image information of the front side or the back side from the information, a second compression step of compressing the image information separated and selected, and the image information compressed in the second compression step. And outputting at a stage.

[Operation] In the present invention, the front and back sides of a two-sided original are read simultaneously at substantially the same physical position, the front and back sides of the original image are treated as one continuous scanning line, and then subjected to image processing and temporarily accumulated and stored. Re-read and separate the front and back of the two-sided image
Since the image is reconstructed and the images on the front and back sides of the original are selected and output to the next stage, when reading the front and back sides of the double-sided original, high-speed processing can be performed at low cost at a compact size.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

First Embodiment FIG. 1 shows a basic circuit configuration of a first embodiment of the present invention. In FIG. 1, reference numerals 1a and 1b denote CCD image sensors that simultaneously read the front and back surfaces of a conveyed document, respectively. 2 is a CCD image sensor 1a, 1b
This is a synthesizing circuit composed of analog switches for synthesizing analog pixel data from each other and combining them into one signal. 3
Converts the analog pixel data from the synthesis circuit 2 into digital multi-valued pixel data by A / D (analog / digital) conversion and further performs the necessary digital image processing to improve the image quality. This is an image binarization circuit that performs binarization by a comparator.

An input switching circuit 4 selects one of the two binary image data. Reference numeral 12 denotes a front and back image management circuit for selecting whether to input the output signal of the input switching circuit 4 and output the image to the next stage as a front and back batch or separate and output one of the front and back sides. An image data compression circuit 5 encodes the binary image data from the front and back image management circuit 12 to compress the image. 6
Is an image data decompression circuit for decoding the coded image data and restoring it to binary image data. Reference numeral 7 denotes an image buffer RAM for temporarily storing the encoded image data. Reference numeral 8 denotes a transfer control circuit that controls transfer with a SCSI (small computer system interface) bus, and 9 denotes a SCSI bus that finally outputs image data. Reference numeral 10 denotes an image data transfer control circuit (DMA transfer control circuit) for controlling image data transfer between devices.

FIG. 2 shows the details of the reading section of the basic configuration of the first embodiment of the present invention. The two-sided original 25 conveyed between the conveyance guides 22a and 22b by each of the two pairs of conveyance rollers 20a, 20b, 20c and 20d is read by a reading unit provided at substantially the same physical position. The image (reflected light) on the surface of the original 25 is projected and formed on the above-described front-surface reading CCD image sensor 1a via an optical path passing through a reading glass 21a, a total reflection plate 23a, and an imaging lens 24a. The back side image (reflected light) of the CCD image sensor 1b for back side reading described above passes through an optical path passing through the reading glass 21b, the total reflection plate 23b, and the imaging lens 24b.
Projected and imaged on the top.

Here, returning to FIG. 1, the operation of the apparatus of this embodiment will be described. The analog pixel data read by the two CCD image sensors 1a and 1b is used for front surface reading in the first half on one scan line.
The output timing is controlled by a CCD transfer drive circuit (not shown) so that the data from the CCD image sensor 1a is output, and the data from the back side reading CCD image sensor 1b is output in the latter half. The analog pixel data output from the two CCD image sensors 1a and 1b are synthesized by the analog switch 2 as shown in FIG. 3, and the first half of one scanning line is composed of front side image data and the second half is composed of back side image data. One signal line.

Next, the analog switch 2 is operated by the image binarization circuit 3.
A / D conversion is performed on the analog pixel data synthesized in step (1) to convert it into digital multi-valued pixel data. Further, digital image processing necessary for improving image quality is performed, and then binarization processing is performed. Subsequently, the pixel data that has been subjected to the binarization processing is output to the image binarization circuit 3.
The front and back image management circuit 12 further switched to the front and back batch output state via the input switching circuit 4 switched to the
After that, the image data is encoded by the image data compression circuit 5 in a sequential process, input to the image buffer RAM 7 under the control of the image data transfer control circuit 10, and temporarily stored.

Next, after switching the input line of the input switching circuit 4 to the image data decompression circuit 6 side, the compressed image data temporarily stored in the image buffer RAM 7 is read out by the image data transfer control circuit 10, The data is sent to the data decompression circuit 6 and is sequentially decoded. Subsequently, the decoded signal passes through an input switching circuit 4, and this time, a front and back image management circuit
According to 12, only one of the first half (ie, the front side image data) or the second half (ie, the back side image data) in one scan line is selected, and the image data compression circuit 5 performs re-encoding processing. The processing result is transferred to the SCSI bus transfer control circuit 8 under the control of the image data transfer control circuit 10,
The data is output to the SCSI bus 9 under the control of the control circuit 8.

With the above operation, the front and back batch compressed images temporarily stored in the image data buffer RAM 7 are temporarily decoded, and then only one of the front and back surfaces is selected and re-encoded on a page basis to the SCSI bus 9. As shown in FIG. 2, the image reading unit is configured to be simple (simple) and compact (compact), and selectively (or continuously) the front image and the back image. An image reading device capable of outputting the image can be realized.

A buffer RAM 7 for temporarily storing front and back batch images
Since the image data stored in the memory is compressed (encoded) data, the required memory capacity can be significantly reduced, and the cost of the apparatus can be reduced.

Second Embodiment FIG. 4 shows a circuit configuration of a second embodiment of the present invention. In this embodiment, two buffer RAMs 7a and 7b for temporarily storing compressed image data are provided, and an external storage device 11 is provided on the SCSI bus 9 to enable continuous reading of double-sided images. , Thereby speeding up,
By temporarily storing a plurality of double-sided batch images in the external storage device 9, batch processing of a plurality of images is also possible. The details will be described below.

In FIG. 4, the same reference numerals as in FIG.
It is a block component having the same function. 7a and 7b are first image data buffer RAMs each having the same function.
Reference numeral 11 denotes a buffer RAM for second image data, and 11 denotes a magnetic disk device for temporarily storing image data connected to the SCSI bus 9.

First, in the same processing procedure as described in the first embodiment, 2
The image data of the first document read by the two CCD image sensors 1a and 1b is temporarily stored in the first image data buffer RAM 7a, and then the image data of the second document is stored in the second image data.
It is temporarily stored in the image data buffer RAM 7b. At the same time, in parallel with this work, the image data transfer control circuit 10
Reads the previously stored image data from the first image data buffer RAM 7a and records the read data on the magnetic disk device 11 via the SCSI bus 9 under the control of the SCSI bus transfer control circuit 8.

By repeating the processing operations described above and operating the first and second image data buffer RAMs 7a and 7b in a double buffer configuration, the continuously transported double-sided originals can be sequentially transferred without stopping the originals. The data is recorded on the magnetic disk device 11.

Next, after recording the required number of documents within the capacity of the magnetic disk drive 11, this time, the first page of a series of documents temporarily recorded earlier on the magnetic disk drive 11 is read out and the first page is read.
The image data is re-stored in the image data buffer RAM 7a or the second image data buffer RAM 7b.

The double-sided batch compressed image data re-stored in the first or second image data buffer RAMs 7a and 7b is processed by the image data decompression circuit 6 in the same processing procedure as described in the first embodiment.
The image data is separated (decompressed) by the front and back image management circuit 12, separated into front and back images, and then re-encoded (compressed) by the image data compression circuit 5 and output to the other device 11 on the SCSI bus 9. .
Further, by sequentially repeating the processing procedure described above, the front and back sides of a series of originals read earlier are separated, and the re-encoded image data is continuously transmitted to another device 11 on the SCSI bus 9.
Can be output.

Therefore, in the present embodiment, the reading speed of the document is improved as compared with the first embodiment, and a plurality of documents are collectively temporarily recorded in the buffer RAM, and then the front and back sides are collectively separated and output. Is possible.

In the above series of descriptions of the embodiments of the present invention,
The image data after the front and back separation is encoded (compressed) again
Although the example of outputting to the external device 11 on the SCSI bus 9 has been described, it is of course possible to output to the external device 11 as raw binary image data without re-encoding (compression). In such a case, it is also possible to directly output the data in a state of being encoded (compressed) on the front and back to the external device 11 as it is.

[Effects of the Invention] As described above, according to the present invention, since the front and back surfaces of a double-sided document are simultaneously read and handled as one scanning line, and the front and back surfaces are finally separated and output,
The following effects can be obtained.

Since it is possible to simultaneously read two-sided images at almost the same position, the two-sided image reading device can be configured simply and compactly.

Since the front and back sides of the double-sided image can be handled as one scanning line, only a single electric circuit is required for image processing and the like, so that compactness and cost reduction and high-speed reading processing can be obtained.

Finally, since the front and back images are separated and the front image or the back image is selectively output, an image output in the same image format as another conventional image processing apparatus can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of an image reading apparatus according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view showing details of an image reading section of the embodiment of the present invention, and FIG. FIG. 4 is a block diagram showing a circuit configuration of an image reading apparatus according to a second embodiment of the present invention. 1a: Front side CCD image sensor, 1b: Backside CCD image sensor, 2: Analog switch, 5: Image data compression circuit, 6: Image data expansion circuit, 7: Image Data buffer RAM, 7a: first image data buffer RAM, 7b: second image data buffer RAM, 11: magnetic disk drive, 20a, 20b, 20c, 20d: transport rollers, 21a, 21b ... … Reading glass, 22a, 22b… Transport guide, 23a, 23b… Total reflection plate, 24a, 24b …… Imaging lens, 25 …… Document.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) G06K 9/00-9/82 G06T 1/00 G06T 7/00

Claims (2)

(57) [Claims] And a double-sided image reading means for reading the front and back surfaces of a document image continuously conveyed by the conveying means into one scanning line. Image storage means for temporarily storing read front and back double-sided images; image reading means for reading double-sided images temporarily stored and stored in the image storage means; double-sided images read by the image reading means Selection means for selecting whether to handle the front and back of the front and back together or separately for front and back, and output means for selectively outputting the front and back images separated or front and back by the selection means to the next stage. An image reading apparatus characterized by the above-mentioned. A reading step of reading an image on the front side and an image on the back side of the original; a connecting step of connecting the read image on the front side and the image on the back side line by line to form a new line; A compression step of compressing the image information; a storage step of temporarily storing the compressed image information in a buffer memory; an expansion step of expanding the image information stored in the buffer memory; A separating and selecting step of separating and selecting the image information of the image or the back side, a second compressing step of compressing the separated and selected image information, and outputting the image information compressed in the second compressing step in the next stage An image reading method, comprising: