JPH0865524A - Picture reader - Google Patents

Abstract

PURPOSE: To suppress blurring at the time of scanning, to hold fine picture quality and to prevent noise by thresholding picture data read out of an original while feeding it at an equal speed and successively storing the binary data in a memory. CONSTITUTION: A thresholding processing circuit 4 converts picture data read out by a CCD sensor 3 while feeding an original G at an equal speed and successively stores the binary data in a buffer memory 5. The length of the original G is found out by the use of an original start end detecting sensor S1 and an original final end sensor S2 or based on the ON time of a paper sensor and the paper feeding speed. When the sub-scanning direction length of picture data stored in a buffer memory 5 is longer than the practical size of the original G, an image correcting means 6 executes thinning processing, and when the length is shorter, executes interpolating processing. Thereby the picture data are corrected to a memory image approximate to the length size of the original image G and the corrected picture data are encoded in a encoding circuit 7 and outputted to a picture memory 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus applied to, for example, a facsimile machine or a scanner.

[0002]

2. Description of the Related Art In a facsimile, a document to be transmitted on the transmission side is optically read by a scanner for each scanning line and transmitted, and when one scanning is completed, the transmission document is moved by one scanning line and is moved to the next scanning line. The image signal of is read and transmitted. And
By repeating this operation, the originals are sequentially transmitted.

On the other hand, the receiving side receives the image signal sent from the transmitting side as described above, reproduces and records it, and prints it out. In such a facsimile, since the band compression technique is used, the feed speed of each scanning line differs depending on the encoding processing speed. In such a conventional facsimile,
After scanning one line or several lines for scanning, binarizing the image data, accumulating it in the buffer memory, encoding the image signal, and after the encoding process is completed,
A commonly used stepping motor is driven to read the next line.

Therefore, when the encoding process takes a long time, the stepping motor is made to stand by in a stationary state, and the stepping motor cannot be driven until the encoding process is completed. Therefore, if the encoding process takes a long time, the reading scan is stopped, the image signal feed speed becomes unequal, and the transmission original and the recording paper also become unequal. Further, the stepping motor emits noise because it intermittently feeds paper every scanning.
It consumes a lot of power.

As described above, in the conventional facsimile, since the stepping motor is step-operated to perform the reading scanning, there is a discrete change (step operation) such as start-up and braking, and vibration is generated during the reading scanning to cause a blur in reading the original. Occurs, and if, for example, the pixels are clogged, skipped reading may occur and the read image quality may deteriorate.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, in which blurring does not occur during reading and scanning, and therefore a good reading image quality is maintained, and further, vibration does not occur, and therefore a large amount is obtained. An object is to provide an image reading device that does not generate noise.

[0007]

The present invention proposed to achieve the above object has the following structural features. That is, the image reading device described in claim 1 is
While sending the original at a constant speed, the scanned image data
A binarization processing circuit for performing a binarization process, a buffer memory for sequentially accumulating the binarized image data, and the image data accumulated in the buffer memory is corrected to the number of lines according to the size of the original paper. The image correction unit includes an image correction unit and an encoding circuit that encodes the image data corrected by the image correction unit.

Here, unlike the conventional line buffer, the buffer memory is required to have a capacity that does not affect the reading scan even if the encoding process takes time. An image reading apparatus according to a second aspect is the image reading apparatus according to the first aspect, wherein the image correction unit performs thinning processing when the image data read from the original is larger than the size of the original paper. On the other hand, when the size is smaller than the size of the recording paper, the interpolation processing is performed.

According to a third aspect of the present invention, in the image reading apparatus according to the first or second aspect, the size of the original document scanned for image data and scanned is such that the original end and the end of the original document sensor. It has a configuration defined by being read by.

[0010]

According to the present invention, the following actions are exhibited.
That is, in the image reading device according to the first aspect, the image data read is binarized by the binarization processing circuit while the original is fed at a constant speed, and the binarized image data is buffered. Accumulate in memory one by one.

Then, the image data stored in the buffer memory is corrected by the image correction means to the number of lines according to the size of the original paper, and the corrected image data is sequentially encoded by the encoding circuit. For this reason, since the reading of the original image and the encoding process can be performed separately, it is not necessary to wait for the reading of the original document until the end of the encoding process even if the encoding process takes time.

In the image reading apparatus according to the second aspect,
When the image data read from the original is larger than the size of the original paper, the thinning process is performed, but when the image data is smaller than the size of the recording paper, the image correction unit performs the interpolation process. Therefore, the number of lines can be easily corrected. In the image reading apparatus according to the third aspect of the present invention, the size of the original document scanned by the image data is defined by reading the start end and the end of the original by the original sensor, so that the number of lines of the original is corrected more accurately. can do.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image reading apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a hardware configuration of an embodiment of an image reading apparatus according to the present invention. In this embodiment, an image reading apparatus applied to a facsimile apparatus will be described.

The image reading apparatus of the present invention receives the reflected light from the light source 2 for projecting light on the document sheet G arranged on the front side of the back plate 1 and the image of the document G by receiving the reflected light from the document G. CCD sensor 3 for reading and scanning line by line,
A document that is defined by scanning the beginning and end of document G (starting edge)
A sensor S1 and a document (end) sensor S2 are provided.

The CCD sensor 3 is followed by a CCD.
A binarization processing circuit 4 for converting an analog image signal (image data) output from the sensor 3 into a binarized image signal (image data), and sequentially accumulating the binarized image data. A relatively large capacity buffer memory 5
An image correction unit 6 that corrects the image data accumulated in the buffer memory 5 to the number of lines according to the size of the document sheet G, and an encoding circuit that encodes the image data corrected by the image correction unit 6. 7 and an image memory 8 for storing the image compression data encoded by the encoding circuit 7 and the like.

In this image reading apparatus, the original paper G is fed at a constant speed by using a small motor as a power source. This feed speed is based on the original scanning mode (Super Fine,
Fine and normal), it becomes slower as the line density increases. That is, it becomes slower in the order of normal, fine, and super fine. It is not necessary to use a stepping motor as a small motor as in the conventional case, and a general small motor can be used as a power source.

The original paper G is read and scanned by the CCD sensor 3, and the feed length dimension d of the original paper G in the sub-scanning direction is
Original (starting) sensor S1 and original (ending) sensor S2
Stipulated in. It should be noted that the sensor may be one that detects the presence or absence of the original paper G, and the length of the original paper G may be obtained from the time when this sensor is on (it turns on when there is paper) and the paper feed speed. .

The analog image data output from the CCD sensor 3 is converted into binarized image data by the binarization processing circuit 4, and the binarized image data is sequentially stored in the buffer memory 5. Accumulated. Here, the buffer memory 5 has a relatively large capacity, and unlike the conventional line buffer memory, has a capacity that does not affect the reading scan even if the encoding process takes time. Is adopted.

The image correction means 6 uses the buffer memory 5
The length dimension d in the sub-scanning direction of the image data stored in
If it is longer than the actual length dimension d of the original sheet G, the number of lines is thinned out, and if it is shorter than the actual length dimension d of the original sheet G, the line number is interpolated and stored in the buffer memory 5. Correct the length dimension (number of lines) of the image data. FIG. 2 is an explanatory diagram showing a specific example in which the image data of the original paper G is processed.

When the length dimension (the number of lines) of the memory image in the buffer memory 5 in the sub-scanning direction is D, D> d
In the case of, the memory image is thinned out to d / D and printed out or transmitted. If D <d, the memory image is interpolated to d / D and is printed out or transmitted.

However, in reality, when D <d, the image quality deteriorates due to the lack of the information amount of the read image data.
Even in the case of D >> d, the amount of thinning out the information amount of the image data is too large, and the image quality deteriorates. Therefore, d <D <2
It is preferable to adjust to about d, and it is most preferable to adjust the number of lines to about D = 1.1d.

When D = 1.1, as shown in FIG.
If the length dimension of the original document G in the sub-scanning direction is, for example, 10 cm, the length dimension of the memory image in the buffer memory 5 is 11 cm. And this image memory is
The image correction unit 6 thins out the number of lines on October 11.
That is, one line is thinned out every 11 lines. Then, the image is corrected by the image correction means 6 into a memory image having the same length as the original document G, and is output to the encoding circuit 7.

The output image data is encoded in the encoding circuit 7 with a run length of MR or MH. Then, it is output to the image memory 8 and stored in the image memory 8. In the above embodiments, the image reading device is applied to a facsimile device, but the present invention is not limited to this and can be applied to a scanner such as a copying machine or a general scanner.

The present invention is not limited to the above-described embodiments, and design changes can be made without departing from the gist of the present invention.

[0025]

Since the present invention is configured as described above, it has the following effects. According to the first aspect, while the document is being sent at a constant speed, the read image data is binarized by the binarization processing circuit, the image data is accumulated in the buffer memory, and the accumulated image data is converted into an image. The correction means corrects the number of lines according to the size of the original paper, and the corrected image data is encoded and output by the encoding circuit. Therefore, the reading of the original is stopped until the time-consuming encoding process is completed. You don't have to. Therefore, since blurring does not occur during reading and scanning, good reading image quality is maintained, vibrations are reduced, and large noise is not generated.

According to the second aspect, when the image data read from the original is larger than the size of the original paper, the thinning process is performed, and when the image data is smaller than the size of the recording paper, the interpolation process is performed by the image correction means. Since it is performed in step 1, the image can be easily corrected. According to the third aspect of the invention, the size of the document sheet scanned and read with the image data is defined by reading the start and end of the document with the document sensor, so that the number of lines of the image can be corrected more accurately.

[Brief description of drawings]

FIG. 1 is a block diagram showing a hardware configuration of an embodiment of a document reading apparatus according to the present invention.

FIG. 2 is an explanatory diagram showing a specific example in which image data of a document sheet is processed in an example of a document reading apparatus according to the present invention.

[Explanation of symbols]

 4 Binarization processing circuit 5 Buffer memory 6 Image correction means 7 Encoding circuit G Original paper S1 Original sensor S2 Original sensor

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Claims (3)

[Claims] 1. A binarization processing circuit for binarizing read image data while feeding an original at a constant speed, a buffer memory for sequentially accumulating the binarized image data, and this buffer memory. An image reading apparatus including an image correction unit that corrects the image data accumulated in the image data into a number of lines according to the size of a document sheet, and an encoding circuit that encodes the image data corrected by the image correction unit. 2. The image correction means performs thinning processing when the image data read from the original is larger than the size of the original paper, and interpolation processing when the image data is smaller than the size of the recording paper. The image reading device according to claim 1. 3. The image reading apparatus according to claim 1, wherein the size of the original document scanned by reading the image data is defined by reading the start and end of the original with an original sensor.