JP2000216960A - Scanner device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain interpolation processing in a real time. SOLUTION: A digital processing circuit 16 decides whether or not interpolation processing or thinning-out processing should be conducted on an image signal M2, based on a drive timing signal DC and a speed signal VC. At operation of the interpolation processing, the value of a weighting code C corresponding to the image signal M2 is increased, and at operation of the thinning-out processing, the value of the weighting code C is decreased. Then, the image signal M3 is compressed, in response to the weighting code C by a compression processing circuit 18, and a compressed image signal M4 is recorded to a recording part 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanner device for scanning an original document to obtain an image signal.

[0002]

2. Description of the Related Art In a hand scanner for reading an original document by manual scanning, there is a problem in matching the speed of manual movement with the driving cycle of the line sensor, that is, synchronization between sub-scanning and main scanning. For example, if the moving speed in the sub-scanning direction is too fast than a predetermined speed, the imaging interval in the sub-scanning direction is widened. Therefore, when an image signal obtained at that time is reproduced, the subject document shrinks in the sub-scanning direction. Will be displayed. In order to prevent such distortion of the reproduced image, for example, in Japanese Patent Application Laid-Open No. 10-107972, when the moving speed exceeds a predetermined speed, the image signal is line-interpolated to expand the image in the sub-scanning direction. It has been proposed.

FIG. 7 is a block diagram showing the configuration of a conventional hand scanner, and FIG. 8 is a timing chart for explaining its operation. This figure shows a case where digital signal processing is used.

The hand scanner device includes a line sensor 1,
It comprises a drive circuit 2, a speed detection circuit 3, an analog signal processing circuit 4, an A / D conversion circuit 5, a digital signal processing circuit 6, a memory 7, and a recording unit 8. Line sensor 1
A plurality of light receiving pixels arranged at regular intervals and a shift register for transferring and outputting photoelectric conversion charges accumulated in each light receiving pixel; the arrangement direction of the light receiving pixels is a main scanning direction; Attached so that it can move in the direction. The drive circuit 2 generates a transfer clock φh that causes a drive pulse to rise every fixed period T, and this transfer clock φh
Is supplied to the line sensor 1 to transfer and output information charges accumulated in each light receiving pixel of the line sensor 1 via the shift register. As a result, an image signal M0 that is continuous for each row is output from the output unit of the line sensor 1. Further, the drive circuit 2 outputs a drive timing signal DC with which a timing pulse rises in synchronization with the rise of the drive pulse together with the drive clock φh. The speed detecting circuit 3 detects the moving speed of the line sensor 1 with respect to the document, and outputs a speed signal VC whose period is changed according to the detected speed. For example, the speed detection circuit 3
It includes a rotary encoder that rotates with the movement of the line sensor 1, and is configured to raise the speed signal VC every time the line sensor 1 moves a certain distance.

The analog processing circuit 4 samples and holds the image signal M0 input from the line sensor 1,
Processing such as gain adjustment is performed to generate an image signal M1 according to a predetermined format. The A / D conversion circuit 5 samples and holds the image signal M1 input from the analog processing circuit 4 at a timing according to the output operation of the line sensor 1, and digitizes each sampling value to generate an image signal M2. Thus, an image signal M2 representing the light receiving level of each light receiving pixel of the line sensor 1 can be obtained.

The digital processing circuit 6 performs various processes such as contour correction on the image signal M2 to generate an image signal M3. The memory circuit 7 is connected to the digital processing circuit 6 and temporarily stores data required in the processing of the digital processing circuit 6. In the digital processing circuit 6, an interpolation process or a thinning process is performed on the image signal M <b> 2 in units of one line in response to the drive timing signal DC input from the drive circuit 2 and the speed signal VC input from the speed detection circuit 3. Will be applied. That is, as shown in FIG. 8, the moving speed of the line sensor 1 increases, and the speed signal V
When the period L of C (f) becomes shorter than the imaging period T, the rising of the speed signal VC appears twice during the imaging period T at a specific timing. In this case, since two lines of the subject document are represented by one line, the interpolation processing for one line is performed by repeatedly outputting the same data. Conversely, when the moving speed of the line sensor 1 decreases, the period L of the speed signal VC (s) becomes equal to the imaging period T.
If it becomes longer, the rise of the speed signal VC does not appear during the imaging cycle T at a specific timing. In this case, since the subject document for one line is represented by two lines, the thinning process for one line is performed so as to discard the data for one line. Note that the digital signal processing circuit 6 maintains the cycle in which the speed signal VC is substantially equal to the cycle T of the imaging timing signal DC, and the rising edge of the speed signal VC appears once in each imaging period.
Neither interpolation nor thinning is performed.

The recording section 8 is composed of a rewritable recording medium such as a semiconductor memory or a magnetic disk having a capacity capable of recording an image signal corresponding to at least one page of a subject original, and an image input from the digital processing circuit 6. The signal M3 is sequentially captured and recorded. The image signal M3 recorded in the recording section 8 is transferred to a device such as a personal computer or a facsimile in units of one page.

In the above-described hand scanner, even if the moving speed of the line sensor 1, ie, the speed of the sub-scanning, is out of the proper range, the digital processing circuit 6 performs the interpolating process or the thinning-out process for each scanning line. Is performed to prevent distortion of the reproduced image.

[0009]

Since the line sensor 1 operates continuously while moving in the sub-scanning direction with respect to the original document, the analog processing circuit 4 and the A / D conversion circuit 5 perform real-time image processing. The process for signals M0 and M1 is repeated. While such a process is repeated, the digital processing circuit 6 must also repeat the process for the image signal M2 in real time. Therefore, when performing the interpolation process on the image signal M2, the image signal M2 is equivalent to the number of interpolation rows. Need to be delayed. Therefore,
When the interpolation processing continues, the capacity of the memory 7 connected to the digital processing circuit 16 may be insufficient, and the interpolation processing cannot be performed.

Accordingly, an object of the present invention is to enable continuous interpolation processing without using a large-capacity memory.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and is characterized in that the object is moved relatively in the sub-scanning direction with respect to the subject document, and A sensor unit for imaging a document in main scanning line units,
A speed detection unit that detects a relative speed of the sensor unit with respect to the subject document, and a drive clock supplied to the sensor unit at a constant cycle to generate an image signal representing imaging information of the subject document in main scanning line units. A driving circuit to be output, a signal processing circuit that weights the image signal in units of each scanning line period based on a detection result of the speed detection unit and a driving cycle of the driving circuit, and a weighting unit that is weighted for each scanning line period. A compression circuit for compressing information on the image signal.

According to the present invention, since the compression processing circuit directly performs compression processing on the weighted image data, the signal processing circuit does not need to delay the input image signal by the interpolation processing. .

[0013]

FIG. 1 is a block diagram showing a first embodiment of a scanner device according to the present invention, and FIG. 2 is a timing chart for explaining its operation.

The scanner device according to the present invention comprises a line sensor 1
1, drive circuit 12, speed detection circuit 13, analog signal processing circuit 14, A / D conversion circuit 15, digital signal processing circuit 16, compression circuit 17, memories 18, 19, and recording unit 2.
It is composed of 0. The configuration from the line sensor 1 to the A / D conversion circuit 15 is the same as the configuration of the scanner device shown in FIG. 7. The image signal M0 is output from the line sensor 11 driven by the drive circuit 12, and the analog processing circuit 1
4 and the A / D conversion circuit 15 outputs an image signal M2.

A feature of the present invention is that the digital processing circuit 16 generates a weighting code C representing the weight of each image signal M3 for each scanning line, and supplies it to the compression processing circuit 17 together with the image signal M3. is there. That is, based on the drive timing signal DC and the speed signal VC, the image signal M
When it is determined that the interpolation processing for 2 is necessary, instead of repeatedly outputting the data for one row, a weighting code C indicating that the data for the row is for two rows is added to the compression processing circuit 17. It is configured to be.

The digital processing circuit 16 performs various processes such as contour correction on the image signal M2. At the same time, based on the drive timing signal DC input from the drive circuit 12 and the speed signal VC input from the speed detection circuit 13, an interpolation process or a thinning process is performed for each scanning line to generate an image signal M3 and a weighting code C. I do. In the interpolation processing or the thinning-out processing, the data amount of the image signal M3 is maintained as it is. In the case of performing the interpolation processing, the value of the weighting code C is increased, and in the case of the thinning-out processing, the value of the weighting code is decreased. . The memory circuit 17 is connected to the digital processing circuit 16 and temporarily stores the image signal M2 input from the A / D conversion circuit 5 to the digital processing circuit 16. The digital processing circuit 16 performs the above-described processing on the image signal M2 stored in the memory circuit 17.

The compression circuit 18 converts the image signal M3 into
A compression process based on the weighting code C is performed to generate a compressed image signal M4. The memory circuit 19 includes the compression processing circuit 1
8 and temporarily stores the image signal M3 and the weighting code C input from the digital processing circuit 16 to the compression processing circuit 18. The compression processing circuit 18 performs a predetermined compression process on the image signal M3 and the weighting code C stored in the memory circuit 19. The recording section 20 is composed of a rewritable recording medium such as a semiconductor memory or a magnetic disk having a capacity capable of recording a compressed image signal M4 corresponding to at least one page of the subject document.
And sequentially takes in and records the compressed image signal M4 input from the. The compressed image signal M4 recorded in the recording unit 20
Is transferred to a device such as a personal computer or a facsimile in units of one page.

Here, when the moving speed of the line sensor 11 increases and the period L of the speed signal VC (f) becomes shorter than the imaging period T, as shown in FIG. During T, the rising of the speed signal VC appears twice. At this time, in the image signal G2, for example, information (L3 + L4) for two lines is included in the fourth line as shown in FIG. 3A. The digital processing circuit 16 determines that the image signal G2 at that timing is information (L3 + L4) for two rows based on the number of rising edges of the speed signal VC during the imaging cycle T, and sets the value of the weighting code C to “2”. To "." The compression processing circuit 18 outputs the image signal M during the period in which the value of the weighting code C is set to “2”.
3 is recognized as representing two scanning lines, and a predetermined compression process is performed. For example, if the compression processing circuit 18 uses JPEG (J
oint Photographic Expert Group) algorithm, the image signal M3 is subjected to compression processing in units of 8 × 8 pixels.
Are stored for eight rows. At this time, if the value of the weighting code C is set to “2”, the same image signal M3 is stored in two consecutive rows. In such processing, it is not necessary to interrupt the image signal M3 input in real time, and it is not necessary for the digital processing circuit 16 to hold the image signals M2 for a plurality of rows.

Conversely, when the moving speed of the line sensor 11 becomes slower and the period L of the speed signal VC (s) becomes longer than the imaging period T, as shown in FIG. During T, the rise of the speed signal VC does not appear. At this time, in the image signal G2, FIG.
As shown in (b), for example, the information on the fourth line is missing. The digital processing circuit 16 determines that the image signal G2 at that timing is missing from the number of rises of the speed signal VC during the imaging cycle T, and sets the weighting code C to “0”. The compression processing circuit 18 outputs the image signal M during the period in which the value of the weighting code C is set to “0”.
3 is not subjected to compression processing, and the image information M
Wait for the input of 3.

In the above-described scanner apparatus, even when the interpolation processing is performed on the image signal M2, the processing can be continued without interrupting the image signal M2 input in real time. Is not required.

FIG. 4 is a block diagram showing a second embodiment of the scanner device of the present invention, and FIG. 5 is a timing chart for explaining its operation. In this embodiment,
The case where color imaging is supported is shown.

The scanner device of the present invention comprises a line sensor 2
1, a drive circuit 22, a speed detection circuit 23, an analog signal processing circuit 24, an A / D conversion circuit 25, a digital signal processing circuit 26, a memory 27, and a recording unit 28.

The line sensors 21 are red (R), green (G)
And the light receiving pixel rows 21r, 21g, 21b respectively associated with the respective components of blue and blue (B) are arranged in parallel with each other, and the image signals R0, G0, B0 is output. Each of the light receiving pixel rows 21r, 21g, and 21b itself includes a plurality of light receiving pixels arranged at regular intervals and a shift register that transfers and outputs photoelectric conversion charges accumulated in each light receiving pixel. Is provided with a color filter corresponding to a predetermined color component. The line sensor 21 is mounted such that the longitudinal direction of each of the light receiving pixel rows 21r, 21g, and 21b is the main scanning direction, and is movable in the sub scanning direction with respect to the original document. Here, the light receiving pixel row 21g for obtaining the G component serving as the reference for setting the scanning line density is arranged downstream of the other light receiving pixel rows 21r and 21b in the sub-scanning line direction. That is, in the generation of the luminance signal, R, G,
Since each component of B is synthesized at a ratio of 3: 6: 1, the G component that has the most influence on the luminance signal is used as a reference for setting the scanning line density, and the G component is located at the most downstream in the sub-scanning direction. It is arranged. In such a line sensor 21, since a predetermined gap is provided between the respective light receiving pixel columns 21r, 21g, 21b, the respective light receiving pixel columns 21r, 21r
The areas g and 21b on the original document to be imaged are also shifted by the gap.

The drive circuit 22 generates transfer clocks φr, φg, φb for raising a drive pulse at a constant period T, and transfers the transfer clocks φr, φg, φb to the respective light receiving pixel columns 21r, 21g of the line sensor 21. , 21b. In each of the transfer clocks φr, φg, φb, the rising timing of the drive pulse is １ ／ cycle (T / 3)
Image signals R0, G0, B0
Are continuously and time-divisionally output from the line sensor 21 in line units. Here, regarding each of the image signals R0, G0, B0, the respective light receiving pixel columns 21r, 21r of the line sensor 21
The time difference is included for each color component by an amount corresponding to the shift of the imaging target area of g and 21b. In addition, the drive circuit 22 outputs a drive timing signal DC in which a timing pulse rises in synchronization with the rise of the drive pulse of the transfer clock φg for extracting the G component as a reference for determining the scanning line density. Then, the speed detecting circuit 23 detects the moving speed of the line sensor 21 with respect to the subject document, and outputs a speed signal VC that changes the cycle according to the detected speed.

The analog processing circuit 24 includes the line sensor 2
Three types of image signals R0 and G input in time division from 1
Processes such as sample hold and gain adjustment are time-divisionally performed on 0 and B0 to generate image signals R1, G1, and B1 according to a predetermined format. The A / D conversion circuit 25
Image signals R1 and G input from the analog processing circuit 4
1 and B1 are sampled and held at a timing according to the output operation of the line sensor 21, and the respective sampling values are digitized to generate image signals R2, G2 and B2. The individual processing itself for each color component in the analog processing circuit 24 and the A / D conversion circuit 25 is performed by the analog processing circuit 4 shown in FIG.
And the A / D conversion circuit 5 and the line sensor 21
Image signals R2, G2,
B2 can be obtained.

The digital processing circuit 26 generates an image signal R2,
Various processes such as contour correction are performed on G2 and B2, and the time difference between the color components is corrected. At the same time, in response to the drive timing signal DC input from the drive circuit 22 and the speed signal VC input from the speed detection circuit 23,
The image signal G2 indicating the G component is subjected to interpolation processing or thinning processing in units of one line to generate an image signal G3 and a weighting code C. For the image signals R2 and B2 indicating the R component and the B component, the scanning line density is
Processing is performed to match the scanning line density of the corrected image signal G3 to generate image signals R3 and B3. As a result, image signals R3, G3, and B3 whose time differences are corrected and whose scanning line densities are uniform are generated.

The memory circuit 27 includes a digital processing circuit 26
, And stores the image signals R2, G2, and B2 in units of one row so that the time difference between the color components can be corrected. For example, each of the light receiving pixel rows 21r, 21g of the line sensor 21,
When the gap of 21b is one row, each light receiving pixel column 21
Since the imaging target areas r, 21g, and 21b are shifted from each other by two rows, the image signal R2 corresponding to the R component corresponds to four rows, the image signal B2 corresponding to the B component corresponds to two rows, and the image signal corresponding to the G component. G2 is stored for one line. The recording unit 18 is connected to the digital processing circuit 16 and takes in the image data R3, G3, and B3 generated in the digital processing circuit 16 and records the image data in units of one screen (page units of the subject document).

The compression processing circuit 28 outputs the image signals R3, G
3 and B3 are subjected to compression processing based on the weighting code C to generate compressed image signals R4, G4 and B4. The memory circuit 29 is connected to the compression processing circuit 28 and temporarily stores the image signals R3, G3, B3 and the weighting code C input from the digital processing circuit 26 to the compression processing circuit 28. The compression processing circuit 28 outputs the image signals R3, G3, B3 and the weighting code C stored in the memory circuit 29.
Is subjected to a predetermined compression process. Then, the recording unit 30
Is composed of a recording medium having a capacity capable of recording the compressed image signals R4, G4, B4 corresponding to at least one page of the subject document, and sequentially takes in the compressed image signals R4, G4, B4 input from the compression processing circuit 28. To record.

Each light receiving pixel row 21r of the line sensor 21
When the gap between 21g and 21b is one line, the image signal R
As shown in FIG. 6, 2, G2 and B2 are obtained at timings shifted by two rows for each color component. That is, the image signal G2 obtained from the light receiving pixel 21b arranged on the upstream side of the image signal G2 obtained from the light receiving pixel column 21g arranged on the most downstream side is advanced by two rows, and furthermore, the image signal G2 obtained on the upstream side Signal B2 obtained from the light receiving pixel 21r arranged on the side
Is four lines ahead.

In such a situation, the line sensor 21
When the moving speed of the speed signal VC becomes faster and the period L of the speed signal VC (f) becomes shorter than the imaging period T, as shown in FIG.
The rising of C appears twice. At this time, in the image signal G2, for example, as shown in FIG.
The row contains information (L4 + L5) for two rows. At the same timing, the image signal B2 indicates the seventh row, and the image signal R2 indicates the ninth row, and each includes information (L6 + L7, L8 + L9) for two rows. The digital processing circuit 26 outputs the speed signal VC during the imaging cycle T.
From the number of rising edges of the image signal G2 at that timing
Is information (L4 + L5) for two rows, and the value of the weighting code C is set to “2”. At the same time, information (L4) of the image signals B2 and R2 representing the same fifth row is extracted,
The signal is supplied to the compression circuit 28 as image signals B3 and R3 in association with the image signal G3. As for the image signal G2, since the line sensor 21 is operating in real time, the next information (L6) appears on the following sixth line without a gap. To cope with this, in the image signals B2 and R2, 6
Lines are skipped, and the information (L6) on the seventh line is supplied to the recording unit as image signals B3 and R3.

By the way, in the image signal B2, the second line is
Although the line information (L6 + L7) is included, the digital processing circuit 26 treats the two lines of information (L6 + L7) as it is for one line. When the information (L7) on the seventh row appears in the image signal G2, the image signal B2 indicates that
The information (L6 + L7) on the line is output repeatedly. The digital processing circuit 26 performs such processing by using the image signal R2
The same applies to the information (L8 + L9) on the ninth line.

Conversely, when the moving speed of the line sensor 21 becomes slow and the period L of the speed signal VC (s) becomes longer than the imaging period T, as shown in FIG. During T, the rise of the speed signal VC does not appear. At this time, in the image signal G2, for example,
As shown in FIG. 6B, the information in the fifth row is missing. At the same timing, the image signal B2 indicates the seventh row, and the image signal R2 indicates the ninth row, and the respective information is missing. The digital processing circuit 26 calculates the imaging cycle T
It is determined that the image signal G2 at that timing is missing from the number of rises of the speed signal VC during the period of, and the weighting code C is set to “0”. At the same time, the supply of the image signals B3 and R3 to the compression processing circuit 28 is temporarily stopped for the information (L4) of the image signals B2 and R2 representing the same fifth row. The information (L in the sixth row) is added to the image signal G2.
When 4) appears, the image signal G3 to the compression processing circuit 28
At the same time, the supply of the image signals B2 and R2 to the compression processing circuit 28 is started as the information (L4) in the sixth row as the image signals B3 and R3.

When the eighth row of information (L6) appears after the seventh row of information (L5) in the image signal G2, the digital processing circuit 26 uses the image signal B2 to generate the sixth row of information (L5). Next, the seventh line where information is missing is skipped, and the information (L6) of the eighth line is output to the recording unit 28 as the image signal B3.
Such processing is performed by adding the information (L
The same applies when the information (L8) on the 10th line appears following 7).

In the digital processing circuit 26, while the rising edge of the speed signal VC appears once in the imaging period T, the digital processing circuit 26 does not perform any interpolation or thinning processing as shown in FIG. Processing circuit 6
Is the same as

In the above-described scanner device, similarly to the first embodiment, the image signals R3, G3, and B3 are input in real time during interpolation processing on the image signals R3, G3, and B3.
Processing can be continued without interrupting G3 and B3. A weighting code C is set for the G component at which the output timing of the image signal is the latest, and the scanning line density is set for the other R and B components so as to match the G component. I have. For this reason,
Image signals that need to be temporarily held during the processing of the image signals R3, G3, B3 can be minimized, and the memory 27 connected to the digital processing circuit 26 can be used efficiently.

[0036]

According to the present invention, it is possible to continue processing an image signal input in real time without using a large-capacity memory circuit. Therefore, the operation speed can be improved while simplifying the circuit configuration. Further, since the compressed image signal is stored in the recording unit, the time required for transferring the image signal from the storage unit to various computer devices can be reduced, or the connection line can be simplified. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a first embodiment of a scanner device according to the present invention.

FIG. 2 is a timing chart for explaining the operation of the first embodiment.

FIG. 3 is a diagram illustrating a configuration of an image signal according to the first embodiment.

FIG. 4 is a block diagram showing a second embodiment of the scanner device of the present invention.

FIG. 5 is a timing chart for explaining the operation of the second embodiment.

FIG. 6 is a diagram illustrating a configuration of an image signal according to a second embodiment.

FIG. 7 is a block diagram showing a configuration of a conventional hand scanner device.

FIG. 8 is a timing chart for explaining the operation of the conventional hand scanner device.

[Explanation of symbols]

 1, 11, 21 Line sensor 2, 12, 22 Drive circuit 3, 13, 23 Speed detection circuit 4, 14, 24 Analog processing circuit 5, 15, 25 A / D conversion circuit 6, 16, 26 Digital processing circuit 7, 17, 19, 27, 29 Memory circuit 8, 20, 30 Recording unit 11r, 11g, 11b Light receiving pixel column 18, 28 Compression processing circuit

Continuation of the front page (72) Inventor Hideya Ohashi 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Inside Sanyo Electric Co., Ltd. (72) Inventor Shinya Fujii 2-5-5-1 Keihanhondori, Moriguchi-shi, Osaka No. SANYO Electric Co., Ltd. F-term (reference) 5C072 AA01 BA19 CA07 FB08 FB23 MA01 MB01 MB02 UA20

Claims (4)

[Claims] 1. A sensor unit which is relatively moved in a sub-scanning direction with respect to a subject document, and captures an image of the subject document in main scanning line units, and a speed detection unit which detects a relative speed of the sensor unit with respect to the subject document. A drive circuit that supplies a drive clock to the sensor unit at a constant cycle to output an image signal representing imaging information of the subject document in units of main scanning lines, a detection result of the speed detection unit, and the drive A signal processing circuit that weights the image signal in units of each scanning line period based on a driving cycle of the circuit; and a compression circuit that performs information compression processing on the image signal weighted in each scanning line period. A scanner device comprising: 2. The method according to claim 1, wherein the signal processing circuit increases a weight for the image signal when a detection result of the speed detection unit is shorter than a driving cycle of the driving circuit, and increases a weight for the image signal when the detection result is longer. The scanner device according to claim 1, wherein weighting is reduced. 3. The sensor unit according to claim 2, wherein the plurality of light receiving pixels associated with the same color component are arranged in the main scanning direction across the subject document, and the plurality of light receiving pixels associated with different color components are provided. 2. The scanner device according to claim 1, wherein the columns are arranged in the sub-scanning direction to output an image signal including a plurality of color components. 4. The signal processing circuit according to claim 1, wherein a scanning line density of an image signal corresponding to a light receiving pixel array arranged on the most downstream side in a relative moving direction of the sensor unit with respect to the subject document is determined. 4. The scanner device according to claim 3, wherein the scanning line density corresponding to the light receiving pixel column arranged on the upstream side is adapted.