JPH05176111A - Automatically starting bit retrieving device for ccd - Google Patents

Abstract

PURPOSE:To eliminate the need for the troublesome fitting position adjustment of an image sensor whose exactness is hardly expected by successively discharging pixel signals subsequent to the positioning of a set picture element from a CCD when the counted value of scanning clocks reaches a set value. CONSTITUTION:A storing means 6 stores the scanning starting pixel position information of the valid pixel area of the CCD. According to a scanning starting signal, a first pixel discharging means 7 starts the discharge of the pixel signal of the CCD and successively discharges the picture elements until the picture element preceding to the scanning starting pixel position in the valid pixel area according to the scanning clocks corresponding to the stored scanning pixel element position information. Then, a second pixel discharging means 8 counts the scanning clocks and when the counted value reaches the set value, the pixel signals subsequent to the set pixel position are successively discharged from the CCD.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CCD start bit automatic retrieval device.

[0002]

2. Description of the Related Art Conventionally, as an image sensor, for example, a one having a one-dimensional CCD 1 and a lens 2 provided in a housing 3 as shown in FIG. 8 has been used, and the CCD 1 uses a lens 2 to photograph an object such as a card or a passbook. A medium 5 such as is imaged. CC
The effective pixel area A in the longitudinal direction of D1 is set in advance by the user, and the range corresponding to this effective pixel area A becomes the effective widthwise reading area B of the medium 5.

The medium 5 is carried by the carrier in the direction perpendicular to the longitudinal direction of the CCD 1, and the CCD 1 is driven by the clock from the CCD drive circuit. Then, in the CCD 1, an image of the effective widthwise reading area B on the reading line on the medium 5 is imaged on the effective pixel area A by the lens 2 and arranged in a line in the longitudinal direction. Each of them is converted into and accumulated in each of the electric charges, transferred to the shift register in parallel through the shift gate, and then sequentially discharged from the shift register in series by the scanning clock.

The image sensor 4 is mounted on the CCD
The pixel signal discharged from the CCD 1 is mechanically adjusted by a person so that the effective pixel area A of No. 1 and the effective reading area B in the width direction of the medium 5 coincide with each other. For example, as shown in FIG. 9, pixel signals from the nth to (n + 1024) th photoelectric conversion elements in the pixel signal discharge order are used as valid signals. It should be noted that the diagonal lines in FIGS. 9 and 10 indicate valid pixel signals in the shift register.

[0005]

The image sensor 4 described above is to be solved.
Since the mounting position is mechanically adjusted by a person so that the effective pixel area A of the CCD 1 and the effective width-direction reading area B of the medium 5 coincide with each other, the adjustment of the mounting position is troublesome. In addition, it is difficult to accurately match the effective pixel area A of the CCD 1 with the effective widthwise reading area B of the medium 5, and the photoelectric conversion within the range that accurately corresponds to the effective widthwise reading area B of the medium 5 in the CCD 1. It becomes difficult to obtain a pixel signal by the conversion element.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the above-mentioned drawbacks and provide an automatic start bit retrieval device for a CCD, which eliminates the troublesome and inaccurate attachment position adjustment of the image sensor.

[0007]

In order to achieve the above object, the present invention uses a storage means 6 for storing scan start pixel position information of an effective pixel area of a CCD as shown in FIG. A first pixel signal is started to be discharged from the CCD, and the pixel signal is sequentially discharged to a pixel one pixel before the scanning start pixel position in the effective pixel area according to the scanning start pixel position information stored in the storage means 6 according to the scanning clock. Pixel signal discharging means 7 and second pixel signal discharging means 8 for sequentially discharging pixel signals after the set pixel position from the CCD when the scanning clock is counted and the count value reaches a set value. It is equipped with and.

[0008]

The scanning start pixel position information of the effective pixel area of the CCD is stored in the storage means 6, and the first pixel signal discharging means 7 starts discharging the pixel signal of the CCD by the scanning start signal and is stored in the storage means 6. According to the scanning start pixel position information, the pixel signals are sequentially discharged according to the scanning clock up to the pixel one pixel before the scanning start pixel position in the effective pixel area. Then, the second pixel signal discharging means 8 counts the scanning clock, and when the count value reaches the set value, the pixel signals after the set pixel position are sequentially discharged from the CCD.

[0009]

FIG. 2 shows an embodiment of the present invention, and FIG. 4 shows a timing chart of this embodiment. The CCD 1 is a CCD of the image sensor 4 and is driven by a CCD drive circuit, and an image of an effective widthwise reading area B on a reading line on the medium 5 is formed by a lens 2 on an effective pixel area A in the longitudinal direction. .. In this CCD 1, a plurality of bits of photoelectric conversion elements arranged in a line in the longitudinal direction convert incident light into electric charges and accumulate the electric charges, which are transferred in parallel to a shift register through a shift gate, and then by a scanning clock ISCK. Main scanning is performed by sequentially discharging pixel signals from the shift register in series.

The pixel signal discharged from the CCD 1 is amplified by the amplifier 11, A / D converted by the A / D converter 12, and output to the logic circuit 13. In this embodiment, the scan start pixel position of the effective pixel area A in the longitudinal direction corresponding to the effective widthwise reading area B of the medium 5 in the CCD 1 is measured in advance in the test mode to measure E ² PRO.
Write in M14.

In the test mode, the medium 5 shown in FIG.
A scanning start pixel position measuring medium 15 as shown in (a) is used, and in the scanning start pixel position measuring medium 15, the effective width direction reading area B is black and other than the effective width direction reading area B. Area is white. The scanning start pixel position measuring medium 15 is conveyed in a direction perpendicular to the longitudinal direction of the CCD 1 by a conveying machine and illuminated by a light source on the reading line, and the reflected light image is photoelectrically converted by the CCD 1.

The CCD 1 is driven by the clock from the CCD drive circuit, and an image of the effective widthwise reading area B on the scanning start pixel position measuring medium 15 is imaged by the lens 2 on the effective pixel area A in the longitudinal direction. Are converted into electric charges by photoelectric conversion elements of a plurality of bits arranged in a line in the longitudinal direction and accumulated, and these are transferred in parallel as pixel signals to a shift register through a shift gate, and then from a CCD drive circuit. Scan clock I
SCK sequentially shifts serially from the shift register and discharges. The CCD 1 repeats such an operation, and discharge of the pixel signal is started for each line by the scanning clock ISCK.

The scanning start pulse / STP (/ means inversion) and the pixel signal from the CCD 1 are shown in FIGS.
The pixel signal from the CCD 1 has a waveform as shown in FIG. 1 through the amplifier 11 and the A / D converter 12
It is binarized by 3 and output to the CPU 16. As shown in FIG. 3D, the binarized data from the logic circuit 13 becomes low level in the effective black reading area B in the width direction of the scanning start pixel position measuring medium 15 and becomes the scanning start pixel position measuring medium. It becomes high level in the white part other than the effective width direction reading area B of 15, and the scanning start pulse / STP
The time T from the trailing edge to the trailing edge of the binary data from the logic circuit 13 is the effective pixel area in the longitudinal direction of the CCD 1 corresponding to the black effective width direction reading area B of the scanning start pixel position measuring medium 15. It is determined by the scanning start pixel position of A.

The CPU 16 uses the scan start pulse / STP and the binary data from the logic circuit 13 to set the time T.
By measuring the time, the scanning start pixel position of the effective pixel area A in the longitudinal direction of the CCD 1 is detected and written in the E ² PROM 14.

FIG. 5 shows the configuration of the logic circuit 13. The output signal of the A / D converter 12 is a binarization circuit 17
Is binarized by the input signal to the latch circuit 18, and the test mode signal / TST1 is set to the latch circuit 1 in the test mode.
9 and the CPU 16. The latch circuit 19 is enabled when the test mode signal / TST1 becomes active, and outputs the latched scanning start pulse / STP to the latch circuit 18. The latch circuit 18 is enabled by the output signal of the latch circuit 19 and latches the binarized data from the binarization circuit 17 and outputs it to the CPU 16.

As shown in FIG. 6, the CPU 16 detects whether or not the external test mode signal / TST1 has become active to enter the test mode, and the test mode signal / TST1
When TST1 becomes active, it is detected whether or not the scan start pulse / STP has fallen. When the scan start pulse / STP falls, the CPU 16 counts the time T by counting the scan clock ISCK by the counter during the time until the binarized data from the latch circuit 18 falls. The value of the counter is converted into a pixel number at the scanning start pixel position of the effective pixel area A in the longitudinal direction of the CCD 1 (the number of each pixel for generating a pixel signal in the CCD 1 is added in the scanning order) n and written in the E ² PROM 14.

After the above test mode is completed, the normal mode is entered. In this normal mode, the CPU 16 controls the CCD drive circuit as shown in FIG. 7 to free run the CCD 1. On the CCD 1, an ordinary medium 5 other than the scanning start pixel position measuring medium 15 is imaged by the lens 2. The effective pixel area A in the longitudinal direction of the CCD 1 is the medium 5
Corresponding to the effective width-direction reading area B, and the mounting position of the image sensor 4 is not adjusted.
The user sets the number of pixel signals required by the CCD 1 to the number of required pixel signals by the setting unit and outputs the set value to the CPU 16. For example, it is necessary among the pixel signals for one line discharged from the CCD 1. Then, the numbers of the pixel signals in the discharge order are set from the Nth to (N + 1024) th and are output to the CPU 16.

The medium 5 is carried by the carrier in the direction perpendicular to the longitudinal direction of the CCD 1, and the CCD 1 is driven by the clock from the CCD drive circuit. Then, in the CCD 1, an image of the effective widthwise reading area B on the reading line on the medium 5 is imaged on the effective pixel area A by the lens 2 and arranged in a line in the longitudinal direction. Each of them is converted into and accumulated in each of the electric charges, transferred to the shift register in parallel through the shift gate, and then sequentially discharged from the shift register in series by the scanning clock.

As shown in FIG. 7, the CPU 16 detects whether or not the scan start pulse STP is activated,
When the scanning start pulse STP becomes active, the count number of the counter is reset. Next, the CPU 16
Controls the CCD drive circuit to drive the CCD 1 by generating a scan clock ISCK having a higher frequency than the scan clock SCK from the outside, as shown in FIG.

The CPU 16 counts the number of discharged pixel signals by counting the scanning clock ISCK by the counter, and the count number of this counter is (n-
Judge whether or not 1) has been reached. When the number of counts of the counter reaches (n-1), the CPU 16 causes the CCD drive circuit to stop the output of the scanning clock ISCK and the CCD 1
The pixel signal discharge of No. is stopped, and it is determined whether or not the count number of the counter reaches (N-1) by N input by the user from the setting unit.

Here, the first to (n-1) th pixel signals discharged from the CCD 1 are discharged as invalid pixel signals at a timing earlier than the normal pixel signal output timing, and then shown in FIG. As described above, the discharge of the pixel signals is stopped while the Nth and subsequent pixel signals are discharged from the CCD 1.

In the CPU 16, the count number of the counter is (N
-1), the scan clock ISCK is supplied to the CCD drive circuit as shown in FIG.
The pixel signal discharge from the CCD 1 is restarted by generating it in synchronization with K and outputting it to the CCD 1. Therefore, the Nth and subsequent pixel signals are immediately discharged from the CCD 1 as regular pixel signals.

By repeating the above operation, the Nth and subsequent pixel signals set by the user for each line are discharged as regular pixel signals from the CCD 1. As described above, the first to (n-1) th pixel signals are discharged from the CCD 1 for each line as an invalid pixel signal in an early stage, and then temporarily stopped and the Nth and subsequent pixels set by the user. By ejecting the pixel signal as a regular pixel signal, it is unnecessary to adjust the mounting position because the image sensor 4 is troublesome and difficult to be accurate.

[0024]

As described above, according to the present invention, the storage means for storing the scanning start pixel position information of the effective pixel area of the CCD and the scanning start signal to start the discharge of the pixel signal of the CCD are stored in the storage means. Based on the stored scanning start pixel position information, first pixel signal discharging means for sequentially discharging pixel signals according to the scanning clock up to the pixel one pixel before the scanning start pixel position in the effective pixel area, and the scanning clock are counted. And the second pixel signal discharging means for sequentially discharging the pixel signals after the set pixel position from the CCD when the count value reaches the set value, the image sensor is troublesome and difficult to be accurate. No need to adjust the mounting position.

[Brief description of drawings]

FIG. 1 is a block diagram showing the present invention.

FIG. 2 is a block diagram showing an embodiment of the present invention.

FIG. 3 is a diagram for explaining the same embodiment.

FIG. 4 is a timing chart of the same embodiment.

FIG. 5 is a block diagram showing a part of the embodiment.

FIG. 6 is a flowchart showing a test mode processing routine of the CPU in the embodiment.

FIG. 7 is a flowchart showing a normal mode processing routine of the CPU in the embodiment.

FIG. 8 is a schematic diagram illustrating an example of an image sensor and a medium.

FIG. 9 is a diagram showing a state before a pixel signal of a CCD is discharged.

FIG. 10 is a diagram showing a state when the pixel signal discharge of the CCD is started.

[Explanation of symbols]

 6 Storage Means 7 First Pixel Signal Ejection Means 8 Second Pixel Signal Emission Means

Claims (1)

[Claims] 1. A storage means for storing scanning start pixel position information of an effective pixel area of a CCD, and a scanning start pixel position information stored in the storage means for starting discharge of a pixel signal of the CCD by a scanning start signal. First pixel signal discharging means for sequentially discharging pixel signals in accordance with a scanning clock up to one pixel before the scanning start pixel position in the effective pixel area, and counting the scanning clock, the count value reaches a set value. Thus, the automatic start bit retrieval device for the CCD, further comprising: second pixel signal discharging means for sequentially discharging pixel signals after the set pixel position from the CCD.