JPS62208751A - Image correction circuit - Google Patents

Abstract

PURPOSE:To electrically and easily correct the deviation in the subscanning direction by deviating the shift pulse sending timing as the mounting position of an image sensor is adjusted apparently if the deviation takes place in the subscanning direction at the joints of plural image sensors. CONSTITUTION:A light source 8 projects an original 9 and sends the video of a line 1 written on the original 9 to a CCD 3 via a lens 2 and to a CCD 5 via a lens 4 respectively. Shift pulse generating circuits 10, 11 send a shift pulse being a timing pulse extracting the electric charge by the reception of the CCDs 3, 4 to the CCDs 3, 4 respectively. A shift pulse control circuit 12 adjusts the electric charge extraction timing of the CCDs, 3, 5 and sends the result to the circuits 10, 11 respectively. A read position information setting circuit 13, for example, based on the difference of the density between the CCDs 3 and 5 outputted to a printer, changes the setting value to give the instruction of the change in the shift pulse sending timing to the circuit 12, which controls the circuits 10, 11 to adjust the electric charge extracting timing of the CCDs 3, 5.

Description

[Detailed Description of the Invention] [Summary] When reading images using multiple image sensors, in order to prevent image quality from deteriorating due to misalignment of the joints of the image sensors, it is necessary to prevent minute misalignments in the sub-scanning direction that are particularly difficult to manually adjust. can be electrically adjusted by setting an adjustment value from the density difference of each CCD output.

[Industrial application field]

The present invention relates to an image reading device that reads images by arranging a plurality of image sensors in a line, and more particularly to an image correction circuit that corrects deviations in the sub-scanning direction at the joints of the image sensors.

With the development of the information society, various image reading devices have been developed and used. Some of these image reading devices use a CCD as an image sensor. By the way, CC
There is a limit to the size of D, and when reading a small size image, one COD suffices, but when reading a large size image, multiple CODs are used and these are added together.

For example, an image reading device that reads A1 drawings at a reading density of 400 dots/inch uses two 5-bit CODs, aligns these two CCDs mechanically, and reads a 10,000-bit COD. It is constructed as if you were using one.

However, when using a plurality of CODs, it is necessary to manually and mechanically align the positions, but since it is difficult to correct minute positional deviations, it is desirable to be able to correct them electrically on a circuit.

[Conventional technology]

FIG. 5 is a diagram illustrating the positioning of a conventional CCD.

For example, as shown in FIG.
It is assumed that the CCD 5 reads the remaining half of the line 1 via the lens 4. In this case, it is easy to mechanically fix the distance between the document and the CCD accurately, but CCD3 and CCD5
Between them, a shift occurs in the read data depending on their relative positions.

That is, for example, as shown in FIG.
Even if D5 is attached parallel to line 1, if there is a deviation in its position with respect to the document feeding direction, the read line will be deviated in the sub-scanning direction even if it is parallel.

In addition, as shown in Fig. 5 (C1), one read line is inclined with respect to the other line and the seams overlap, as shown in Fig. 5 (d), the line is inclined and separated from each other, and a combination of these The following condition occurs.

Conventionally, the overlap or separation of the line 1 and the inclination in two directions,
While observing the output of CCDs 3 and 5 for deviation in the sub-scanning direction, check the printed board unit 6 and CC with CCD 3 attached.
Adjustments were made by manually moving the printed board unit 7 to which D5 was attached.

[Problem that the invention seeks to solve]

As mentioned above, conventional adjustment is done manually, but it is relatively easy to adjust inclination, overlapping, or separated states, but the deviation in the sub-scanning direction is particularly small. For example, if there is a deviation of about half the l line, manual adjustment is extremely difficult.

In view of these problems, the present invention is designed to electrically correct the deviation in the sub-scanning direction by shifting the timing of the shift pulses supplied to the CCDs 3 and 5.

[Means for solving problems]

FIG. 1 is a block diagram of the principle of the present invention.

The original 9 is conveyed in the direction shown by the arrow A, and the light source 8 illuminates the original 9, and sends an image of the line 1 written on the original 9 to the CCD 3 via the lens 2, and to the CCD 5 via the lens 4.

The shift pulse generation circuit 10 generates a shift pulse, which is a timing pulse for taking out the electric charge generated by the light received by the CCD 3, as C0.
D3, and the shift pulse generation circuit 11 sends a shift pulse to the CCD 5.

The charges sent out by the CCDs 3 and 5 by the shift pulses are processed by a circuit (not shown) to print cotton on a printer, for example.

The shift pulse control circuit 12 adjusts the charge extraction timing of the CCDs 3 and 5, and controls the shift pulse generation circuit 1, respectively.
Send to 0 and 11. The reading position information setting circuit 13 instructs the shift pulse control circuit 12 to change the shift pulse sending timing by changing a set value based on, for example, the difference in density between the CCD 3 and the CCD 5 output to the printer.

Based on the setting value instructed by the reading position information setting circuit 13,
The shift pulse control circuit 12 is the shift pulse generation circuit 10
and 11 to adjust the charge extraction timing of the CCDs 3 and 5.

[Effect]

With the above configuration, there is a difference in the mounting status of CCDs 3 and 5, and when shift pulses are sent out at the same timing, if a shift occurs in the sub-scanning direction at the line joint, the apparent difference is that of the upper CCD 3 or 5. As with the installation, the shift pulse sending timing can be changed without changing the position.

〔Example〕

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

The original 9 is conveyed in the direction shown by the arrow A, and the light source 8 illuminates the original 9, and sends an image of the line 1 written on the original 9 to the CCD 3 via the lens 2, and to the CCD 5 via the lens 4.

A video clock is input from terminal B to the CCDs 3 and 5 to convert parallel signals read by shift pulses into serial signals and read them out, and is supplied as a clock to the counter 22.

Further, a shift pulse is input from the terminal C and is supplied to the shift pulse generation circuit 11 and the counter 22.

The dip switch 23 is the reading position information setting circuit 1 in Figure 1.
This is an example of No. 3, and the switch settings are performed by the method described later. Further, the counter 22 is an example of the shift pulse control circuit 12 shown in FIG. 1, and counts the numerical value specified by the dip switch 23.

The shift pulse input from the terminal C has its polarity inverted by the inverter 21 of the shift pulse generation circuit 11, and after increasing the switching speed by the resistor 20 and capacitor 19, is supplied to the CCD 5 by the driver 18.

The shift pulse supplied to the counter 22 at the same time causes the counter 22 to count the value indicated by the dip switch 23.
The signal is then delayed by the count value and sent to the shift pulse generating circuit 1o, the polarity is inverted by the inverter 17, the switching speed is increased by the resistor 16 and the capacitor 15, and then the driver 14 supplies the signal to the CCD 3.

FIG. 3 is a diagram for explaining the shift pulse, and FIG. 4 is a diagram for explaining the density depending on the timing of the shift pulse.

Now, let us consider the case where the CCDs 3 and 5 are installed shifted by one line in the sub-scanning direction, and explain the density of images obtained from the CCDs 3 and 5 depending on the supply timing of the shift pulse at this time.

Let the shift pulse supplied to CCD3 be ■, and CCD5
When the shift pulses supplied to .
Assuming that the CCD 3 reads as indicated by the diagonal lines, the output level of the CCD 3 at this time is the maximum black level as shown by ■ in Fig. 4(b), and the output of the CCD 5 is the lowest black level (white). .

Here, if the shift pulse ■ is delayed from the shift pulse ■ by a time t as shown in FIG. Assuming that 1/2 line is fed, the difference in the mounting positions of CCDs 3 and 5 is only 1 as shown in Figure 4 (C).
This means that the line has been shortened by 2 lines.

At this time, the difference between the output level of the CCD 3 and the output level of the CCD 5 is as shown in FIG. 4(d), where the output level (2) of the CCD 5 is half the black level of the output level (2) of the CCD 3.

The outputs of CCDs 3 and 5 are converted into digital values by an A/D conversion circuit, and the digital values represent the density. It is easy to output this digital value to a printer and see the difference in density.

By looking at the digital values output to this printer, −
It is sufficient to adjust the difference t in the timing of the 1-ft pulse. That is, the set value of the dip switch 23 can be determined. For example, if CCDs 3 and 5 of bit 5 are shifted by 1/2 line, and the video clock is 5100 pulses, it is sufficient to set a 255° pulse with a dip switch.

〔Effect of the invention〕

As described above, the present invention is an image reading device that uses a plurality of CCDs, and when the CODs are misaligned from each other in the sub-scanning direction, the misalignment can be easily corrected.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a block diagram of a circuit showing an embodiment of the present invention, Fig. 3 is a diagram explaining shift pulses, and Fig. 4 is based on the timing of shift pulses. FIG. 5 is a diagram illustrating the positioning of a conventional CCD. In the figure, ■ is a line, 2.4 is a lens, and 3.5 is a CC.
D, 6.7 is a printed board unit, 8 is a light source,
9 is a document, 10.11 is a shift pulse generation circuit, 12 is a shift pulse control circuit, 13 is a reading position information setting circuit, 14 and 18 are drivers, 17.21 is an inverter,
22 is a counter, and 23 is a dip switch. (n'J■-Go]-
−−←−−−−−“l− ; ■−2!1−−4−−−−−−−Rooooo, −Shift pulse eye membrane J ro diagram Figure 3 Shift pulse Zn> 7” −Roll JKE *i ton B
8T15Figure 4

Claims (1)

[Scope of Claims] An image reading device that reads images by arranging a plurality of image sensors in a line, comprising: a setting means (13) for instructing the sending timing of a shift pulse to be supplied to each image sensor;
) is a control means (
12); and shift pulse generating means (10, 11) for transmitting a shift pulse to each image sensor at the timing at which the control means (12) transmits the shift pulse.