JPS6312431B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION An image information reading device including a solid-state line image sensor is manually sub-scanned to obtain an image signal corresponding to a required image information area on a document. Manual sub-scanning readers offer many other advantages, such as eliminating wasted copy paper that can occur when copying originals using regular copiers. Research on devices is progressing, and the applicant company has made many proposals for this type of device (see, for example, the specification of Japanese Patent Application No. 15349/1983).

However, in a reading device (image signal generating device) in which sub-scanning is performed manually, variations occur in the sub-scanning speed, and as a result, the scanning line spacing in the recorded image becomes uneven, causing image distortion in the recorded image. The problem is that it causes

In order to solve the above problems, in a manual sub-scanning type image signal generator, for example, as shown in FIG. Timing pulse generator TPG that can generate pulses
Provided with the timing pulse generator TPG mentioned above
The reading of image information from the solid-state image sensor 9 may be started by the timing pulse generated by the timing pulse, or as shown in FIG.
Two line image sensors S ₁ and S ₂ are arranged in parallel in a direction perpendicular to the sub-scanning direction, and the same image signal as the image signal read by one of the two line image sensors S ₁ is sent to the line image sensor S. Attempts have been made to measure the time from line image sensor _S2 to reading, and to control the reading cycle of line image sensor _S1 based on the measurement results.

However, in the apparatus shown in FIG.
Since timing pulses are no longer generated from the signal generator 3 in the timing pulse generator TPG, such a device cannot read the original without contacting the original. In addition, there were problems in terms of operability, such as the need to be careful not to let the rotating disk 2 rise above the document 0.

In FIG. 1, 1 is the aircraft body, 2a is a timing pulse generation pattern, 4 is a running roller, 5 and 6 are illumination lamps, 7 is a reading window, and 8
is an imaging optical system.

In addition, in the device shown in the second diagram above, the positional accuracy of the parallel arrangement of the two line image sensors S ₁ and S ₂ affects the image quality, and a large capacity random access memory (RAM) is required for implementation. This was a hindrance to lowering the price of the device. FIG. 3 is a block diagram for explaining the problems of the device shown in FIG.
is a clock controller, PSG is a pulse generator, and m-bit line image sensor S ₁ ,
S ₂ is 2 at a predetermined distance d on document 0.
A pulse generator generates a pixel information signal (image signal) corresponding to the image information at the positions of parallel lines A and B on the book.
Occurs under the control of pulses supplied by the PSG.

Image signals for one line successively sent out from the line image sensor _S1 are stored line by line in the random access memory RAM via the central control unit CPU, and are stored line by line from the random access memory RAM. The storage operation of the image signal in units of one line in the random access memory RAM and the operation of reading out the image signal in units of one line from the random access memory RAM are (m bits x n lines). ) After the first written image signal is read out and output to the output terminal OUT, the image signal of the first line is stored. The (n+1)th image signal is written to the previously stored address, and so on, the addresses of the random access memory are used cyclically for writing and reading.

The arithmetic circuit AU processes the image sensor at regular intervals.
The similarity of the information between the image signal read from _S2 and the image signals of all lines stored in the random access memory RAM is calculated, and the line showing the maximum similarity is the one after the start of the comparison operation. Find out what number it is and give that value to the clock controller CCR. clock controller
The CCR operates the pulse generator PSG so that the period of the sampling clock pulse of the line image sensor _S1 becomes larger or smaller depending on whether the above-mentioned value is larger or smaller than a predetermined value. Control. In FIG. 2, 8 indicates an imaging optical system, 0 indicates a document, and arrow Y indicates a sub-scanning direction.

In the conventional device shown in the second figure having the configuration shown in the third figure, the random access memory RAM
A relatively large-capacity device is required, and it also has the problems mentioned above, such as the two line image sensors S ₁ and S ₂ being arranged with strict parallelism. It is.

The present invention uses a two-dimensional image sensor and a simple storage device to configure an image signal generating device that does not have the drawbacks of conventional ones and solves the above-mentioned problems. The image signal generating device of the present invention will be explained in detail with reference to the drawings.

FIG. 4 shows 2 in the image signal generation device of the present invention.
It is a perspective view showing the correspondence of the image information reading position of the dimensional image sensor IS and the document 0, in which 8 is an imaging optical system, Y is an arrow indicating the sub-scanning direction, and A' and B' indicate positions on the two-dimensional image sensor IS where image information at positions A and B in the document 0 is to be read by the two-dimensional image sensor IS.

As the two-dimensional image sensor, a CCD two-dimensional image sensor or another type may be used. The sub-scanning direction Y in FIG.
This shows both the sub-scanning direction and the sub-scanning direction, which is performed by moving relative to the

FIG. 5 is a block diagram of the image signal generating device of the present invention. In FIG. 5, IS is a two-dimensional image sensor, G ₁ and G ₂ are gate circuits, and SR _a is a first
, SR _b is the second shift register, DIC is the differencer, ADD is the adder, JC is the judgment circuit, CCR is the clock controller, and PSG is the pulse generator. In the circuit arrangement shown in FIG. 3, the two line image sensors S ₁ and S ₂ in the circuit arrangement shown in the block diagram of the conventional example shown in FIG. 3 are two-dimensional image sensors IS, and The central control unit CPU and random access memory RAM are formed into gate circuits G ₁ and G ₂ and first and second shift registers SR _a and SR _b .

An imaging optical system (fourth
The optical image of the image information of the document 0 imaged by the image sensor 8 in FIG. 8 is photoelectrically converted in the two-dimensional image sensor IS, and is output as an image signal of n lines with m bits per line, for example.

6a to 6g are timing charts for explaining the operation of the circuit arrangement shown in FIG. 5, and _FIG. T in the figure represents the reading cycle. 2D image sensor IS
By applying the optical image of the original over a period of γ _a to Full pixel shift pulse like
The signals are transferred all at once to a shift register (not shown) in the two-dimensional image sensor IS by P _a .

Next, among the charges transferred as described above to the shift register in the two-dimensional image sensor IS, the charges to form a pixel information signal of a specific line at the position indicated by A' in FIG. The pixel information signal of a specific line in the shift register storing the column is read out by the pulses P _b and P _c shown in FIG. It is stored in the first shift register SR _a via _G1 .

The opening and closing operations of the gate circuit _G1 are controlled by gate pulses from the pulse generator PSG, and the first shift register SR _a is also controlled by the pulse generator.
Operation is regulated by pulses supplied from the PSG. From the pulse generator PSG, a gate circuit _G2 , a second shift register _SRb , which will be described later,
Various pulses are also generated to control the operations of the differentiator DIC, adder ADD, decision circuit JC, etc.

The first shift register SR _a includes a plurality of (2<l<n) unit shift registers SR _a1 , SR _a2 ...( The _first shift register SR _a has two shift registers in successive read cycles.
Pixel information signals of a specific line of the dimensional image sensor IS are accumulated sequentially, and in the (l+1)th reading cycle, they are accumulated in the unit shift register SR _a1 of the first shift register SR _a in the first reading cycle. The m-bit pixel information signal is transferred to the shift register SR _al of the first shift register SR _a .
is output as an image signal to the output terminal OUT.

Further, the m-bit pixel information signal sent from the shift register _{SR al} of the first shift register SR a is sent to the output terminal OUT as described above, and at the same time, it is sent to the output terminal OUT via the gate circuit G ₂ . It is also accumulated in the second shift register SR _b . The first shift register SR _a has a storage capacity of m bits and the second shift register SR _b has a storage capacity of m bits.
When the m-bit pixel information signal in SR _al has been transferred, the gate circuit G ₂ transfers the m-bit pixel information signal in the second shift register SR _b
The m-bit pixel information signal in the second shift register SR _b circulates through the second shift register SR _b .

Note that the accumulated information in the second shift register SR _b is obtained by inputting a new pixel information signal in the first shift register SR _a to the second shift register SR _b via a gate circuit _G2 . Gate circuit G ₂
When the shift register SR2 is switched, the output side of the second shift register _SR2 is opened by the gate circuit _G2 , so that it is automatically lost.

Now, the above-mentioned gate circuit G ₁ controls the pixels of each line sequentially read out from the two-dimensional image sensor IS, except for the period in which the pixel information signal of a specific line is supplied to the first shift register SR _a in each reading cycle. The circuit is switched so that the information signal can be given as one input to the difference device DIC, and the other input to the difference device DIC is provided as the second input.
is the output signal of shift register SR _{b of}
Calculate the difference between each pixel in the pixel information signal of a specific line in the dimensional image sensor and each pixel in the sequential pixel information signal following the pixel information signal of the specific line of the two-dimensional image sensor in the current reading cycle. and then feeds it to the adder ADD.
Figures 6e and 6f show pulses P c for reading out pixel information signals of successive lines following a specific line set in the two-dimensional image sensor IS from each shift register in the two-dimensional image sensor IS _. , P _d (m
Figure 6g shows the clock pulse.
It shows P _f .

Now, in a reading cycle that starts at a certain time (for example, time t ₀ in FIG. 6), the image information at the position of line A in document 0 shown in FIG. Suppose it is read,
In addition, the two-dimensional image sensor IS and the document 0 are connected to the fourth
Assuming that sub-scanning is performed relatively in the direction of arrow Y in the figure, the position of line A on document ₀ will be The position on the two-dimensional image sensor from which image information can be read is parallel to line A' shown in FIG. 4, and from line A' to line B' during each reading period. The position is shifted by a distance determined by multiplying the distance traveled by the document 0 by the magnification of the imaging optical system 8 by the sub-scanning.

Therefore, in the reading cycle started at time t ₀ described above, the position of line A' on the two-dimensional image sensor IS that was reading image information at the position of line A on document 0 is changed to the position of line A' on the two-dimensional image sensor IS.
If this is the position where a pixel information signal of a specific line determined in advance is to be generated, then time t ₀
The first shift register SR a is read by the two-dimensional image sensor IS in the reading cycle started _at
Original 0 stored in shift register SR _al in units of
The pixel information signal at the position of line A in is (l-1)
l started after repeated read cycles
In the read cycle, the first shift register SR _a
Since it is transferred from the unit shift register SR _al to the second shift register SR _b via the gate circuit G ₂ ,
The pixel information signal transferred to the second shift register SR _b is the pixel information signal at the position of the line A of the original 0 at the reading cycle l reading cycles earlier than the reading cycle started at that time.

Then, the pixel information signal accumulated in the second shift register SR _b and this second shift register
The pixel information signals of each line corresponding to the image information of the document read by the two-dimensional image sensor IS in the reading period l times after the reading period in which the pixel information signals accumulated in SR _b were obtained are individually to the differentiator DIC
The difference is calculated for each corresponding pixel in , and the difference value for each pixel obtained by the difference device DIC is added for each line in an adder ADD that is reset for each line, and a sum signal S is obtained. _i , but the value of the above addition signal S _i obtained by the adder ADD is
The minimum value is shown in the line where the pixel information signal corresponding to the image information at the position of line A on document 0 is obtained, but the value of the addition signal S _i obtained from the adder ADD mentioned above shows the minimum value. The position of the line on the two-dimensional image sensor IS from which the pixel information signal as shown is obtained is the two-dimensional image sensor IS.
It is clear that the number of lines from a predetermined specific line position varies depending on the sub-scanning speed.

The judgment circuit JC uses an adder ADD for each reading cycle.
Added signal for each line that is output one after another from
It is possible to know at which line from a specific line _{the summed signal S i that} shows the minimum value in S All that is required is to generate an information signal with such bias and magnitude and provide it to the clock controller CCR, which is sequentially transmitted from the adder ADD for each line in each reading period. The numerical values of the output addition signal S _i are compared sequentially, and the time length from the start of each reading cycle until the numerical value changes from a decreasing trend to an increasing trend is counted by counting the number of clock pulses P _f . This can be done using the counted value obtained by counting with a device.

The determination circuit JC as described above can be easily constructed by combining a comparator, a gate, a memory, a counter, and the like. When the sub-scanning speed is faster than the standard sub-scanning speed, the count value of the counter is larger than the standard value, and when the sub-scanning speed is slower than the standard sub-scanning speed, the counter value is larger than the standard value. Since the count value is smaller than the standard value,
The clock controller CCR controls the pulse generator according to the information signal given to it from the judgment circuit JC.
The periods of the pulses P _b , P _c , P _d , and P _e generated by the PSG are changed proportionally at a constant ratio so that changes in the sub-scanning speed are compensated for by changes in the reading period. .

In the embodiment shown in FIG. 5, a subtractor is used as a means for determining the similarity between two pixel information signals.
Although DIC was used, an integrator may be used instead of a subtractor. In this case, the line showing the maximum value among the outputs of the adder for each line is predetermined for the two-dimensional image sensor IS. By knowing the number from the position of a specific line, it generates an information signal indicating the deviation and magnitude of the sub-scanning speed relative to the standard sub-scanning speed. It is sufficient that the determination circuit JC is configured so that it can be applied to the target controller CCR.

By performing the above-described operation for successive reading cycles, in the device of the present invention, even if there is a variation in the sub-scanning speed, the variation in the sub-scanning speed is compensated for by the variation in the reading cycle. Even if the sub-scanning speed changes, a recorded image without image distortion can be obtained in which the recording trace interval (scanning line interval) is kept approximately constant.Therefore, sub-scanning is performed manually. It is a preferred embodiment to apply the present invention to a manual sub-scanning type reader configured as described above.

Note that in a two-dimensional image sensor such as a CCD sensor that converts the amount of light into an amount of charge, it is better to keep the accumulation time _{γ a} constant for better results in subsequent signal processing. Even when the period T is changed, it is desirable that the accumulation time γ _a is kept at a constant value.

As is clear from the above detailed explanation, the device of the present invention effectively utilizes the two-dimensional image sensor, thereby eliminating problems when using two line images S ₁ and S ₂ as in the conventional example. Summer. In addition to solving the problem of difficulty in arranging line image sensors with strict parallelism, it also eliminates the need for large-capacity random access memory that was required in the conventional case, and also eliminates the need for the central processing unit in the conventional case. Compared to a device combined with a random access memory, it is possible to realize faster signal processing and to provide an inexpensive device, and the device of the present invention overcomes the various drawbacks of the conventional device described above. All of these can be successfully resolved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a conventional device, FIG. 2 is a side view of another conventional device, FIG. 3 is a block diagram of an example of the same, and FIG. 4 is a perspective view of a part of the image signal generating device of the present invention. , FIG. 5 is a block diagram of one embodiment of the present invention, and FIGS. 6 a to 6 g are timing charts. IS...Two-dimensional image sensor, SR _a ...First shift register, SR _b ...Second shift register, DIC...Differentiator, ADD...Adder, JC...
Judgment circuit, CCR...clock controller,
PSG...pulse generator, 0...original, 8...imaging optical system.

Claims (1)

[Claims] 1 Photoelectrically converts the two-dimensional image information image of the object to be read formed by the imaging optical system, and generates pixel information signals corresponding to pixel information at a predetermined number of parallel line positions orthogonal to the sub-scanning direction. in a two-dimensional image sensor that can output pixel information signals as a sequence of pixel information signals arranged sequentially on the time axis. Therefore, in order to obtain two-dimensional image information and a corresponding image signal, the object to be read and the two-dimensional image sensor are moved relative to each other. A storage device is provided for storing a pixel information signal obtained at the position of one specific line in the two-dimensional image sensor described above, and the pixel information signal read from the storage device is used as an output image signal. , the pixel information signal read from the storage device described above is detected by the specific one line described above on the two-dimensional image sensor in a reading cycle that is a predetermined number of reading cycles after the reading cycle in which the pixel information signal was obtained. It is used to compare the pixel information signals obtained corresponding to each line position following the position, and further, based on the comparison results, a signal corresponding to the sub-scanning speed is obtained, and thereby the two-dimensional image sensor is An image signal generator that changes the reading cycle.