JPH01174162A - Picture input device - Google Patents

Abstract

PURPOSE:To attain read output of a picture at a required area by catching a shadow of an original formed in the visual field of an image sensor by the image sensor, obtaining information of original size and extracting the picture based on the information. CONSTITUTION:At first an original is fed by a motor 7 and a tip of the original is stopped at the read position of the image sensor 3. When the original is lighted by the light source 2, the shadow of the tip of the original is formed in the visual field of the sensor 3 and the black part is extracted from the picture signal of the shadow read by the sensor 3 at a comparator 5. Then an original size detection circuit 9 detects the width of the original based on the black part. Then the original carrying by the motor 7 is started again. The data obtained by the sensor 3 is binarized by the comparator 5 and given to a FF 10. The data of the region at the outside of the said original width is erased from the FF 10 by the control of the control circuit 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a document moving type image input device that detects the document size.

(Prior art) In an image input device that reads an image from a document to obtain image data, the document is fed in one direction while the line
It is read by an image sensor and converted into image data. Such devices can process multi-column-sized originals, but when processing small-sized originals, it is recommended to use the full-size line image sensor in the same way as when processing large-sized originals. In this case, all the areas that protrude from the original are generated as useless image data, so the image reading is performed by detecting the original size and blanking out the image data in areas other than the necessary areas.

The configuration of an image input device having such a document size detection function is shown in FIGS. 6 and 7. FIG. 6 is a block diagram showing the circuit configuration of a conventional device, FIG. 7(a) is a side view showing the main structure, and FIG. 7(b) is a plan view thereof. In FIG. 6, 1 is the main body of the image input device;
5 is a host system to which this main body l is connected.
2 is a light source, 3 is an image sensor, and 4 is a sensor driver that controls this image sensor 3. 5 is a comparator, and 6 is a slice level circuit that sets a threshold value of a signal to be extracted in order to binarize the image signal. Compare the outputs and mark the output exceeding the standard value (threshold) as "1", and the output below as rOJ.
This is given to the flip-flop IO as pixel data. Reference numeral 7 denotes a stepping motor that sends out the original, 8 a motor drive circuit that drives and controls the stepping motor 7, 11 a control circuit, 12 an input/output interface for the host system 15, 13 a control panel, and 29.47 to 49 paper sensors. It is. A control circuit 11 is in charge of overall control.

As shown in FIG. 7, the mechanical part of the image input device is a guide plate
The paper 16 guided by the paper 16 is held between a pair of rollers 18 and 19, and one of the rollers 18 and 19 is driven to rotate by the stepping motor 7, thereby feeding the paper 16.

The paper 1G sent out by the rollers 18 and 19 is guided by the guide plate 20 and sent to the image sensor 3 position, and the portion that reaches the image sensor 3 position is read by the image sensor 3, and the image is It becomes a corresponding signal. The dotted line indicated by the reference numeral 25 becomes the reading line of the image sensor 3. A light source 2 that illuminates the reading surface of the original is located at the image sensor 3, and the original is illuminated with light 23 from the light source 2. The exit side of the rollers 18 and 19 has B3°B2. Vapor sensors (charged detection elements) 29.48 to 49 are arranged to optically detect the presence or absence of paper at the edge corresponding position corresponding to standard paper sizes such as AI, A2, etc. When the document is sent out with its edges aligned, the paper size of the document 16 can be determined by which vapor sensor is detecting the paper. The scanned original 16 is sandwiched between a pair of rollers 27 and 28 and then discharged.

In such a configuration, when the user sets the original 16 in a predetermined position and commands reading by operating the control panel 13, the control circuit 11 receives this and clears the flip-flop 10, turning on the light source 2 and so on. Control of the sensor driver circuit 4 and motor drive circuit 8 is started. Then, the motor drive circuit 8 controls the rotation of the motor 7 to drive the rollers 1g and 19 and the roller 27.2g.
Rotate. Therefore, the leading edge of the set document 16 is held between the rollers 18 and 19 and conveyed. In this way, the original 1G is sent to the positions of the paper sensors 29.47-749, but the original 16 is sent to the positions of the paper sensors 29.47-49.
When the document 16 has been conveyed enough times to reach the position , the control circuit 11 controls the motor to stop so as to temporarily stop feeding the document 16 . The control circuit 11 then checks the outputs of the vapor sensors 29, 47 to 49, and recognizes the paper size from these detection signals. After that, the control circuit 11 starts transporting the document 16 again, and when it reaches the position of the image sensor 3, the image data read by the image sensor 3 is sequentially converted into a clock signal for each pixel of the image sensor under the control of the sensor driver circuit 4. This data is taken out synchronously and compared with the slice level by the comparator 5, and the output exceeding the slice level is given to the flip-flop 10 as pixel data. As a result, the 1st number smaller than the slice level is “0
”, and anything beyond that becomes “]”, allowing for binarization.

Since the control circuit 11 recognizes the paper size, it applies a blank signal to the clear terminal CLR of the flip-flop IO during the period when the signal for the region of the pixel data outside the paper size of the original 16 is output from the flip-flop 10. Stop the signal. As a result, the flip-flop 10 can provide the read image signal to the interface circuit 12 in a form in which the image signal of the area outside the paper size of the original 16 is erased, and the signal of the read image of the original 16 can be transmitted through the interface circuit 12. The image signals within can be given to the host computer 15.

[Problems to be Solved by the Invention] As described above, the conventional image input device has a paper sensor installed at a specific position corresponding to each paper size on the document conveyance path.
Before reading the document, the document is temporarily stopped at the paper sensor position, and the paper sensor's detection output is captured.
The paper size is recognized, the paper is then conveyed to the image sensor position, and the image signal read and output by the image sensor is controlled so that the area outside the paper size of the document is blanked, and the image signal corresponding to the document portion is controlled to be blank. I tried to extract the image signal.

Therefore, it is necessary to prepare a paper sensor for each paper size, and installation space is limited.
At most, paper sensors can only be provided to correspond to a fixed size.

However, since documents do not always have such a fixed size, when a paper sensor is installed to detect the fixed size as described above, the following error occurs.

For example, if a paper sensor is installed to detect standard sizes A and B, an A2 size document will fall within the reading ranges C and D as shown in Figure 5, but B3
A document that is intermediate in size between A2 and A2, and that partially covers the A2 size paper sensor, will be determined to be A2 size, and the image signal of the area that extends beyond the width of the document, even though it is smaller than A2 size, will be detected. will also be extracted. On the other hand, if the size is determined to be 83,
Since only image signals of areas corresponding to three sizes are extracted, the image of the original document will be missing. Therefore,
This is inconvenient when processing non-standard-sized originals.

Therefore, an object of the present invention is to be able to read an image in an area equivalent to the width of a set original, and to be able to read and output an image in a necessary area even if the original is a non-standard size. An object of the present invention is to provide an image input device that achieves the following.

[Means for Solving the Problems] In order to achieve the above object, the present invention is configured as follows. In other words, in an image input device that uses an image sensor having a readable document width and sequentially reads and outputs image data with the image sensor placed at a fixed position while conveying the document by a conveyance mechanism, the image sensor is A driver circuit that controls reading, an image data output control means that is provided on the output side of the image sensor and that blanks the output of the image sensor using a blank signal, and a light source that illuminates the field of view of the image sensor obliquely from the document feeding direction. Then, the document transport mechanism is controlled to be driven until the leading edge of the set document reaches a position where a shadow is formed by the illumination in the visual field of the image sensor, and when the document reaches the position, the document feed is stopped and the driver The circuit is controlled to control the reading of the image sensor and execute the document size detection control, and when the document size information is obtained, drive control of the document transport mechanism and reading control of the image sensor are started, and the image data output control means is controlled. is a control circuit that controls to give a blank signal during the output period of the image sensor outside the reading area corresponding to document size information, and a control circuit that controls the shadow distribution based on the output of the image sensor when the control circuit performs document size detection control. The document size detection circuit extracts the area and supplies this information to the control circuit as document size information.

[Function] In this device, when a document is set, the control circuit controls the transport mechanism to drive until the leading edge of the set document reaches a position where a shadow is formed by the illumination in the field of view of the image sensor. . Then, when the document reaches the position, feeding is stopped, and the driver circuit is controlled to perform reading control of the image sensor, and document size detection control is executed. Thereby, the document size detection circuit extracts the shadow distribution area based on the output of the image sensor at this time, and provides this information to the control circuit as document size information. Upon obtaining the document size information, the control circuit starts drive control of the transport mechanism and reading control of the image sensor, and blanks the image data output control means when outputting image data in a period outside the document size output from the image sensor. to be carried out.

As a result, the image data during the period outside the original size becomes blank, and image data of only the necessary area can be obtained. In this way, the original is sent to the field of view of the image sensor, the feeding of the original is temporarily stopped, and the shadow of the original is formed in the field of view of the image sensor by the illumination light from the light source that illuminates the field of view of the image sensor from an angle. The shadow image is captured by an image sensor to obtain document size information, and the image extraction area is known from the obtained document size information and the image within the area is extracted. According to the present invention, there is provided an image input device that can read an image in an area equivalent to the width of a set original, and can read and output an image in a necessary area even if the original is of a non-standard size. I can provide it.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the circuit configuration of this device, FIG. 2(a) is a side view showing the main structure, and FIG.
) is its plan view.

In the figure, 1 is a main body of an image input device, and 15 is a host system to which this main body 1 is connected.

2 is a light source, 3 is an image sensor having a configuration in which a plurality of imaging elements are arranged in parallel, and 4 is a sensor driver that sequentially scans each imaging element of this image sensor 3 and controls readout of a signal of each pixel. 5 is a comparator; 6 is a slice level circuit that sets a threshold value of a signal to be extracted for data binarization; the comparator 5 adjusts the output of the image sensor 3 based on the set value of the slice level circuit 6 The pixel data of the binarized signal is given to the flip-flop IO as pixel data of a binarized signal, in which the value exceeding the reference value is set to "1", and the value below it is set to "0". 7 is a stepping motor that sends out the original, 8 is a motor drive circuit that drives and controls this stepping motor 7, 11 is a control circuit, and 12 is a host system 1.
5 is a human/output interface, 13 is a control panel, and 29 is a paper sensor. A control circuit 11 is in charge of overall control. Reference numeral 9 denotes a document size detection circuit that detects the document size based on the pixel data output from the comparator 5, and is controlled by the control circuit 11 to detect the document size at the initial stage of reading the document and send the information to the control circuit 11. It is given to

As shown in FIG. 2, the 8 mechanical parts of the image input device move the paper 16 guided by the guide plate 17 to a pair of rollers 1g.

While holding the rollers 1g and 19 in place, one of the rollers 1g and 19 is rotated by a stepping motor 7 to feed the rollers 1g and 19.

The paper 16 sent out by the rollers 18 and 19 is guided by the guide plate 20 and sent to the image sensor 3 position, and the portion that reaches the image sensor 3 position is read by the image sensor 3, and the image is It becomes a corresponding signal. The dotted line indicated by reference numeral 25 is the reading line of the image sensor 3. At the position of the image sensor 3, there is a light source 2 that illuminates the reading surface of the original from diagonally above in the transport direction of the original, and the original is illuminated with light 23 from the light source 2.

On the exit side of the rollers 18 and 19, only a paper sensor (photoelectric detection element) 29 for optically detecting the presence of the paper is provided on the side of the document placement standard guide 30, which was previously required. B3. The paper sensor at the standard paper size position such as B2°Al, A2, etc. is missing. When the edge of the original is aligned with the original setting reference guide 30 and the original is sent out, the paper sensor detects the paper, and this signal causes the control circuit 11 to move the motor 7 to the leading edge of the original 1G or the reading line position of the image sensor 3. The paper is fed by a predetermined amount (the drive is controlled, the paper is stopped at this point, and the light from the light source 2 that irradiates light from diagonally above is used to actively form a shadow on the manuscript paper, and the image sensor 3 reads the shadow). The paper size of the original 16 is determined from this read data.The read original 16 is sandwiched between a pair of rollers 27.2g and ejected.

In such a configuration, when the user sets the document 1G at a predetermined position based on the installation standard guide 30 and commands reading by operating the control panel 13, the control circuit 11 receives this and outputs the flip-flop 1.
0 is cleared, and lighting of the light source 2 and control of the sensor driver circuit 4 and motor drive circuit 8 are started. The motor drive circuit 8 then controls the rotation of the motor 7 to drive the roller 1.
g, 19 and rollers 27, 28. Therefore, the leading edge of the set document 16 is held between the rollers 1g and 19 and conveyed. In this way, the original 1G is sent to the position of the vapor sensor 29. When the original 16 is detected by the paper sensor 29, the control circuit 11 uses the detection output to manage the amount of original feeding using the built-in timer function, and When the document 1B is transported by the amount that reaches the reading position of the image sensor 3 (slightly in front of the optical axis of the image sensor 3), the feeding of the document 1B is temporarily stopped! The motor is controlled to stop so as to cause the motor to stop.

The light source 2 is composed of an LED array, and is designed to illuminate the field of view of the image sensor 3 from diagonally above in front of the image sensor 3, which is arranged in the same manner over the maximum document width. Therefore, a shadow 2G of the leading edge of the document 16 is formed in the field of view of the image sensor 3. The image sensor 3 is constructed by linearly arranging minute imaging elements over the maximum document width, and each imaging element constitutes a pixel. The image data No. 26 faithfully reflects the paper width of the original 1B. The image signal of the type 2B read by the image sensor 3 is compared with the slice level by the comparator 5, and a portion determined to be black is extracted, and is provided to the document size detection circuit 9 under the control of the control circuit 11.

The document size detection circuit 9 has a configuration as shown in FIG.
Start signal 31 (scanning of image sensor 1
The 16-frequency division counter 35 and the 10-bit counter 36 are cleared by the clock signal 32 (synchronized every cycle), and are caused to count by the image sensor readout clock signal 32 (FIG. 4(b)). Further, the clock signal 32 is provided as an operating clock for the D flip-flops 38 and 39. Pixel signal 33 (fourth
Figure (C)) shows 2 at the slice level by comparator 5.
It is converted into a value, where "0" is black and "1" is white. The D flip-flop 38 operates in synchronization with the 6-switch signal using this binary signal as D terminal data, and when the data becomes white, that is, "1", the Q terminal is set to "1". On the other hand, the D flip-flop 39 operates in synchronization with the clock signal, and sets the Q terminal to "1" when the data in the D flip-flop 38 becomes "1". Since the operations of these D flip-flops 38 and 39 are shifted by one clock, the difference between the two, that is, the logical differentiation, can be obtained by passing the output through the exclusive OR circuit 40 of these D flip-flops 38 and 39 (Fig. 4). (d)) A signal corresponding to the width of the document 1B and the timing of the maximum reading position of the image sensor 3 can be obtained. This exclusive OR circuit 4
The left margin (
xi) Left margin signal 34 giving the scanning period of the position in FIG.
When the output of the exclusive OR circuit 40 is gated in (FIG. 4(e)), a signal corresponding to the scanning timing at the right end position of the document 16 is obtained as shown in FIG. 4(r), so this is It is provided as a clock signal for the bit flip-flop 37. The 10-bit flip-flop 37 converts the count value of the 10-bit counter 3B into this clock signal (fourth clock signal).
(FIG. (f)), and the O bit counter 3G receives the 16 frequency divided output of the 16 frequency dividing circuit 35 for one scan period of the image sensor 3 (one cycle of sequentially reading out and scanning the imaging elements from the left end to the right end). The counter 3 counts at the moment when the shadow at the right edge of the document disappears during one scanning period of the image sensor 3.
The flip-flop 37 will take in the value of 6. This captured value is held until the start of the next scanning cycle of the image sensor 3. Here, the resolution of the image sensor 3 is 16 dat/mn+. Therefore, by counting the output divided by 16, it is possible to detect the width of the document in milliliter units.

When the width of the document 16 is detected in this manner, the control circuit 11 recognizes the paper size of the document based on this detection data. After that, the control circuit 11 again controls the document 1.
6, the elements of the image sensor 3 are sequentially scanned from left to right under the control of the sensor driver circuit 4, and the images of the document 16 captured by the image sensor 3 are sequentially taken out in synchronization with the clock signal. . This data is compared with the slice level by comparator 5 and 21if! This is processed as pixel data by the flip-flop 10.
given to. Since the control circuit 11 recognizes the paper size, it applies a blank signal to the clear terminal CLR of the flip-flop IO during the period when the signal of the area of the pixel data is outside the paper size of the original 16.
The output signal of the flip-flop 10 is set to "0". As a result, the image data signal of the read pixels can be supplied from the flip-flop IO to the interface circuit 12 in a form in which the image signal of the area outside the paper size of the original 16 is erased, and the image data signal of the original 1B can be supplied to the interface circuit 12 via the interface circuit 12. Image data within the reading range can be provided to the host computer 15.

In this way, in an image input device that uses an image sensor having a readable document width and sequentially outputs image data read pixel by pixel by the image sensor placed at a fixed position while conveying the document by a conveyance mechanism, the image sensor a driver circuit that controls the reading of the image sensor; an image data output control means that is provided on the output side of the image sensor and that blanks the output of the image sensor by a blank signal; The light source and the original transport mechanism are controlled to be driven until the leading edge of the original that has been set and sorted reaches a position where a shadow is formed by the illumination in the field of view of the image sensor, and when the leading edge of the original is reached, the feeding is stopped. , controls the dry drive circuit to control reading of the image sensor and executes document size detection control, and when document size information is obtained, starts drive control of the document transport mechanism and reading control of the image sensor, and reads the image data. The output control means includes a control circuit that controls to give a blank signal during the output period of the image sensor when the image sensor is out of the reading area corresponding to the document size information, and a control circuit that controls the output of the image sensor to provide a blank signal when the control circuit executes the document size detection control. The apparatus further includes a document size detection circuit which extracts the shadow distribution area and supplies this information as document size information to a control and roll circuit. Then, when the original is set, the control circuit controls the transport mechanism to drive until the leading edge of the original that has been set reaches a position where a shadow is formed by the illumination in the field of view of the image sensor. Then, when the document reaches the position, feeding is stopped, and the driver circuit is controlled to perform reading control of the image sensor and execute document size detection control. Thereby, the document size detection circuit extracts the shadow distribution area based on the output of the image sensor at this time, and provides this information to the control circuit as document size information. Upon obtaining the document size information, the control circuit starts drive control of the transport mechanism and reading control of the image sensor, and blanks the image data output control means when outputting image data in a period outside the document size output from the image sensor. to be carried out. As a result, the image data during the period outside the original size becomes blank, and image data of only the necessary area can be obtained.

Therefore, according to the present invention, it is possible to read an image in an area equivalent to the width of the set original, and even in a non-standard-sized original, image information in a necessary area can be read and output. , it is possible to obtain the effect that there is no need to take the trouble to provide a paper sensor for detecting the paper size.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with appropriate modifications within the scope of the gist thereof.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to read an image in an area equivalent to the width of a set document, and even in a non-standard-sized document, it is possible to read an image in a necessary area. It is possible to provide an image input device that can output images.

[Brief explanation of the drawing]

FIG. 1 is a circuit configuration block diagram showing an embodiment of the present invention.
Fig. 2 is a side view showing the structure of the main parts of this device. Fig. 6 is a block diagram showing the circuit configuration of the conventional device. Fig. 7 is a side view showing the structure of the main parts. and a plan view. 2... Light source, 3... Image sensor, 4... Sensor driver circuit, 5... Comparator, 6... Slice level circuit, 7... Step motor, 8... Motor drive circuit, 9... Original size detection circuit, 10...
・Flip-flop, 11...control circuit, +
3...Control panel, 29...Paper sensor, 16...Document. Applicant's agent Patent attorney Takehiko Suzue Figure 3 (b) CL and Ichijiri plate No. 5 Ward Figure 7

Claims (1)

[Claims] In an image input device that uses an image sensor having a readable document width and sequentially outputs image data read pixel by pixel by the image sensor placed at a fixed position while conveying the document by a conveyance mechanism, the image sensor is read in pixel by pixel. A driver circuit that controls reading, an image data output control means that is provided on the output side of the image sensor and blanks the output of the image sensor using a blank signal, and a light source that illuminates the field of view of the image sensor obliquely from the document feeding direction. Then, the document transport mechanism is controlled to be driven until the leading edge of the set document reaches a position where a shadow is formed by the illumination in the visual field of the image sensor, and when the document reaches the position, the document feed is stopped and the driver The circuit is controlled to control the reading of the image sensor and execute the document size detection control, and when the document size information is obtained, drive control of the document transport mechanism and reading control of the image sensor are started, and the image data output control means is controlled. is a control circuit that controls to give a blank signal during the output period of the image sensor outside the reading area corresponding to document size information, and a control circuit that controls the shadow distribution based on the output of the image sensor when the control circuit performs document size detection control. An image input device comprising: a document size detection circuit that extracts a region and provides this information as document size information to a control circuit.