JPH07212547A - Method and device for inputting picture - Google Patents

Abstract

PURPOSE:To speed up reading and to facilitate the change of the number of picture elements by setting the reading of a CCD linear image sensor to be from a use start picture element to a final picture element to be used, eliminating the rear picture element and setting them to be one scan. CONSTITUTION:The CCD linear image sensor 1 converts the picture obtained by reducing the picture of a subject and image-forming it on a light-receiving surface into charge quantity in accordance with light quantity for the respective picture elements so as to store them. The sensor 1 shifts stored charge quantity for the respective picture elements at every picture element by a driving clock from a controller 3 and a read pulse, and outputs it as CCD output. Counters 4 and 6 decide the use start picture element and the number of use picture elements by a signal outputted by counting the driving clock whose number is designated with DIP switches 5 and 7 and by the read pulse. Namely, the picture elements except for the picture elements are eliminated and they are read as one scan so as to CCD-output them. Thus, reading becomes high speed and the change of the number of the picture elements becomes facile.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to image input such as inspection of printed matter. More specifically, in image input using a CCD linear image sensor as a light receiving sensor, the number of pixels unique to the CCD linear image sensor used is The present invention relates to an image input method and apparatus that can shorten the time for reading a signal from a sensor when the number of pixels required is small and can easily change the number of pixels required for actual use.

[0002]

2. Description of the Related Art Conventionally, as for a CCD image sensor such as a single-plate RGB 3-line type color linear image sensor, currently available products are 2592 bits (pixels).
Type, 5000-bit (pixel) type, 512-bit (pixel) type, 1024-bit (pixel) type, and other products with a small number of bits (pixels) are not sold. Therefore, in designing a linear sensor camera with a small number of bits, it is unavoidable that the 2592-bit sensor is used instead, and only the charge (that is, data) of the bit (pixel) that you want to use is taken in and the remaining bits (pixels) output the charge. The first method used was to throw away after doing. Moreover, separately, Japanese Patent Application No. 61-233
CCD as in 280 (Japanese Patent Laid-Open No. 63-88973)
A second method is also known in which a light-shielding plate is provided on the surface of the image sensor, and not all the pixels of the sensor are used, but it is used as an image sensor with an intermediate bit number, which is not available on the market, to achieve high speed. There is. However, the above-mentioned first method has a problem that a loss time for discharging charges of unused pixels is required, and a time required for reading becomes longer than a reading time for only a few bits. The method of using the second light-shielding plate tried to solve this problem, but once the sensor is installed,
In order to change the number of bits, it is necessary to align the positions of the light shielding plate and the sensor again. There was a drawback that the number of bits could not be changed easily.

[0003]

Under such circumstances, in designing a linear sensor camera, the C
When the number of pixels required for use is smaller than the number of pixels of the CD linear image sensor, one reading cycle (one scan cycle time) can be made shorter and easier than the time required to read all the pixels of the sensor. There has been a demand for a camera image input method and device using a CCD image sensor capable of changing the number of bits used. The present invention is CC
An object of the present invention is to provide an image input method and device which can shorten the cycle time of one scan as much as possible in image input such as inspection of a printed matter using a D linear sensor camera, and can easily change the number of bits used. Is.

[0004]

According to the image input method of the present invention, a CCD linear image sensor is used as a light receiving sensor.
An image input method used for inspection of printed matter, in which the center position of the pixel row to be used is located at the center of the pixel row of the CCD linear image sensor or behind the center, and one pixel of the pixel row of the CCD linear image sensor is used. The reading is started from the eye, the reading is ended at the pixel located at the end of the pixel row to be used, and the reading of the pixels on the rear side of the pixel row to be used is omitted to make one scan. The image input device of the present invention is an image input device that uses a CCD linear image sensor as a light receiving sensor and is used for inspection of printed matter, and starts reading from the first pixel of the pixel line of the CCD linear image sensor. It is provided with a functional unit that finishes the reading at the pixel located at the end of the pixel row and omits the reading of the pixels on the rear side of the used pixel row to make one scan. Specifically, the functional unit includes at least a setting circuit such as a DIP switch for setting the head pixel of a pixel column to be used and a counter, a setting circuit such as a DIP switch for counting the pixel to be used and a counter, and C
It is composed of a CD linear image sensor and a controller which controls in association with the CD linear image sensor. Here, one scan operation from the start of reading charges to the end of reading charges from the CCD linear image sensor is referred to as one scan, and the time required for this one scan is a cycle time (one cycle).
I am trying.

The image input method of the present invention uses the CCD to be used.
Let L be the number of pixels peculiar to the image sensor, M be the number of pixels in a continuous pixel row to be actually used, the first pixel position be the Eth pixel, and the last pixel position be the Fth pixel.
> M, all the pixels from the 1st pixel to the Lth pixel are not sequentially read and set as 1 scan, and 1 scan is made from the 1st pixel to the Fth pixel at the end of the pixel to be used. Reading is omitted for the subsequent (LF) pixels. Then, in such a usage method, in the CCD element, the charges of the (F + 1) th pixel to the Lth pixel are sequentially shifted when reading one scan, as will be described later. Each time after the second scan, from the first pixel,
Since the charges (L−F) after the (F + 1) th pixel are overlapped, at least the pixel row to be actually used is at a position where the charges after the (F + 1) th pixel are not overlapped, that is, (L− It is set after the (F + 1) th pixel. That is, it is necessary to position the center position of the pixel row to be used at the center of the pixel row of the CCD linear image sensor or at the rear side of the center. In this case, it can be understood that one scan becomes shorter as the first pixel position of the continuous pixel row to be actually used is set as close as possible to the (L-F + 1) th pixel. When (L−M) is an even number, the first pixel position of the continuous pixel row to be actually used is (L−F +
It is possible to take one scan at the shortest by taking the 1) th pixel position. At this time, the number of unused pixels on both sides of the pixel column actually used becomes equal to (LF), that is, C
The center of the CD image sensor coincides with the center of the pixel portion actually used. Then, from the relationship of 2 (L−F) + M = L and F− (E−1) = M, the position E of the first pixel of the pixel row actually used is (L−M) / 2 + 1. . Further, when (LM) is an odd number, it is impossible to make the numbers of pixels on both sides of the pixel row actually used to match,
The number of pixels on both sides of the pixel row actually used is (L−F +
1) and (L−F), and the first pixel position of the continuous pixel row to be actually used is set at the (L−F + 2) th pixel position, one scan can be the shortest. At this time, from the relationship of (L−F + 1) + M + (L−F) = L and F− (E−1) = M, the position E of the first pixel of the pixel row actually used is (L−M + 1). / 2 + 1th.

[0006]

With the image input method of the present invention having such a configuration, the time required for the scanning operation (one scan) from the start of reading the charges from the CCD linear image sensor to the end of the reading is made possible for all pixels of the sensor. It is possible to increase the speed as compared with the case of reading out. And
By configuring the image input device of the present invention as described above, the scanning operation (1 scan) from the start to the end of reading the charges from the CCD linear image sensor.
It is supposed that the time required for is faster than that when all the pixels of the sensor are read out, and the number of pixels used can be easily changed. Further, in the image input device of the present invention, specifically, the functional unit sets at least a setting circuit such as a DIP switch for setting the head pixel of the pixel column to be used, a counter, and a DIP switch for counting the pixel to be used. The circuit, the counter, and the controller that controls these in association with the CCD linear image sensor have a simple structure, and the number of pixels to be used can be easily changed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the image input device of the present invention will be described below with reference to the drawings. FIG. 1 shows an example image input device (camera)
FIG. FIG. 2 is an enlarged view of a CCD linear image sensor having 2,592 pixels (bits), and FIG. 3 shows a timing chart for driving the embodiment apparatus. FIG. 4 shows an example using this image input device (camera). FIG. 5 shows the flow of charge shift on the sensor in relation to the timing chart. In FIG. 1, 1 is a CCD linear image sensor, 2 is a lens, 3 is a controller,
4 is a counter, 5 is a DIP switch as a setting circuit,
6 is a counter, and 7 is a DIP switch as a setting circuit. The operation of the image input device (camera) will be briefly described below. In FIG. 1, an image of a subject is formed as a reduced real image on a light receiving surface of a CCD image sensor 1 by a lens 2. The flow of signals will be described with reference to FIG. 5. The formed image is converted into the amount of electric charge on the photoelectric conversion surface, which is the light receiving surface, according to the amount of light, and is stored in the electric charge storage unit. The CCD linear image sensor 1 has a controller 3
A drive clock ((A) in FIG. 3) and a read pulse ((B) in FIG. 3) are given from the pixel, and the charge accumulated according to the light amount for each pixel is CC when the read pulse is input.
The data is transferred to the D transfer unit, and is shifted one by one in the reading direction as shown in FIG. 3 by the driving clock, and is output pixel by pixel. (In FIG. 3C, a negative signal is output according to the amount of light.) The counter 4 is a counter that determines the starting pixel to be used, and counts the drive clock up to the number of pixels designated by the DIP switch 5 (see FIG. D)), take out the carrier (Fig. 3 (E)). The read pulse is used as a signal for presetting and counting start of the counter 4, and when the count up to the preset value is completed, the carrier is output to the unter 6, which serves as a reset and count start signal for the counter 6. The counter 6 is a counter for designating pixels to be used,
The drive clock is counted up to the value designated by the DIP switch 7 (Fig. 3 (F)), and the carrier signal (Fig. 3 (G))
Give out. The carry signal is a signal indicating that the last pixel of the used pixels has been output, and this means that the reading is completed. By inputting the carry signal to the controller 3, the next read pulse can be generated. ,
Move to the transfer cycle of the next row. The signal of the counter 6 is used as a horizontal address. * As for the device,
When the number of peculiar pixels of the CCD sensor to be used is L and the number of pixels of the continuous pixel portion which is actually used is M, by inputting these L and M, the above-mentioned setting to the counter for determining the pixel to be used, The counter for designating the used pixel may be automatically set.

An embodiment of the image input method of the present invention will be described below. An embodiment will be described in which the CCD linear image sensor of 2592 pixels is used in the image input device and signals of 512 pixels are desired. 2 in FIG.
An enlarged view of a CCD linear image sensor having 592 pixels (bits) is shown. In FIG. 2, the 1041st pixel to the 1552th pixel are 512 pixels for which a signal is desired, and one cycle (1 scan from the start of reading to the end of reading) ) From the 1st pixel to the 1552nd pixel instead of from the 1st pixel to the 2592nd pixel,
Readout is omitted from the 1553rd pixel onward. And
Of the 1st to 1552th pixels, only the signals of the 1041st to 1552th pixels are extracted and used. The operation of the CCD linear image sensor is such that the charge stored in each pixel is read out by the photoelectric conversion surface according to the intensity of light (a signal for transferring the stored charge to the charge transfer unit CCD), and the CCD is input. When the next accumulated charge is read without sending out the charge, the charge that has not been sent out is transferred to the CCD.
The next charge will be added while remaining in, and the outputs will overlap. Therefore, this 104
In the case of the present embodiment in which only the 1st pixel to the 1552th pixel is the pixel for which a signal is desired, the 1st pixel to 1040th pixel signals are overlapped on the signal portions of the 1553th pixel to 2592nd pixel that have been transferred without being read out. Thus, the read signal is not used. Since there are no pixels after the 2593th pixel, only the signals corresponding to the charges accumulated in the respective pixels for the 1041st pixel and thereafter are included in the signals read out from the 1st to 1040th pixels. Will be taken out. After all, regarding the 1041st pixel to the 1552th pixel, only the signal corresponding to the charge accumulated in each pixel is extracted. In this example, the cycle time of one scan is 1552/25 as compared with the case of scanning all 2592 pixels.
It is 92, which means that the speed is increased by about 40%.

In the above example, the pixels to be used are the 512 pixels from the 1041st pixel to the 1552th pixel, and the center of this pixel row is the center of the entire 2592 pixel row. However, in some cases, it may be used. The center of the pixel row may be located behind the center of the CCD linear image sensor. However, it is obvious that the cycle time of one scan becomes long.

The embodiment of the image input method of the present invention uses the CCD linear image sensor having the number of 2592 pixels (bits) shown in FIG. 2, uses only 512 pixels, and minimizes the time required for reading. In the case of using the apparatus of the embodiment of the present invention shown in FIG. 1, the necessary pixel rows are changed from the 1041st pixel to the 1552th pixel,
Reads from the 1st pixel to the 1552th pixel,
The dip switch and the counter are set so that the scanning of the 1553rd pixel and thereafter is omitted and one scan is performed.
It is sufficient to set the value of 0 to the value of 512 in the DIP switch 7.

FIG. 4 is a schematic view of a usage example of the image input device (camera) of the embodiment. In FIG. 4, 11 is an imaging camera and 12
Is a data processing unit, 13 is an encoder, 14 is a light source, and 15
Is a printed matter. A camera 11 having a CCD image sensor as a light receiving sensor, a light source (illumination device) 14 for illuminating the traveling printed material 15, an encoder 13 for synchronizing the reading timing of the traveling printed material and the sensor, an encoder 13 and a sensor. It is composed of an image input unit (camera) 11 of a sensor that is associated and controlled, and a data processing unit 12 that processes a signal of the sensor. As described above, the setting of the used pixel can be easily performed by switching with the dip switch, but the preset value of the counter for setting the used pixel is the dip switch as the setting circuit.
Other than the DIP switch, it can be easily set by the controller.

[0012]

With the above arrangement, the image input method of the present invention uses all the pixels of the sensor when the number of pixels (bit number) smaller than that of the CCD linear image sensor is used. The image input device of the present invention is faster than the case of reading, and the image input device of the present invention is faster than the case of reading all the pixels of the sensor, and the number of pixels to be used can be easily changed. I am trying. Further, in the image input device of the present invention, at least the functional unit is provided with a dip switch and a counter for setting the head pixel of the pixel row to be used, a dip switch and counter for the pixel count to be used, and a CCD linear image sensor for these. , And a controller that controls them in association with each other, and the entire device has a simple structure.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an image input device (camera) according to an embodiment of the present invention.

FIG. 2 is a schematic view of a CCD image sensor used in an embodiment of the present invention.

FIG. 3 is a timing chart diagram in the embodiment of the invention.

FIG. 4 is a diagram of a usage example of an image input device for printed matter.

FIG. 5 is a diagram for explaining a charge flow of a CCD linear image sensor.

[Explanation of symbols]

 1 CCD linear image sensor 2 lens 3 controller 4 counter 5 dip switch 6 counter 7 dip switch 11 camera 12 data processor 13 encoder 14 light source 15 printed matter

Claims (3)

[Claims] 1. A method for inputting an image, which is used for inspection of printed matter, wherein a CCD linear image sensor is used as a light receiving sensor, wherein a center position of a pixel row to be used is from a center or a center of the pixel row of the CCD linear image sensor. The pixel is located on the rear side, the reading is started from the first pixel of the pixel row of the CCD linear image sensor, the reading is finished at the pixel located at the end of the pixel row to be used, and the pixel on the rear side of the pixel row to be used is read. An image input method, wherein reading is omitted and one scan is performed. 2. An image input device, which uses a CCD linear image sensor as a light receiving sensor and is used for inspection of printed matter, etc., and which is used by starting reading from the first pixel of the pixel line of the CCD linear image sensor. An image input device comprising a functional unit that finishes reading at the pixel located at the end of the pixel and omits reading of pixels on the rear side of the used pixel column to perform one scan. 3. The setting unit according to claim 2, wherein the functional unit is at least a setting circuit such as a DIP switch for setting a head pixel of a pixel column to be used and a counter, a setting circuit such as a DIP switch for counting a pixel to be used and a counter, And CC these
An image input device comprising a D linear image sensor and a controller for controlling the D linear image sensor.