JP3234650B2 - Red / black data reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a red / black data reading apparatus used for a facsimile reading section or the like.

[0002]

2. Description of the Related Art Conventionally, there is a reading apparatus capable of discriminating and reading white / red / black data on a document. This type of apparatus generally uses a reading method of a reduction optical system using a CCD (solid-state imaging device), and uses a light source of yellow for reading black information and OR information of red information and reading of only black information for yellow information. Red is switched twice for each scan and read twice, black information obtained by scanning with a red light source is used as black data, and the black information is subtracted from black or red information obtained by scanning with a yellow light source to obtain red data. After obtaining the data, one line of read data was completed.

[0003] However, the reading method of the reduction optical system using the CCD described above requires a large space for the optical system, which is extremely disadvantageous for miniaturization of a device generally required. Lens used for
There is a problem that it takes time to adjust the positions of the mirror, the light source, the CCD, the three-dimensional inclination, and the like.

Therefore, a reading device of the same magnification optical system using a contact type image sensor has a CCD inside the sensor.
Similar to the method, a method has been proposed in which light sources of two colors, yellow and red, are read by switching the emission color of the light source every two scans. Can be considerably reduced, and the adjustment of the optical system is hardly required.

FIG. 7 shows a timing chart of image signal output in a reading system using a contact type image sensor. Now, the reading period of the document corresponding to the image signal output V (n, j) of the n-th scan of the j-th pixel of the sensor is from timing t (n-1, j) to t (n, j). T (n, j), during which the j-th pixel receives the reflected light from the document, and the voltage value output by photoelectrically converting the received light amount is V (n, j).
j). Therefore, when the light source switches from yellow to red during the reading period T (n + 1, j) like V (n + 1, j), or V (n + 3, j) If the light source switches from red to yellow during the reading period T (n + 3, j), the output image signal does not necessarily contain the red information accurately or is cut off. Not be used as accurate information. For this reason, the output of the scan immediately after the color of the light source is switched, such as the (n + 1) th scan or the (n + 3) th scan, is not adopted, and red or black information is obtained from the nth scan, and black information is obtained from the (n + 2) th scan. The black information obtained from the (n + 2) th scan is used as black data, and the (n + 2) th scan data is subtracted from the (nth) scan data to obtain red data, thereby completing one line of read data. are doing.

[0006]

However, in the red / black reading apparatus using the contact type image sensor, as shown in FIG. 7, four scans are performed to complete one line of read data. Therefore, there is a problem that the reading time is longer than that of the above-mentioned CCD system. The present invention has been made to solve the above-described problem, and provides a red-black data reading apparatus that can read one line of red-black data by two scans in a reading method using a contact image sensor and can shorten the reading time. The purpose is to do.

[0007]

In order to achieve the above object, according to the present invention, as shown in FIG. 1, a contact type image sensor 10 which photoelectrically converts each read pixel and outputs a read signal is switchable. By scanning one line a plurality of times using the two-color light source 11, white and white in one line are scanned.
In a red-black data reading device that reads and determines red / black data, a light source control unit 12 that switches a light emission color of a light source 11 for each scan, and a light emission color of the light source 11 is switched within a reading period of the contact image sensor 10. Thereby, the image sensor 1 sequentially read and output
When the pixels before and after the change of the binary data of the pixel signal output of 0 are k pixels and k + 1 pixels, the light source control means 1
2, when the light source 11 emits light of one emission color and is scanned, the output of the image sensor 10 up to the k-th pixel is defined as black data, and the data after the (k + 1) -th pixel is defined as black or red data. When the light source 11 emits light of the other emission color and is scanned by the data calculation means 13 and the light source control means 12, the output from the image sensor 10 up to the k-th pixel is set to black or red data, and the k + 1-th and subsequent pixels are output. A second data calculating means 14 for setting the output of the second data to black data;
One line of black data is constituted by the data up to the k-th pixel by the first data operation unit 13 and the data after the (k + 1) -th pixel by the second data operation unit 14,
A data processing unit 15 forming one line of black or red data from the data from the (k + 1) th pixel onward by the first data calculation unit 13 and the data up to the kth pixel by the second data calculation unit 14 It is provided.

[0008]

In the above arrangement, the light source control means switches the light emission color of the light source every scan. The first data calculation means 13 sets the data up to the k-th pixel from the contact type image sensor 10 as black data when scanning with the one light emission color by the light source control means 12, and sets the data after the (k + 1) -th pixel to black or black. Red data. The second data calculation means 14 sets the data up to the k-th pixel from the close contact type image sensor 10 as black or red data when scanning with the other emission color by the light source control means 12, and converts the data after the (k + 1) -th pixel. Assume black data. The data processing means 15 constitutes one line of black data from the data up to the k-th pixel by the first data calculation means 13 and the data from the (k + 1) -th pixel on by the second data calculation means 14. Data from the (k + 1) th pixel onward by the data calculation means 13;
One line of black or red data is formed from the data up to the k-th pixel by the second data calculation means 14.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram showing the electrical configuration of the red / black data reading device. The contact image sensor 10 is configured by 1728 read pixels,
It has a light source 11 driven by a reading control circuit 20 and capable of switching between yellow and red. The amount of light reflected from the original by light from the light source 11 is sequentially determined for each read pixel.
Photoelectric conversion and output. The light source 11 is switched in emission color by a light source switching circuit 21 controlled by a reading control circuit 20, and emits yellow or red light. The image signal output from the contact type image sensor 10 is compared with a predetermined threshold value by a binarization circuit 22, converted into a binarized signal, and sent to a memory 23 and an arithmetic circuit 24.

The output of the contact type image sensor 10 when scanning with the yellow light source is delayed by one scan by the memory 23 and sent to the arithmetic circuit 24, while the output when scanning with the red light source is It is sent directly to the arithmetic circuit 24. Thus, data of the same pixel scanned by each of the yellow and red light sources is input to the arithmetic circuit 24 at the same time. Then, the read data of one line is calculated by the output of the contact type image sensor 10 by two scans, one scan with the yellow light source and one scan with the red light source.

Here, since the emission color of the light source 11 is switched during the pixel reading period by the contact type image sensor 10, even if all the lines are red data, for example,
The binarized data of the pixel signal output for a certain period by the contact image sensor 10 changes at a certain pixel. The pixels before and after this boundary are now referred to as k pixels and k + 1 pixels.

In the arithmetic circuit 24, for the first to k-th pixels, data scanned by the yellow light source one scan before obtained from the memory 23 is set as black data and obtained from the binarization circuit 22. The data scanned by the red light source is set as black or red data, and the red data is calculated by subtracting the black data from the memory 23 from the black or red data obtained from the binarization circuit 22.

For pixels from the (k + 1) th pixel to the 1728th pixel, data scanned by the yellow light source one scan before obtained from the memory 23 is converted into black or red data.
Using the data scanned by the red light source obtained from the binarization circuit 22 as black data, the black data obtained from the binarization circuit 22 is subtracted from the black or red data from the memory 23 to calculate red data. I do.

FIG. 3 shows an example of output from the contact image sensor 10 and an example of binarization in the binarization circuit 22. The upper part of FIG. 3 shows a case where the light source 11 emits yellow light, and the original is white,
This is an example of the scanning output of the contact image sensor 10 in the case of black, where a indicates white reading, b indicates red reading, and c indicates black reading. The lower diagram shows a scanning output example of the contact image sensor 10 when the light source 11 emits red light and the original is white, red, and black, where d is white reading, e is red reading, and f is black. Indicates when reading.

As can be seen from FIG. 1, when the original is white or black, the output is the same whether the light source 11 is yellow or red. When the original is red, the output is the same as when the original is black when the light source 11 is yellow. When the light source 11 is red, the output is the same as when the original is white. VTH indicates a threshold value to be binarized by the binarization circuit 22 with respect to each of the above output examples. An output larger than the threshold value is determined as "0", and an output smaller than the threshold value is determined as "1". Therefore, in the above output example, a =
It is determined that 0, b = 1, c = 1, d = 0, e = 0, and f = 1.

FIG. 4 is a timing chart showing the timing at which the output of the contact image sensor 10 and the light source 11 are switched. In reading the M-th line (M is an arbitrary integer), the (n-1) th scan (n is an arbitrary integer) and the n-th scan are performed. The data of the (n-1) th scan binarized by the binarization circuit 22 is delayed by one scan in the memory 23 and sent to the arithmetic circuit 24, and the data of the nth scan is directly sent to the arithmetic circuit 24. Sent to

The output V (n, k) of the k-th pixel in the n-th scan
Is a period T (n, k) from timing t (n-1, k) to t (n, k).
The k-th pixel receives the reflected light from the document, and indicates the voltage value output by photoelectrically converting the received light amount.
The light source switches from yellow to red at the timing tLn, and switches from red to yellow at the timing tLn + 1.

FIG. 5 shows output examples for the 1st, k, k + 1, and 1728th pixels of the n-th scan when the original is red and the light source is red. V (n, 1), V (n, k), V (n, k + 1), V (n, 172
8). V (n, 1) is the light receiving period T (n,
Since all the light sources in 1) are yellow before switching to red, the output level is the same as black. On the other hand, V (n, 1728)
Since all light sources in the light receiving period T (n, 1728) are red, the output level is the same as that of white. However, V (n, K)
And V (n, K + 1) are the light receiving periods T (n, K) or T (n, K +
In 1), the light source switches from yellow to red, so it floats at an intermediate level. At this time, V (n, K) falls below the threshold value VTH, so that the binarization result is determined to be black. V (n, K + 1) exceeds the threshold value VTH, so that the binarization result Is determined to be white.

That is, at the n-th scan, when the red of the original is read, the first to k-th pixels are binarized as "1". What is binarized as “1” is black or red data. Also, 17 from the (k + 1) th pixel
Up to the 28th pixel is binarized as “0”. That is,
At this time, only the black data is binarized as “1”.

FIG. 6 shows the first, k, k + 1, and 1st scans of the (n-1) th scan when the original is red and the light source is yellow, as in FIG.
Output examples for the 728th pixel are V (n-1,1) and V (n-
1, k), V (n-1, k + 1) and V (n-1,1728).
That is, in the (n-1) th scan, when the red of the document is read, contrary to the nth scan, the first to kth pixels are binarized as “0”, and thus “1”. Only the black data is binarized by
Since up to the 28th pixel is binarized as “1”,
What is binarized as “1” is black or red data.

From the above, as the read data of the M-th line, from the first pixel to the k-th pixel, black data is obtained from the data of the (n-1) th scan, and black or red data is obtained from the data of the nth scan. Therefore, red data can be obtained by subtracting the data of the (n-1) th scan from the data of the nth scan. In addition, from the (k + 1) th pixel to the 1728th pixel, black data is obtained from the data of the nth scan, and
-1 Since black or red data is obtained from the data of the first scan,
By subtracting the data of the n-th scan from the data of the (n-1) -th scan, red data can be obtained.

As is apparent from the above operation example, in the red-black data reading apparatus of the present invention, it is only necessary to perform two scans to obtain one line of data using the contact image sensor. The time required can be shortened. Further, the present invention is not limited to the configuration of the embodiment described above, and various modifications are possible. For example, pixels k and k + 1 before and after the binary data of the pixel signal output of the contact type image sensor change, and a threshold value. The relationship with the value may be set as appropriate.

[0023]

As is apparent from the above description, according to the present invention, it is necessary to use a contact type image sensor and a switchable two-color light source to read one line of red-black data twice. Only scanning is required, the time required for reading can be reduced, the reading process can be speeded up, and the size of the apparatus can be reduced as compared with the case where a CCD is used.

[Brief description of the drawings]

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

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

FIG. 3 is a diagram illustrating an output example of a contact image sensor according to an embodiment of the present invention.

FIG. 4 is a timing chart showing an operation example of one embodiment of the present invention.

FIG. 5 is a diagram illustrating an output example of a contact image sensor according to an embodiment of the present invention.

FIG. 6 is a diagram illustrating an output example of a contact image sensor according to an embodiment of the present invention.

FIG. 7 is a timing chart showing an operation example of the related art.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 contact image sensor 11 two-color light source 12 light source control means 13 first data calculation means 14 second data calculation means 15 data processing means

Claims (1)

(57) [Claims] 1. A line is scanned a plurality of times by using a contact type image sensor that photoelectrically converts each read pixel and outputs a read signal, and a switchable two-color light source, thereby scanning one line a plurality of times. In a red-black data reading device that reads and determines white / red / black data, a light source control unit that switches a light-emitting color of a light source for each scan, and that a light-emitting color of the light source is switched within a reading period of the contact image sensor. In the case where the pixels before and after the binary data of the pixel signal output of the image sensor sequentially read and output are changed are k pixels and k + 1 pixels,
When scanning is performed by causing the light source to emit light of one emission color by the light source control means, the output of the image sensor up to the k-th pixel is set to black data, and the data after the (k + 1) -th pixel is set to black or red data. When the light source controls the light source to emit light of the other emission color and scans, the output up to the k-th pixel from the image sensor is set to black or red data, and the output after the (k + 1) -th pixel is output. A second line of black data from the second data calculation unit as black data, the data up to the k-th pixel by the first data calculation unit, and the data after the (k + 1) -th pixel by the second data calculation unit Comprising the first
Data from the (k + 1) th pixel onward by the data calculation means of
A data processing unit for forming one line of black or red data from the data up to the k-th pixel by the second data calculation unit.