JP2021125774A - Reading device - Google Patents

Abstract

To provide a reading device capable of obtaining more excellent reading result than conventional one.SOLUTION: In a forward path where a CIS unit is moved from an original position to a forward path reading termination position, pixel data in each line, extended in a main scanning direction is acquired, and then the presence/absence of a bracing candidate line in which data of a plurality of black levels continuously appears in the main scanning direction is determined (S6). When there is the bracing candidate line, the pixel data of the predetermined number of lines, containing the bracing candidate line is acquired in a return path where the CIS unit 6 returns from the forward path reading termination position to the original position, and it is confirmed on the basis of its pixel data whether or not the data of the plurality of black level continuously appears in the amin scanning direction in the pixel data of the bracing candidate line (S7). When confirming that the data of the plurality of black level does not continuously appear in the main scanning direction, the pixel data of the bracing candidate line acquired in the forward path is replaced to the pixel data of the bracing candidate line acquired in the return path (S9).SELECTED DRAWING: Figure 5

Description

The present invention relates to a reader.

In a scanning device capable of reading a document by the FB (Flat Bed) method, a scanning unit that reads one line along the main scanning direction is provided under the transparent platen so that it can be moved in the sub-scanning direction. Has been done. While the scanning unit is moved in the sub-scanning direction, the documents placed on the platen are read line by line by the scanning unit.

The reading unit includes a light source, a rod lens array, and a light receiving unit. Light is emitted from the light source to the document on the platen, and the light reflected by the document is imaged on the light receiving unit (image sensor) through the rod lens array. The light receiving unit includes a plurality of sensor IC chips arranged in the main scanning direction, and each sensor IC chip includes a large number of photoelectric conversion elements arranged in the main scanning direction. Each photoelectric conversion element corresponds to a pixel, and the pixel corresponding to the photoelectric conversion element arranged at the end on one side of the main scanning direction in the sensor IC chip at the end on one side in the main scanning direction is the first pixel, and is the main pixel. The final pixel is the pixel corresponding to the photoelectric conversion element arranged at the end of the sensor IC chip on the other side of the scanning direction and on the other side of the main scanning direction. One line is a pixel group composed of each pixel from the first pixel to the last pixel. In reading one line, the reading unit sequentially outputs pixel data (pixel values) according to the amount of light received by the photoelectric conversion element for each pixel from the first pixel to the last pixel.

If noise is mixed in the reading unit during the output of pixel data for one line, the pixel data output from the sensor IC chip becomes black level data after the time of mixing, and the image related to the image data obtained by scanning the original. Black streaks may occur along the main scanning direction. When black streaks occur, it is desirable to determine whether the black streaks are due to the black streaks present in the document or due to noise mixing, and take measures according to the result of the determination. ..

Therefore, a photoelectric conversion element that constantly outputs a white level signal during reading of one line is provided in the reading unit, and when a black level signal is output from the photoelectric conversion element, noise is mixed in the reading unit. A technique for determining and replacing the line with the pixel data of the previous line has been proposed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 10-257274

However, replacement with data from another line can result in poor read results.

An object of the present invention is to provide a reading device capable of obtaining better reading results.

In order to achieve the above object, the reading device according to the present invention has an image sensor in which a plurality of photoelectric conversion elements are arranged in the main scanning direction, and the reading unit for reading a document and the reading unit are orthogonal to the main scanning direction. A moving mechanism for moving the data in the sub-scanning direction and a control unit are provided. The outbound reading process for acquiring the pixel data of each line extending in the main scanning direction by reading the data, and determining whether or not each pixel data output from the image sensor by the outbound reading process is black level data, and a plurality of data. When it is determined that there is a streak candidate line in the presence / absence determination process for determining the presence / absence of the streak candidate line in which black level data appears continuously in the main scanning direction and the presence / absence determination process, the reading unit uses the moving mechanism to determine the reading end position. In the return path, which is moved from to to the other side in the sub-scanning direction, the original is read and pixel data is acquired from the image sensor, and a plurality of black level data appear continuously in the main scanning direction in the pixel data of the streak candidate line. If it is determined that there is no muscle candidate line in the muscle confirmation process and the presence / absence judgment process to determine whether or not it is present, or if it is determined that it will appear in the muscle confirmation process, the pixel data of each line in the outbound reading process is output as it is. When it is determined by the non-replacement output processing and the streak confirmation processing that multiple black level data do not appear consecutively in the main scanning direction, among the pixel data of each line in the outbound reading processing, the streak candidate line pixel The data is output by replacing the pixel data of the muscle candidate line acquired during or after the muscle confirmation process, and the pixel data of each line other than the muscle candidate line is output as it is in the outward reading process. To execute.

According to this configuration, the pixel data of each line extending in the main scanning direction is output from the image sensor on the outward path in which the reading unit is moved from the reading start position to the reading end position in the sub-scanning direction. The control unit determines whether or not each pixel data output from the image sensor is black level data, and whether or not there is a streak candidate line in which a plurality of black level data continuously appear in the main scanning direction. Is judged. When there is a streak candidate line, a plurality of black level data are added to the pixel data of the streak candidate line based on the pixel data output from the image sensor on the return path in which the reading unit returns from the reading end position to the reading start position. It is confirmed whether or not the data appear continuously in the main scanning direction.

Then, when a plurality of black level data appear continuously in the main scanning direction in the pixel data of the streak candidate line, the control unit receives the pixel data of each line acquired from the image sensor when the reading unit moves in the outward path. Is output. Further, even when there is no muscle candidate line, the control unit outputs the pixel data of each line acquired from the image sensor when the reading unit moves on the outward path.

On the other hand, although there is a streak candidate line, control is performed when a plurality of black level data do not appear consecutively in the main scanning direction in the pixel data of the streak candidate line output from the image sensor when the return path of the reading unit is moved. The unit acquires the pixel data of each line acquired from the image sensor when the reading unit moves on the outward path, and the pixel data of the muscle candidate line from the image sensor when the reading unit moves on the returning route. It is replaced with pixel data and output.

Therefore, a better reading result can be obtained as compared with a configuration in which the pixel data of the streak candidate line is replaced with the pixel data of another line and output.

According to the present invention, better reading results can be obtained than before.

It is sectional drawing of the reading apparatus which concerns on one Embodiment of this invention. It is a top view of the housing of a reading device. It is a top view of the reading part. It is a block diagram which shows the electrical structure of a reader. It is a flowchart which shows the flow of a reading process. It is a top view for demonstrating the outward reading. An example of pixel data acquired in the outward reading is shown graphically, and the relationship between the black reference data and the threshold value is shown. It is a flowchart which shows the flow of the line confirmation process. It is a top view for demonstrating the return reading. It is a figure for demonstrating the emission color at the time of the outbound reading. It is a figure for demonstrating the emission color at the time of return reading.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Structure of reader>
The reading device 1 shown in FIG. 1 is a device capable of reading a document by an FB (Flatbed) method. The reading device 1 includes a housing 2 and a cover 3. The housing 2 has a substantially rectangular parallelepiped shape. The cover 3 is supported by the housing 2 and is provided so as to be swingable around an axis extending along one side edge of the upper surface of the housing 2. Due to the swing of the cover 3, the side opposite to the swing axis side is lifted with respect to the upper surface of the housing 2 to open the upper surface of the housing 2, and the cover 3 is laid down with respect to the upper surface of the housing 2. It is displaced so that the upper surface of 2 is closed.

In the reading device 1, the lifting side of the cover 3 is the front side. The front-back, left-right directions used in the following description are defined based on the state in which the reading device 1 is viewed from the front side. In FIG. 1, the upper, lower, left and right directions are indicated by arrows. In FIG. 2, the front side, the rear side, the left side, and the right side are indicated by arrows.

As shown in FIG. 2, a rectangular opening 4 having an edge extending in the front-rear direction and the left-right direction is formed on the upper surface of the housing 2. Then, a platen 5 on which the original is placed is provided so as to close the opening 4 from the lower side. The platen 5 is a plate-like body formed by using a transparent material, and is, for example, a glass plate. At least the upper surface of the platen 5 is formed in a flat surface. The platen 5 is surrounded and supported by the peripheral portion of the opening 4 of the housing 2.

A CIS (Contact Image Sensor) unit 6 and a moving mechanism 7 are provided on the lower side of the platen 5.

The CIS unit 6 (an example of a reading unit) includes a light source 11, a rod lens array 12, and a light receiving unit 13 (an example of an image sensor). The light source 11 includes light emitting diodes of three colors of red, green and blue. The rod lens array 12 includes a large number of rod lenses arranged in the main scanning direction that coincides with the front-rear direction. Light of each color is sequentially irradiated from the light source 11 to the document on the platen 5, and the light of each color reflected by the document is imaged on the light receiving unit 13 through the rod lens array 12.

The light receiving unit 13 includes a plurality of sensor IC chips, for example, 12 sensor IC chips CH1 to CH12 (an example of the chip) as shown in FIG. The sensor IC chips CH1 to CH12 are arranged side by side in a row on the substrate 14 in the main scanning direction corresponding to the front-rear direction. Each sensor IC chip CH1 to CH12 includes the same number of photoelectric conversion elements 15 arranged in a row in the main scanning direction. As a result, the light receiving unit 13 includes the number of photoelectric conversion elements 15 obtained by multiplying the number of photoelectric conversion elements 15 provided in each sensor IC chip CH1 to CH12 by the number of sensor IC chips CH1 to CH12. The photoelectric conversion elements 15 form a linear image sensor in a line in the main scanning direction.

Each photoelectric conversion element 15 receives light that has passed through the rod lens array 12, and outputs a charge corresponding to the amount of light received as an electric signal of one pixel. A gain adjustment circuit, an A / D conversion circuit, and the like are mounted on the sensor IC chips CH1 to CH12. The voltage output from each photoelectric conversion element 15 is amplified by the gain adjustment circuit and then converted into a pixel value (pixel data) which is a digital value by the A / D conversion circuit. The A / D conversion circuit has, for example, a resolution of 8 bits (0 to 255), and a voltage less than the reference voltage (lower limit value) on the lower limit side is uniformly converted to "0" on the upper limit side. A voltage exceeding the reference voltage (upper limit value) is uniformly converted to "255", and a voltage in the range from the lower limit value to the upper limit value is converted into a pixel value according to the magnitude of the voltage.

In the reading result by the CIS unit 6, the pixel corresponding to the photoelectric conversion element 15 arranged at the rearmost end of the rearmost end sensor IC chip CH1 on one side in the main scanning direction is the first pixel. The final pixel is the pixel corresponding to the photoelectric conversion element 15 arranged at the frontmost end of the frontmost end sensor IC chip CH12 on the other side in the main scanning direction. One line is a pixel group composed of each pixel from the first pixel to the last pixel. The CIS unit 6 sequentially outputs pixel data (pixel values) for each pixel from the first pixel to the last pixel in reading one line.

The moving mechanism 7 is a mechanism for moving the CIS unit 6 in the sub-scanning direction orthogonal to the main scanning direction. The moving mechanism 7 includes a carriage 21 that supports the CIS unit 6, a motor 22 including a stepping motor that can rotate in the forward and reverse directions, a drive pulley 23 that is rotationally driven by the motor 22, and a driven pulley 24 that is paired with the drive pulley 23. And a belt 25 wound around the drive pulley 23 and the driven pulley 24. The drive pulley 23 is arranged at the right end of the housing 2 so that the rotation axis extends in the front-rear direction. The driven pulley 24 is arranged at the left end portion in the housing 2 so that the rotation axis extends in the front-rear direction at the same height as the rotation axis of the drive pulley 23. A carriage 21 is attached to the belt 25. The belt 25 travels due to the rotation of the drive pulley 23, and the carriage 21 moves in the sub-scanning direction that coincides with the left-right direction as the belt 25 travels.

When reading the original, the cover 3 is opened and the original is placed on the platen 5 in a state of being in contact with the left edge and the trailing edge of the opening 4 of the housing 2. After that, the cover 3 is closed, and the original is covered by the cover 3 from above. After that, when an operation of instructing the start of reading is performed by the touch panel provided in the reading device 1 or the terminal communicably connected to the reading device 1, the CIS unit 6 is moved in the sub-scanning direction by the moving mechanism 7. , The CIS unit 6 reads the documents on the platen 5 line by line. At this time, the red, green, and blue light emitting diodes of the light source 11 of the CIS unit 6 are repeatedly turned on one by one in order, and the pixel data of each color of red, green, and blue is stored in the sensor IC chips CH1 to CH12 for every three lines. It is output from each photoelectric conversion element 15.

As shown in FIG. 4, the reading device 1 includes a CPU (Central Processing Unit) 31, a non-volatile memory 32 capable of rewriting data such as a flash memory and an E2PROM, and a volatile memory 33 such as an SDRAM. .. The CPU 31, the non-volatile memory 32, and the volatile memory 33 are connected to the bus 34 for data communication.

The CPU 31 (an example of a control unit) controls each unit of the reading device 1 including the CIS unit 6 and the moving mechanism 7 by executing programs for various processes. The non-volatile memory 32 stores a program executed by the CPU 31 and various types of data. The volatile memory 33 is used as a work area when the CPU 31 executes a program.

<Reading process>
When the user places the document on the platen 5, closes the cover 3, and then performs an operation instructing the start of scanning, the CPU 31 starts the scanning process for scanning the document.

In the reading process, the CPU 31 executes an outward reading as shown in FIG. 5 (S1). In the outbound scanning, as shown in FIG. 6, the CIS unit 6 and the moving mechanism 7 are controlled, and the CIS unit 6 is moved from the origin position on the left side of the platen 5 toward the right side at a constant speed in the sub-scanning direction. At the same time, the entire area of the platen 5 in the sub-scanning direction, including the document placed on the platen 5, is read over the entire width in the main scanning direction.

The CPU 31 detects the front edge and the right edge of the document by a known edge detection method from the pixel data acquired by the outward reading. Then, the CPU 31 sets the area behind the detected front edge of the document and the area on the left side of the right edge of the document as the document area, and sets the area excluding the document area from the entire area of the platen 5 outside the document. The area is set, and the area between the left edge of the platen 5 and the right edge of the document area is set as the outbound scanning target area.

Before the outbound scanning is executed, the CIS unit 6 is moved in the sub-scanning direction at a higher speed than in the outbound scanning, and a pre-reading is executed in which a part or all of the platen 5 is read over the entire width in the main scanning direction. The original area, the outer area of the original, and the outbound scanning target area may be set from the pixel data read by the pre-reading. When the pre-reading is performed, in the outbound reading, the outbound reading target area may be read over the entire width in the main scanning direction.

Further, the CPU 31 determines whether or not each line in the outbound reading target area is a muscle candidate line. It should be noted that this operation may be executed during the execution of the outbound route reading of S1, or may be performed after the outbound route reading is completed.

Specifically, the CPU 31 increments the line number "N" by setting the line number of the line to be determined as to whether or not it is a muscle candidate line to N (N: integer) (S2). After that, the CPU 31 determines whether or not the line with the line number “N” is a muscle candidate line (S3). In this determination, the CPU 31 compares the magnitude of the pixel data (pixel value) with the predetermined threshold value for each pixel of the line of the line number "N", and determines that the pixel data below the threshold value is black level pixel data. do. Then, as shown in FIG. 7, the CPU 31 includes a plurality of black level pixel data in the pixel data of the line of the line number “N”, and the plurality of black level pixel data is the pixel data of the document area. Therefore, when the lines appear continuously in the main scanning direction, it is determined that the line with the line number “N” is the streak candidate line. When the CPU 31 determines that the line with the line number "N" is a muscle candidate line, the CPU 31 stores the line number "N" in the volatile memory 33 and associates it with the line number "N" to form the line number "N". The color of the pixel data of the "N" line and the muscle start point pixel number, which is the position of the pixel serving as the start point on the start pixel side of the continuous black level pixel data, are stored in the volatile memory 33 (S4).

After determining whether or not the line with the line number "N" is a line candidate line, the CPU 31 determines whether or not the line with the line number "N" to be determined is the final line on the rightmost end in the document area. Is determined (S5). If the line with the line number "N" is not the final line (S5: NO), the line number "N" is incremented (S2), and whether or not the incremented line with the line number "N" is a muscle candidate line. Is determined (S3). The initial value of the line number "N" is 0. Therefore, first, it is determined whether or not the line number "1", which is the most upstream line in the movement direction of the CIS unit 6 at the time of outbound reading, that is, the leftmost line, is a line candidate line, and then the final line. It is determined whether or not the line with the line number "N" is a muscle candidate line, one line at a time.

As shown in FIG. 7, for example, a threshold value as a reference for determining whether or not the pixel data is black level pixel data is set for each of the sensor IC chips CH1 to CH12 and stored in the volatile memory 33. Has been done. In the reading device 1, the back surface of the cover 3, that is, the surface facing the platen 5, is colored white, and at a predetermined timing for correction to reduce unevenness (density unevenness) of pixel data due to the characteristics of the optical system. , Pixel data when the back surface of the cover 3 is read without turning on the light source 11 of the CIS unit 6 is acquired, and black reference data is set from the pixel data. Since the photoelectric conversion elements 15 provided in the same sensor IC chips CH1 to CH12 are similarly affected by the characteristics of the optical system, the black reference data is set for each of the sensor IC chips CH1 to CH12. The threshold value that serves as a reference for determining whether or not the pixel data is black level pixel data is set to a value larger than the black reference data of each sensor IC chip CH1 to CH12 for each sensor IC chip CH1 to CH12 by a predetermined value. Set. The predetermined value may be a constant value, or may be a value obtained by multiplying the black reference data by a constant percentage α (%).

The black reference data may be set for each photoelectric conversion element 15 (per pixel), and in that case, the threshold value as a reference for determining whether or not the pixel data is black level pixel data is photoelectric conversion. It is preferable that each element 15 is set to a value larger than the black reference data of each photoelectric conversion element 15 by a predetermined value.

When the CPU 31 determines whether or not the final line is a muscle candidate line (S5: YES), whether or not there is a muscle candidate line in the outward read target area, that is, the line of the muscle candidate line in the volatile memory 33. It is determined whether or not the number is stored (S6).

When there is a muscle candidate line in the outward reading target area (S6: YES), the CPU 31 executes the muscle confirmation process (S7). In the streak confirmation process, the CPU 31 acquires the pixel data of the streak candidate line acquired in the outbound reading in the return path in which the CIS unit 6 moves from the outbound reading end position at the end of the outbound reading to the origin position in the sub-scanning direction. This is a process for determining whether or not to replace with the pixel data. The detailed contents of the muscle confirmation process will be described later.

When the CPU 31 determines the replacement of the pixel data of the streak candidate line in the streak confirmation process (S8: YES), the CPU 31 executes the replacement (replacement), and the pixel data of the outbound reading target area after the replacement is used to obtain the original area. Pixel data of each line is extracted, and the extracted pixel data is output as a document reading result to a terminal communicably connected to the reading device 1 (S9: replacement output). As a result, the reading process is completed.

On the other hand, when the CPU 31 does not have a streak candidate line in the outbound read target area (S6: NO), or when the streak confirmation process does not determine the replacement of the pixel data of the streak candidate line (S8: NO). , Pixel data of each line in the original area is extracted from the pixel data acquired by the outward reading without replacing the pixel data of the streak candidate line acquired by the outward reading, and the extracted pixel data is used as the reading result of the original. Outputs to a terminal communicatively connected to the reader 1 (S10: non-replacement output). As a result, the reading process is completed.

<Muscle confirmation process>
The flow of the muscle confirmation process executed in step S7 of FIG. 5 is shown in FIG. In the muscle confirmation process, the CPU 31 controls the movement mechanism 7 to start the movement of the CIS unit 6 on the return route from the outward reading end position at the end of the outward reading to the origin position (as shown in FIG. 9). S701). At the start of movement of the CIS unit 6, the movement speed of the CIS unit 6 is set to the first speed (S702). Further, in the streak confirmation process, the CPU 31 has a predetermined number of lines including the streak candidate line of the line number “N” stored in the volatile memory 33, for example, a fixed number N1 from the line number “N” of the streak candidate line. From the line of the line number "N-N1" minus (integer of N1: 1 or more) to the line of the line number "N + N2" which is the sum of the line number "N" and a certain number N2 (integer of N2: 1 or more). Set to the return read target area.

After that, when the CIS unit 6 moving at the first speed reaches the position on the most upstream side in the moving direction of the CIS unit 6 in the return path reading target area, that is, the return path reading start position which is the position of the line of the line number "N + N2" ( S703: YES), the CPU 31 controls the moving mechanism 7 to reduce the moving speed of the CIS unit 6 from the first speed to the second speed (S704). The second speed is set to, for example, the same speed as the moving speed of the CIS unit 6 at the time of reading the outward route. As a result, in the section from the outbound reading end position to the inbound reading start position, the CIS unit 6 is moved at the first speed higher than that in the outbound reading, and in the inbound reading target area, the CIS unit 6 is the same as in the outbound reading. Moved at speed.

In the return path reading target area, the CPU 31 is a color stored in the volatile memory 33 in association with the line number “N” of the streak candidate line among the three color light sources of the CIS unit 6 (hereinafter, this color is referred to as “N”). The light source 11 of "the color to be confirmed" is made to emit light (lights up) (S705). Then, the CPU 31 moves the CIS unit 6 in the sub-scanning direction, and receives the reflected light from the back surface of the cover 3 of the light of the confirmation target color and the document by the CIS unit 6, thereby reading the return path to the CIS unit 6. The target area is read line by line (S706: return reading). As a result, the CPU 31 acquires pixel data of the color to be confirmed for each line in the return reading target area.

Then, the CPU 31 refers to the pixel data of each line in the return path read target area in order from the first pixel, and the black level pixel data is stored in the volatile memory 33 in association with the line number “N” of the streak candidate line. It is determined whether or not the pixels of the streak starting point pixel number appear consecutively (S707).

When black level pixel data appears consecutively from the pixel of the streak start point pixel number in the pixel data of any line in the return path scanning area, the streak consisting of the black level pixel data is drawn in the manuscript. It is considered to be a line. Therefore, when the black level pixel data continuously appears from the pixel of the streak start point pixel number in the pixel data of any line in the return path reading target area (S707: YES), the CPU 31 acquires the line number in the outward path reading. It is determined that the pixel data of the "N" streak candidate line is output without replacing the pixel data of the black level pixel data with the pixel data of the line appearing continuously from the pixel of the streak start point pixel number by the return path reading (S708: non-). Replacement decision).

On the other hand, when the black level pixel data does not continuously appear from the pixel of the streak start point pixel number in the pixel data of any line in the return path reading target area, the pixel data of the streak candidate line acquired by the CPU 31 in the outward path reading is It is considered that the CIS unit 6 contains black level pixel data generated by mixing noise. Therefore, the CPU 31 decides to replace the pixel data of the line number "N" line candidate line acquired in the outward reading with the pixel data of the line number "N" acquired in the inbound reading and output it (S709: Replacement decision).

After that, the CIS unit 6 moving at the second speed reaches the position on the most downstream side in the moving direction of the CIS unit 6 in the return path reading target area, that is, the return path reading end position which is the position of the line of the line number "NN1". Then (S710: YES), the CPU 31 controls the moving mechanism 7 to increase the moving speed of the CIS unit 6 from the second speed to the first speed (S711). As a result, the CIS unit 6 moves at high speed toward the origin position after passing the return reading end position.

Then, when the CIS unit 6 reaches the origin position (S712: YES), the CPU 31 ends the movement of the CIS unit 6 on the return route (S713). With this, the streak confirmation process is completed, the process executed by the CPU 31 returns to the read process shown in FIG. 7, and the CPU 31 executes the processes after step S8 of the read process.

<Effect>
As described above, in the outward path in which the CIS unit 6 is moved from the origin position to the outward path reading end position in the sub-scanning direction, the pixel data of each line extending in the main scanning direction is output from the light receiving unit 13. The CPU 31 determines whether or not each pixel data output from the light receiving unit 13 is black level data, and has a streak candidate line in which a plurality of black level data continuously appear in the main scanning direction. Is judged. When there is a streak candidate line, in the return path in which the CIS unit 6 returns from the outward reading end position toward the origin position, a plurality of black levels are added to the pixel data of the streak candidate line based on the pixel data output from the light receiving unit 13. It is confirmed whether or not the data appears continuously in the main scanning direction.

Then, when it is confirmed that a plurality of black level data appear continuously in the main scanning direction in the pixel data of the streak candidate line on the return path, the light receiving unit 13 outputs the data when the CIS unit 6 moves on the outward path. The pixel data of each line is output from the CPU 31. Further, even when it is determined that there is no muscle candidate line in the outward route, the pixel data of each line output from the light receiving unit 13 when the CIS unit 6 moves in the outward route is output from the CPU 31.

On the other hand, it was determined that there was a muscle candidate line on the outward route, but on the return route, a plurality of black level data should not appear continuously in the main scanning direction in the pixel data of the muscle candidate line output from the light receiving unit 13. If is confirmed, the pixel data of each line output from the light receiving unit 13 on the outward route is replaced with the pixel data of the muscle candidate line output from the light receiving unit 13 on the return route. Is output from the CPU 31.

Therefore, in the reading device 1, it is possible to obtain a better reading result than the configuration in which the pixel data of the streak candidate line is replaced with the pixel data of another line and output.

In the streak confirmation process, a predetermined number of lines including the streak candidate line of line number “N” are set in the return path read target area, and the pixel data of the return path read target area is output from the light receiving unit 13. As a result, an extra area other than the return reading target area required for confirming whether or not a plurality of black level data continuously appear in the pixel data of the streak candidate line in the main scanning direction cannot be read. , The time required for the muscle confirmation process can be shortened.

Further, on the return route, the movement speed of the CIS unit 6 is set to the first speed until the CIS unit 6 reaches the return route read target area, and when the CIS unit 6 reaches the return route read target area, the CIS unit 6 moves. The speed is reduced from the first speed to the second speed, which is slower than the first speed. The second speed is the same speed as the moving speed of the CIS unit 6 on the outward route. Therefore, in other words, on the return route, the CIS unit 6 is moved at a speed higher than the movement speed on the outward route until it reaches the region to be read on the return route, and when it reaches the region to be read on the return route, it is at the same speed as the movement speed on the outward route. Will be moved. As a result, the time required for the CIS unit 6 to reach the return path reading target area can be shortened, and the return path reading target area can be satisfactorily read by the CIS unit 6. As a result, it is possible to further shorten the time required for the streak confirmation process, and accurately confirm whether or not a plurality of black level data appear continuously in the main scanning direction in the pixel data of the streak candidate line. be able to.

While the CIS unit 6 passes through the return reading target area, the light source 11 of the CIS unit 6 is turned on. At this time, it is stored in the volatile memory 33 in association with the line number "N" of the muscle candidate line. The light emitting diode of the color to be confirmed is turned on. As a result, in the outward reading, as shown in FIG. 10A, red (R), green (G), and blue (B) pixel data are acquired in the three lines including the muscle candidate line, but in the returning reading, the red (R), green (G), and blue (B) pixel data are acquired. As shown in FIG. 10B, red (R) pixel data is acquired for all three lines including the streak candidate line. Therefore, even if there is a slight deviation (a deviation of 1 line or less) between the position of the CIS unit 6 detected by the CPU 31 and the actual position of the CIS unit 6 from the output signal of the encoder provided attached to the motor 22, the outbound route It is possible to satisfactorily determine whether or not to replace the pixel data of the line number “N” line candidate line acquired by reading with the pixel data of the line number “N” acquired by return reading.

Whether or not the pixel data is black level pixel data is determined by whether or not the pixel data is less than the threshold value. The threshold value that serves as a reference for the determination is set for each of the sensor IC chips CH1 to CH12. The photoelectric conversion elements 15 provided in the same sensor IC chips CH1 to CH12 are similarly affected by the characteristics of the optical system. Therefore, by setting the threshold value for each of the sensor IC chips CH1 to CH12, the pixel data becomes black level. The number of thresholds stored in the volatile memory 33 can be reduced as compared with the configuration in which the thresholds are set for each photoelectric conversion element 15 while being able to satisfactorily determine whether or not the data is pixel data. Can be done.

<Modification example>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other embodiments.

For example, in the above-described embodiment, the muscle candidate line is detected in the outward reading, and in the muscle confirmation process, the black level pixel data is the starting point of the pixel data of any line in the return reading target area including the muscle candidate line. When it is determined that the pixels of the pixel number do not appear consecutively, the pixel data of the line number "N" streak candidate line acquired in the outward reading is the pixel data of the line number "N" acquired in the inbound reading. It was assumed that it would be output by replacing it with. However, not limited to this, of the muscle candidate lines acquired by the outward reading, the portion where the black level pixel data is continuous is targeted for replacement, and the pixel data of the target portion is the target portion acquired by the returning reading. It may be replaced with the pixel data of. As a result, the number of pixel data to be replaced can be reduced, and unnecessary replacement of pixel data can be eliminated.

Further, in the return path reading of the muscle confirmation process, while the CIS unit 6 passes through the return path reading target area, the light emission of the confirmation target color stored in the volatile memory 33 in association with the line number “N” of the muscle candidate line. It is assumed that the diode (light source 11) is turned on. However, during the return route reading, the red, green, and blue light emitting diodes of the light source 11 may be repeatedly lit one by one in order, as in the case of the outward route reading. In this case, in the muscle confirmation process, the CPU 31 replaces the pixel data of the line number “N” line candidate line acquired in the outward reading with the pixel data of the line number “N” acquired in the returning reading and outputs the pixel data. In addition, the pixel data of a plurality of lines including the line number "N" line candidate line acquired in the outward reading may be replaced with the pixel data of the plurality of lines acquired in the returning reading and output.

Furthermore, although it was determined that there was a muscle candidate line on the outward route, a plurality of black level data did not appear continuously in the main scanning direction in the pixel data of the muscle candidate line output from the light receiving unit 13 on the return route. When confirmed, the pixel data of the muscle candidate line output from the light receiving unit 13 on the outward route is replaced with the pixel data of the muscle candidate line output from the light receiving unit 13 on the return route. Not limited to this, it was determined that there was a streak candidate line on the outward route, but a plurality of black level data did not appear continuously in the main scanning direction in the pixel data of the streak candidate line output from the light receiving unit 13 on the return route. When it is confirmed that the outbound route reading is executed again, the pixel data of the muscle candidate line output from the light receiving unit 13 on the outward route is obtained from the pixel data of the muscle candidate line output from the light receiving unit 13 during the reoutbound route reading. May be replaced.

Further, in the above-described embodiment, the case where the CPU 31 executes each process has been described. However, the reading device 1 may include a plurality of CPUs 31, and the plurality of CPUs 31 may cooperate to execute each process.

Further, in the above-described embodiment, the case where the CPU 31 outputs the reading result of the document to the terminal communicably connected to the reading device 1 has been described. However, for example, in a multifunction device in which a printing mechanism and a reading mechanism are integrated, the pixel data read by the reading mechanism may be used as the reading result of the original to be printed by the printing mechanism. That is, "output of pixel data (reading result)" means that pixel data (reading result) is output from the volatile memory 33 used by the CPU 31 as a work area, regardless of the output destination. ..

In addition, various design changes can be made to the above-mentioned configuration within the scope of the matters described in the claims.

1: Reader 6: CIS unit 7: Moving mechanism 11: Light source 15: Photoelectric conversion element 31: CPU
CH1 to CH12: Sensor IC chip

Claims (11)

A reading unit that has an image sensor in which a plurality of photoelectric conversion elements are arranged in the main scanning direction and reads a document,
A moving mechanism that moves the reading unit in the sub-scanning direction orthogonal to the main scanning direction, and
With a control unit
The control unit
In the outward path in which the reading unit is moved from the scanning start position to the scanning end position on one side in the sub-scanning direction by the moving mechanism, the document is read and the pixel data of each line extending in the main scanning direction is acquired. Processing and
It is determined whether or not each pixel data output from the image sensor by the outbound reading process is black level data, and a plurality of the black level data appear continuously in the main scanning direction. Presence / absence judgment processing to judge the presence / absence of
When it is determined by the presence / absence determination process that there is the streak candidate line, the image sensor reads the document on the return path in which the reading unit is moved from the reading end position to the other side in the sub-scanning direction by the moving mechanism. A streak confirmation process for acquiring pixel data from the streak candidate line and determining whether or not a plurality of the black level data continuously appear in the streak candidate line in the main scanning direction.
When it is determined in the presence / absence determination process that the streak candidate line does not exist, or when it is determined in the streak confirmation process that the line appears, the non-replacement output process of outputting the pixel data of each line in the outbound reading process as it is. ,
When it is determined in the streak confirmation process that a plurality of the black level data do not appear consecutively in the main scanning direction, among the pixel data of each line in the outbound reading process, the pixel data of the streak candidate line Is replaced with the pixel data of the muscle candidate line acquired during or after the muscle confirmation process, and the pixel data of each line other than the muscle candidate line is replaced with the pixel data of the outward reading process as it is. A reader that performs output processing and. The reading device according to claim 1.
When the control unit determines in the streak confirmation process that a plurality of the black level data do not appear consecutively in the main scanning direction, the pixels of the lines output from the image sensor in the outbound reading process. A reading device that replaces the pixel data of the muscle candidate line among the pixel data of the muscle candidate line with the pixel data of the muscle candidate line output from the image sensor at the time of the muscle confirmation process and outputs the data. The reading device according to claim 1 or 2.
The control unit is a reading device that outputs pixel data of a predetermined number of lines including the muscle candidate line from the image sensor in the muscle confirmation process. The reading device according to claim 3.
In the muscle confirmation process, the control unit sets the moving speed of the reading unit by the moving mechanism to the first speed until the reading unit reaches the reading position of the predetermined number of lines by the image sensor. A reading device that reduces the moving speed of the reading unit by the moving mechanism to a second speed lower than the first speed when the reading unit reaches the reading position of the predetermined number of lines by the image sensor. The reading device according to claim 4.
The second speed is a speed at which the reading unit is moved by the moving mechanism in the outbound reading process. The reading device according to any one of claims 3 to 5.
The control unit is a reading device that lights a light source of the reading unit while the reading unit is located at a reading position of the predetermined number of lines by the image sensor in the muscle confirmation process. The reading device according to any one of claims 1 to 6.
The image sensor outputs pixel data for each of the red, green, and blue colors, and outputs pixel data.
The control unit
In the presence / absence determination process, the presence / absence of the streak candidate line is determined for each of the red, green, and blue colors.
When it is determined that there is the streak candidate line in the presence / absence determination process, the color of the pixel data of the streak candidate line is stored.
A reading device that acquires pixel data of the stored color from the image sensor in the streak confirmation process. The reading device according to any one of claims 1 to 7.
The control unit is a reading device that replaces the black level data continuous in the main scanning direction among the pixel data of the streak candidate line in the replacement output process. The reading device according to any one of claims 1 to 8.
The control unit is a reading device that replaces pixel data of a plurality of lines including the muscle candidate line in the replacement output process. The reading device according to any one of claims 1 to 9.
The control unit sets a threshold value for each pixel data in the presence / absence determination process, and when the pixel data is less than the threshold value set in the pixel data, the pixel data is determined to be the black level data. Judgment, reader. The reading device according to any one of claims 1 to 10.
The image sensor has a plurality of chips arranged in the main scanning direction, and in each chip, a predetermined number of the photoelectric conversion elements are arranged in the main scanning direction.
In the presence / absence determination process, the control unit sets a threshold value for each chip, and when the pixel data is less than the threshold value set for the chip having the photoelectric conversion element corresponding to the pixel data, the control unit is concerned. A reading device that determines that the pixel data is the black level data.

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