JP3996014B2 - Image recognition processor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image recognition processing apparatus.
[0002]
[Prior art]
In a point-of-sale information management system that collects, registers, stores, and analyzes sales information for each product, a barcode that is printed or pasted on the product is used. The barcode is a striped pattern in which information related to the product is displayed by a combination of bar lines having different thicknesses, and the product information is read by a barcode recognition photographing system which is one type of image recognition processing device.
[0003]
FIG. 6 is a block diagram showing a simplified configuration of a conventional barcode recognition photographing system 1. A conventional barcode recognition photographing system 1 will be described with reference to FIG. The barcode recognition photographing system 1 includes a camera mechanism unit 2, an image sensor 3, a clock generator 4, an image processing unit 5, a signal processing unit 6, a central processing circuit 7 (abbreviated as CPU), a memory 8, and The display unit 9 and the CPU bus 10 connecting the above-described units are included.
[0004]
The camera mechanism unit 2 includes, for example, an optical lens, and photographs the barcode 11 that is a subject. Optical information of the barcode 11 photographed by the camera mechanism unit 2 is photoelectrically converted by the image sensor 3. The image sensor 3 is composed of, for example, a CCD (Charge Coupled Device), and outputs the image sensor reading analog signal 13 to the image processing unit 5 for each pixel in accordance with the image sensor control signal 12 output from the clock generator 4. The image processing unit 5 performs analog / digital conversion for each pixel of the image sensor read analog signal 13 output from the image sensor 3 in accordance with the image sampling clock 14 output from the clock generator 4, and digitized image data The signal 15 is output to the signal processing unit 6.
[0005]
The image data signal 15 is first converted in data format by a format conversion unit 16 provided in the signal processing unit 6. For example, when the data format of the image data signal 15 output from the image processing unit 5 is RGB888 used for image display on the liquid crystal panel, the format conversion unit 16 uses the data format RGB888 for image display on the liquid crystal panel as well. Are converted into a data format such as YUV422 or YUV420, which is an intermediate format of RGB565, JPEG (Joint Photographic Experts Group) format. In the conventional barcode recognition photographing system 1, one type of data format of the image data converted and output by the format conversion unit 16 is set by the register control signal 18 from the register 17 provided in the signal processing unit 6. . Assume that the data format of the image data signal 19 converted and output by the format converter 16 is, for example, YUV422.
[0006]
The image data signal 19 output from the format conversion unit 16 is stored in the temporary buffer C20. The buffer C20 is a buffer memory provided to absorb a time lag with respect to the reading process of the CPU 7 performed asynchronously and intermittently.
[0007]
The CPU 7 once transfers the image data of the data format YUV422 for one screen from the buffer C 20 to the memory 8 via the CPU bus 10. The CPU 7 develops the image data in the data format YUV422 transferred to the memory 8 and separates it into a Y signal that is a luminance signal and a U signal and a V signal that are color difference signals. Recognize images.
[0008]
In order to accurately recognize the barcode 11, the CPU 7 has, for example, a liquid crystal display (LCD) as a user interface so that the imaging distance of the camera mechanism unit 2 can be easily adjusted to the position of the barcode displayed on the product. The image of the barcode 11 is displayed in real time on the display unit 9 consisting of When the image is displayed on the display unit 9, the CPU 7 converts the data format YUV422 into RGB565, which is a data format suitable for the display unit 9 composed of an LCD, and outputs the converted data.
[0009]
As described above, in the conventional barcode recognition photographing system 1, since the data format of the image data output from the signal processing unit 6 is one type selected in advance, the image recognition of the barcode 11 is performed in the processing by the CPU 7. For this reason, the Y signal must be extracted and the data format must be converted for image display, which requires a long processing time. Although it is possible to use a high-performance CPU, memory, and dedicated hardware for compression algorithms in order to reduce the processing speed, the price will rise rapidly as the performance of the hardware increases. There is no problem.
[0010]
Also, in order to realize barcode image recognition and display on a display unit using only image data of one type of data format, monochrome gradation display is performed using the Y signal extracted for barcode image recognition. It has been tried. However, in monochrome gradation display, there is a problem that it is difficult to determine the display position of the barcode and the imaging distance of the camera mechanism unit with respect to the display position.
[0011]
[Problems to be solved by the invention]
An object of the present invention is to provide an image recognition processing apparatus capable of executing an image recognition process and an image display process at high speed with a simple configuration.
[0012]
[Means for Solving the Problems]
The present invention includes a camera mechanism for taking an image,
An image sensor that photoelectrically converts image data captured by the camera mechanism;
An image processing unit that performs an analog / digital conversion process on an electrical signal of image data output from the image sensor;
Signal processing for converting image data output from the image processing unit into image data of two data formats each having a data amount smaller than the data amount of the image data and represented by RGB and luminance (Y). A first buffer for storing image data of one data format among the converted data, a second buffer for storing image data of the other data format among the converted data, a signal processing unit for chromatic and a selector which is connected to the second buffer,
A memory for store the converted image data by the signal processing unit,
Display means for displaying the image data;
The selector is controlled so that image data is transferred from the first buffer and the second buffer to the memory, the image data stored in the respective formats is read out from the memory, and the image data in the data format represented by luminance is read. And a control means for displaying image data in a data format represented by RGB on the display means.
[0013]
According to the present invention, the signal processing unit is suitable for image display on a liquid crystal display (LCD) , which is imaged by a camera mechanism unit, photoelectrically converted by an image sensor, and digitized by an image processing unit. The image data is converted into image data of two data formats respectively represented by RGB and luminance (Y) suitable for RGB and luminance (Y) suitable for barcode recognition using a Y signal which is a luminance signal . These image data converted into two data formats are stored respectively in the first and second buffer. The control means can control and output the image data converted into a different data format for each data format by controlling the selector. As a result, the control means can transfer any image data converted into a different data format suitable for image recognition and image display to the memory at an arbitrary timing. Control means reads the image data stored in the memory in different data formats, as well as image recognition based on image data of a data format represented by luminance (Y) suitable for image recognition, in RGB suitable for image display An image is displayed on the display means based on the image data of the represented data format. Thus, the control means, based on the converted de Tafoma' preparative image recognition and image display and the advance signal processing unit to be suitable, respectively, since the processing of image recognition and image display, shortening the processing time Is done.
[0014]
In the invention, it is preferable that the control unit simultaneously reads out the image data stored in the memory in different data formats.
[0016]
According to the present invention, the control means can be read out simultaneously the image data to be stored in memory in different data formats, executes image recognition processing and image display processing based on the read out image data Therefore, the processing time is shortened.
[0021]
In addition, the present invention is characterized by further including an imaging position setting means capable of variably setting an imaging position by the camera mechanism section.
[0022]
According to the present invention, the image forming apparatus further includes image forming position setting means capable of variably setting the image forming position by the camera mechanism unit, so that the shooting distance between the subject and the camera mechanism unit is shortened and the image is formed on the image sensor. It is possible to enlarge the image of the subject. As a result, efficient use of effective pixels of the image sensor is realized, so that the accuracy of image recognition can be further improved.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
In the present embodiment, a barcode recognition photographing system that is one of image recognition processing apparatuses is illustrated. FIG. 1 is a block diagram showing a simplified configuration of a barcode recognition photographing system 30 according to an embodiment of the present invention.
[0024]
The barcode recognition photographing system 30 includes a camera mechanism unit 32 for photographing an image of a barcode 31 that is a subject, an image sensor 33 that photoelectrically converts image data photographed by the camera mechanism unit 32, and an image sensor 33. An image processing unit 34 that performs analog / digital conversion processing on the electrical signal of the output image data; a clock generator 35 that outputs a control signal related to image data collection and image data conversion to the image sensor 33 and the image processing unit 34; a signal processing unit 36 for converting image data outputted from the image processing unit 34 to a different data format, the image data converted to a different data format, a memory 37 for store, display means for displaying the image data 38 (referred to as the display portion in the drawing), reads the image data to be store in the memory 37, the image certification A central processing circuit (CPU) is a control means 39 to be displayed on the display unit 38 as well as, and a CPU bus 59 which connects the respective units described above.
[0025]
The camera mechanism unit 32 includes an optical lens, captures the barcode 31, and gives an optical signal related to the barcode image to the image sensor 33. The image sensor 33 is constituted by a CCD, photoelectrically converts an optical signal related to the image of the barcode 31 provided from the camera mechanism 32, and reads an image sensor for each pixel according to the image sensor control signal 40 from the clock generator 35. The signal 41 is output to the image processing unit 34. The imaging device 33 is not limited to a CCD, and may be a solid-state imaging device such as a CMOS (Complementary Metal Oxide Semiconductor). The image processing unit 34 performs analog / digital conversion on the image sensor read analog signal 41 for each pixel in accordance with the image sampling clock 42 from the clock generator 35, and outputs a digitized image data signal 43 to the signal processing unit 36. . In the present embodiment, the data format of the digitized image data signal 43 is RGB888.
[0026]
The signal processing unit 36 includes a format converter 44 for converting the image data signals 43 described above in two different data formats, the Y signal separation unit 45 that only the separating extracted Y signal from the transformed one of the data format, A decoder 46 that selects the Y signal at an arbitrary bit rate, a buffer A 47, a buffer B 48, and a selector 49 that is a switching means for switching and outputting image data converted into two different data formats for each data format; , And a register 50.
[0027]
The format conversion unit 44 converts the format of the image data signal 43 input in the data format RGB888 into a data format YUV422 suitable for image recognition of the barcode 31 and a data format RGB565 suitable for image display of the barcode 31. The conversion from the data format RGB to the data format YUV is performed by linear conversion of multiplying a predetermined coefficient in each of the R signal, the G signal, and the B signal, and adding the multiplication results, and thereby the Y signal and the color difference that are luminance signals. Signals U and V can be obtained. These converted data formats YUV422 and RGB 565 have different image sizes.
[0028]
The image data signal converted into the data format YUV422 is referred to as a first image data signal 51 for convenience, and the image data signal converted into the data format RGB565 is referred to as a second image data signal 52 for convenience. In this embodiment, the data format converted by the format conversion unit 44 is the data format YUV422 and the data format RGB565, but a data format other than the above is selected by the register control signal 53 output from the register 50. You can also
[0029]
The Y signal separation unit 45 deletes the U signal and the V signal from the first image data signal 51 converted into the 16-bit data format YUV422, and separates and extracts the 8-bit Y signal 54. The decoding unit 46 converts the Y signal 54 into an arbitrary number of 1 to 8 bits according to the setting by the register 50, and outputs it as a decoded signal 55.
[0030]
Hereinafter, signal processing in the Y signal separation unit 45 and the decoding unit 46 will be described. FIG. 2 is a diagram showing a data arrangement in the case of outputting an image data signal of 2n pixel data format YUV422 via a 16-bit CPU bus 59, and FIG. 3 is a diagram showing a data arrangement of a separated Y signal 54. FIG. 4 is a diagram showing a data arrangement when the Y signal 54 is compressed to 4 bits.
[0031]
In order for the CPU 39 to read the image data composed of the Y signal, U signal and V signal converted into the data format YUV422, 2n reading operations are required. However, if the Y signal separation unit 45 deletes the U signal and the V signal from the first image signal 51 and separates and extracts only the Y signal 54, it is only necessary to read the Y signal 54 n times. Further, when the Y signal 54 is compressed to 4 bits by the decoding unit 46 and converted into the decoding signal 55 having the data arrangement as shown in FIG. 4, the decoding signal 55 is read out by n / 2 reading operations. That's it. In this way, by separating only the Y signal 54 and further compressing the Y signal 54 by the decoding unit 46, the time for reading out image data by the CPU 39 is shortened, and the barcode image recognition processing load is reduced. . For the data compression of the Y signal 54 in the decoding unit 46, a known method such as a method of simply thinning out lower bits of data or a method of performing arbitrary weighting is used.
[0032]
Returning to FIG. 1 again, the buffer A 47 and the buffer B 48 are buffer memories provided to absorb a time lag with respect to the processing timing of the CPU 39. The buffer A47 stores the decoded signal 55 of the Y signal 54 that has been compressed, and the buffer B48 stores the second image data signal 52 of the data format RGB565.
[0033]
Buffer A 47 and buffer B 48 are connected to selector 49. The CPU 39 gives another register control signal 56 for controlling the switching operation of the selector 49 to the selector 49 via the register 50 according to the data format to be read, and receives the decode signal 55 or the second signal from the buffer A47 or the buffer B48. Image data signal 52 is read and transferred to memory 37. The decode signal 55 which is transferred to the memory 37 and the second image data signals 52, is store for each data format.
[0034]
The CPU 39 can simultaneously read the decode signal 55 and the second image data signal 52 stored in the memory 37, execute image recognition of the barcode 31 based on the read decode signal 55, and read the same. Based on the second image data signal 52 which is image data of the data format RGB565, a bar code image is displayed on the display means 38 constituted by the LCD.
[0035]
As described above, the CPU 39 can execute image recognition and image display of the barcode 31 based on each of the image data signals converted into the two different data formats YUV422 and RGB565 by the format conversion unit 44 in advance. it can. In addition, for the data format YUV422, since only the Y signal 54 is separated and the barcode image recognition is executed by the decode signal 55 obtained by compressing the Y signal 54, the data reading process is compared with the data in the data format YUV422. Time is shortened. Furthermore, the image data signals converted into two types of data formats and stored in the memory 37 can be read simultaneously, and the image recognition and image display of the barcode 31 can be executed simultaneously. As a result, the time required for image recognition and image display processing of the CPU 39 can be reduced.
[0036]
FIG. 5 is a block diagram showing a simplified configuration of a barcode recognition photographing system 60 according to the second embodiment of the present invention. The barcode recognition imaging system 60 of the present embodiment is similar to the barcode recognition imaging system 30 of the first embodiment, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. What should be noted in the barcode recognition imaging system 60 is that it includes an imaging position setting means 61 that can variably set the imaging position by the camera mechanism section 32.
[0037]
The imaging position setting unit 61 includes a holding member 62 that holds the lens, and a moving unit 63 that moves the lens to be held in the direction of the arrow 64, that is, in the direction of approaching and moving away from the barcode 31 that is the subject. Is done. The moving means 63 is, for example, a sliding screw that engages a holding member 62 engraved with a female screw with a sliding screw rod and rotates the sliding screw rod to advance and retract the holding member 62 holding the lens in the direction of the arrow 64. It is realized by a mechanism.
[0038]
The lens provided in the camera mechanism unit 32 is a single focus lens having the same focal length: f on one side and the other side on the optical axis of the lens. Further, the distance on the optical axis between the barcode 31 as a subject and the lens is a, and the distance on the optical axis between the imaging element 33 and the lens arranged at the image point on which the barcode 31 image is to be formed. Where b is an imaging formula using the above-mentioned focal length: f is given by equation (1).
1 / a + 1 / b = 1 / f (1)
[0039]
From formula (1), it can be seen that when the focal length f is determined, the distance b can be increased by decreasing the distance a. That is, by bringing the lens of the camera mechanism unit 32 close to the barcode 31, the image of the barcode 31 imaged on the imaging device 33 can be enlarged, so that the effective pixels of the imaging device 33 are efficiently used. And the accuracy of image recognition can be further improved.
[0040]
As described above, in the present embodiment, the subject image to be recognized is a barcode, but is not limited to this, and the subject image may be, for example, a mark sheet. Therefore, the image recognition processing apparatus is not limited to the barcode recognition photographing system, but may be another mark sheet recognition photographing system, for example.
[0041]
【The invention's effect】
According to the present invention, the signal processing unit is suitable for displaying an image on the liquid crystal display (LCD) , which is imaged by the camera mechanism unit, photoelectrically converted by the imaging device, and digitized by the image processing unit. The image data is converted into image data of two data formats respectively represented by RGB and luminance (Y) suitable for RGB and luminance (Y) suitable for barcode recognition using a Y signal which is a luminance signal . These image data converted into two data formats are stored respectively in the first and second buffer. The control means can control and output the image data converted into a different data format for each data format by controlling the selector. As a result, the control means can transfer any image data converted into a different data format suitable for image recognition and image display to the memory at an arbitrary timing. Control means reads the image data stored in the memory in different data formats, as well as image recognition based on image data of a data format represented by luminance (Y) suitable for image recognition, in RGB suitable for image display An image is displayed on the display means based on the image data of the represented data format. Thus, the control means, based on the converted de Tafoma' preparative image recognition and image display and the advance signal processing unit to be suitable, respectively, since the processing of image recognition and image display, shortening the processing time Is done.
[0042]
According to the invention, the control means can be read out simultaneously the image data to be stored in memory in different data formats, executes the image recognition processing and image display processing based on the read out image data Therefore, the processing time is shortened.
[0045]
In addition, according to the present invention, the image forming apparatus further includes an image forming position setting unit capable of variably setting the image forming position by the camera mechanism unit, so that the shooting distance between the subject and the camera mechanism unit is shortened and the image is formed on the image sensor It is possible to enlarge the image of the subject to be viewed. As a result, efficient use of effective pixels of the image sensor is realized, so that the accuracy of image recognition can be further improved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a simplified configuration of a barcode recognition photographing system 30 according to an embodiment of the present invention.
FIG. 2 is a diagram showing a data arrangement when an image data signal of a data format YUV422 with 2n pixels is output via a 16-bit CPU bus 60. FIG.
FIG. 3 is a diagram showing a data array of separated Y signals 54;
FIG. 4 is a diagram showing a data arrangement when Y signal 54 is compressed to 4 bits.
FIG. 5 is a block diagram showing a simplified configuration of a barcode recognition photographing system 60 according to a second embodiment of the present invention.
FIG. 6 is a block diagram showing a simplified configuration of a conventional barcode recognition photographing system 1;
[Explanation of symbols]
30, 60 Barcode recognition imaging system 31 Barcode 32 Camera mechanism section 33 Image sensor 34 Image processing section 35 Clock generator 36 Signal processing section 37 Memory 38 Display section 39 Control section 44 Format conversion section 45 Y signal separation section 46 Decoding section 47 Buffer A
48 Buffer B
49 selector 61 imaging position setting means

Claims (3)

A camera mechanism for taking an image;
An image sensor that photoelectrically converts image data captured by the camera mechanism;
An image processing unit that performs an analog / digital conversion process on an electrical signal of image data output from the image sensor;
Signal processing for converting image data output from the image processing unit into image data of two data formats each having a data amount smaller than the data amount of the image data and represented by RGB and luminance (Y). A first buffer for storing image data of one data format among the converted data, a second buffer for storing image data of the other data format among the converted data, a signal processing unit for chromatic and a selector which is connected to the second buffer,
A memory for store the converted image data by the signal processing unit,
Display means for displaying the image data;
The selector is controlled so that image data is transferred from the first buffer and the second buffer to the memory, the image data stored in the respective formats is read out from the memory, and the image data in the data format represented by luminance is read. And a control means for displaying image data in a data format represented by RGB on the display means. The control means includes
2. The image recognition processing apparatus according to claim 1, wherein the image data stored in the memory is simultaneously read out in different data formats. Image recognition processing apparatus according to claim 1 or 2, further comprising an imaging position setting means capable of setting the imaging position of the camera mechanism variably.

Images