KR20060033378A - Three dimensional measurement camera by slit beam method with comparing circuit - Google Patents

Abstract

The present invention can reduce the amount of data to be processed by the external processor to process the luminance value obtained by the pixel array of the image sensor at a higher speed, and also to achieve this processing speed more economically, In addition, the present invention relates to a three-dimensional image measuring camera that can more efficiently process the three-dimensional image measurement of a plurality of objects.

Camera 3d image

Description

Three Dimensional Measurement Camera by Slit Beam Method with Comparing Circuit}

1 is a schematic diagram for explaining a slit light scanning method according to the present invention.

        FIG. 2 is a specific example showing luminance values of one row of one frame in which an object is photographed according to the slit light scanning method of FIG. 1.

        3 is a block diagram showing an operating state of a digital image sensor (hereinafter referred to as "DIS") according to the present invention.

        Figure 4 (A) is a schematic diagram of one embodiment of a shape measuring camera having a comparison circuit according to the present invention, Figure 4 (B) is a schematic diagram of another embodiment, and Figure 4 (C) is a schematic block diagram of another embodiment.

        5 is a flowchart schematically illustrating a process of measuring a three-dimensional shape of an object through a camera according to the present invention.

FIG. 6 is a flowchart more specifically describing steps S300 and S400 in FIG.

* Brief description of the main symbols in the drawings *

        100: digital image sensor unit (DIS)                 

        110: pixel array

        111: pixel

        120: A / D converter (ADC)

        130: ADC memory

        131: ADC register

        132: ADC output register

        140: output port

        200: luminous intensity value comparison circuit

        300: control unit

        410: Image memory

        420: maximum brightness position value memory

        430: maximum brightness value memory

        431: First maximum luminance value memory

        432: second maximum brightness value memory

        510: Slit Beam Diode

        520: object

        530: Sensor

        540: Lens

Field of invention

The present invention relates to a three-dimensional shape measuring camera having a comparison circuit therein. More specifically, the present invention is a camera for measuring the three-dimensional shape of the object through the slit light scanning method, the camera having a comparison circuit for measuring the position of the maximum intensity value for each row of the pixel array therein It is about.

Background of the Invention

       Measuring the three-dimensional shape and dimensions of precision workpieces such as machinery, optics and their parts using machine vision is a very important process in the process of improving precision in the machine parts manufacturing industry. come. In addition, in recent years, the demand for measuring fine pattern shapes in the semiconductor and computer auxiliary memory industries as well as machine parts is increasing. In addition, the demand for 3D shape measurement for computer graphics in human body measurement and various image media is increasing. It is also increasing.

        As one method of the three-dimensional shape measurement, the slit light scanning method is shown in FIG. By attaching a cylindrical lens to the output terminal of the laser diode 510, the laser beam is scanned into the object 520 in the form of a slit, and the image of the slit light 550, which is deformed as the height of the object surface changes, through the imaging optical system. An image is imaged on a pixel array of the image sensor 530.                         

       In each pixel of the pixel array, an intensity value of incident slit light is given. In FIG. 2, an intensity value of one row of a frame photographed according to the slit light scanning method of FIG. 1 is illustrated. Assuming that the resolution of the sensor is n × m (that is, it means n pixels horizontally and m vertically), the value of the row from the reference point (that is, the vertical direction from the reference point) Second pixel) linearly corresponds to the position on the object's plane (“y” in FIG. 1), and the value of the column (i.e., how many pixels in the horizontal direction from the reference point) is the height of the object. ("H" in Fig. 1) corresponds linearly. Therefore, the value of the column of pixels where the luminosity value is the maximum for each row is the height of the object at that row (that is, the “y” position) (depending on how the reference point is determined, Since the meaning is different, in the present specification, unless otherwise specified, it is assumed that the reference point is set such that the value of the row of the pixel array corresponds to the position on the object plane and the value of the column corresponds to the height of the object).

        However, since the three-dimensional shape measured by the image sensor is only an image of one end surface in which the slit light is scanned on the object (the cross section cut in the y direction at a specific “x” position in FIG. 1), such as a conveyor belt. By moving the object or image sensor through the stage, three-dimensional shapes of all the slit lights obtained through almost continuous shooting can be continuously combined to obtain a three-dimensional shape of the entire object. Since a three-dimensional shape can be obtained, it is not necessary to consider only the “x” value separately in FIG. 1 unless there is another purpose.

        Looking at the operation of the camera for the three-dimensional shape acquisition as follows. The camera photographs a moving object at a predetermined speed and transmits luminance values for all pixels acquired for each frame to a separate processor (external computer, not shown). The processor obtains the height value by comparing the luminance values for all the pixels of the transmitted frame in units of rows and obtaining the value of the column having the maximum luminance value in each row.

        In this case, the higher the resolution of the sensor, and the faster the camera shooting speed, the more accurately the shape of the object can be measured (that is, the larger the m according to FIG. 2, the more accurate the height value of the object is, The larger the better the dividing ability of the object in the y direction, and the faster the shooting speed, the better the dividing ability of the object in the x direction). However, the shooting speed of the camera has its own limitations, and even if the camera shoots at a high speed, it does not have meaning unless an external processor can process at a sufficient speed. As the resolution of the sensor increases, the number of pixels to be processed by an external processor increases, which makes it difficult to select freely. In addition, when three-dimensional shape measurement of a large number of objects is required, the work efficiency can be improved by increasing the moving speed of the moving stage, but in this case, the recording speed of the camera must also be increased, thereby increasing the amount of data transmitted to the external processor. Done.

       As a result, the precise measurement and work efficiency of the object are determined by the performance of the external processor, and thus the performance of the processor is limited, and thus, a fundamental method for replacing it is required.

The main object of the present invention is to provide a three-dimensional shape measuring camera that can reduce the amount of data to be processed by an external processor.

       Another object of the present invention is to provide a three-dimensional shape measuring camera that can process the luminance value obtained by the pixel array of the image sensor at a higher speed.

       Still another object of the present invention is to provide a camera for three-dimensional shape measurement, which can more economically achieve the processing speed improvement of the luminance value obtained by the pixel array of the image sensor.

Still another object of the present invention is to provide a three-dimensional shape measuring camera that can more efficiently process three-dimensional image measurement for a plurality of objects.

       The above and other objects of the present invention can be achieved by the present invention described below.

Summary of the Invention

A first feature of the present invention is to configure a comparison circuit inside a three-dimensional shape measuring camera to significantly reduce the amount of data transmitted to an external processor, thereby achieving a reduction in transmission time and a reduction in processing time of an external processor. will be. That is, the three-dimensional image measuring camera according to the present invention is a comparison circuit for obtaining the maximum value among the luminance values output from the digital image sensor and the maximum luminance value memory, and the maximum luminance value for newly storing the maximum value obtained by the comparison circuit. Memory and a maximum luminance position value memory for storing the position of the maximum value obtained by the comparison circuit, so that only data stored in the maximum luminance position value memory is transmitted to an external processor (corresponding to claim 1). .

A second feature of the present invention is that the three-dimensional shape measuring camera according to the first feature further includes an image memory for storing an image for one frame photographed by the digital image sensor. Through this, the operator can easily acquire the image information for the initial setting, etc., and at the same time, the operator can directly observe the image information on the frame currently being photographed by the camera (corresponding to claim 2).

According to a third aspect of the present invention, a comparison circuit of a camera according to the first aspect obtains a luminance value having a maximum size in units of each row of the pixel array, and the control unit obtains a maximum size in units of each row. And store the values of the columns of the pixel array corresponding to the luminous intensity values, respectively, in the maximum luminous intensity value memory. That is, the position having the maximum value for each pixel of DIS corresponds to the height at the specific y position of the object, so that the value of the column of the maximum value (that is, which column) is directly corresponded to the height value. (Corresponds to claim 3).

According to a fourth aspect of the present invention, the maximum luminance position value memory of the camera according to the first aspect includes a first maximum luminance position value memory and a second maximum luminance position value memory, wherein the maximum luminance is measured in units of each row of the pixel array. If the value is one, the position of the maximum luminous intensity value is equally stored in the first and second maximum luminous intensity position values memory, and the maximum luminous intensity value is stored in units of each row of the pixel array. In the case of a plurality, the initial position of the maximum luminance value is stored in the first maximum luminance position value memory and the final position of the maximum luminance value is stored in the second maximum luminance position value memory. Accordingly, when the maximum luminance value for a particular row exceeds a preset pixel recognition threshold, the same luminance value exists at a plurality of points. In this case, information about the positions of the two endpoints may be stored in the first maximum luminance value memory. After storing each in the second maximum brightness value memory, the position of the maximum brightness value can be determined by interpreting that it has a maximum value at an intermediate point later (corresponding to claim 4).

The fifth aspect of the present invention is to construct a comparison circuit inside a three-dimensional shape measurement camera to significantly reduce the amount of data transmitted to an external processor to achieve a reduction in transmission time and a reduction in processing time of an external processor. To provide a way. That is, a pixel array (n × m) in which slit light is reflected after being scanned on an object is formed, r (r is an integer of 1 or more) ADCs for AD conversion of luminance values input to the respective pixels, and are converted from the ADCs. Taking an object through an image sensor having s (s is an integer greater than or equal to) output ports for outputting a luminance value, and measuring the three-dimensional shape of the object by analyzing information output through the image sensor A method comprising: outputting s of luminous intensity values for each pixel in rows in a predetermined order; A maximum value is obtained from the outputted s intensity values and the luminosity values stored in the maximal intensity value memory (the first predetermined value is stored) through a comparison circuit and newly stored in the maximal intensity value memory; At the same time storing the value of the column of pixels having the maximum luminance value in the maximum luminance position value memory and repeating the above steps for every row of the pixel array; And measuring the shape of the object by analyzing m position values stored in the maximum luminance position value memory; The maximum brightness value memory, the maximum brightness position value memory, and the comparison circuit are provided in the camera (corresponding to claim 5).

Detailed Description of the Invention

       Figure 3 is a block diagram showing the operating state of the digital image sensor unit (hereinafter referred to as "DIS") in accordance with the present invention. The DIS is n x m image of the slit light reflected from the object 520 (this In the drawing, the pixel array 110 having the pixels 111 of 1,280 × 1,024 = 1,310,720, and the luminance values (which may include concepts such as color information in addition to the luminance values) acquired at each pixel are used for AD conversion. At least one ADC 120, an ADC memory 130 for storing the brightness value converted by the ADC, at least one output port 140 for outputting the brightness value stored in the ADC memory, and the pixel array , An ADC, an ADC memory, and an output port for controlling the output port 300. The DIS is generally configured in the form of a single chip, wherein the controller is an on-chip controller in hardware. ) And off-chip cont roller).

       Looking at the above configuration according to the present invention in more detail as follows. The ADCs are provided one by one in columns (hence 1280), so that the control unit 300 converts the luminance values of the charges charged for each row. That is, the input values of all the pixels (ie, 1280) in a specific row are transmitted to the ADC 131 corresponding to each column, and then AD converted. At this time, the converted value is stored in the ADC register 130 and backed up to the output register 131 so that the AD conversion for the next row on the pixel array can be continuously performed. The data stored in the output register 132 is transmitted to the outside through the output port 140 according to the signal of the controller 300.

       In the DIS according to this figure, the output port may be plural, and accordingly, the number of data output from the DIS at one time is determined. Preferably, the number of output ports is 10 (of course, an external application corresponding to the output port will also need 10 input ports). In other words, luminance values of 10 pixels are simultaneously output to the DIS.

       Figure 4 (A) is a schematic configuration diagram of one embodiment of a shape measuring camera having a comparison circuit according to the present invention, Figure 4 (B) is a schematic configuration diagram of another embodiment, and Figure 4 (C) is a schematic block diagram of another embodiment. The camera for measuring a three-dimensional shape according to FIG. 4A obtains a maximum value among the luminance values stored in the DIS 100, the luminance values output from the DIS, and the maximum luminance value memory described below. A maximum luminance value memory 430 for storing a comparison circuit 200, a maximum value obtained by the comparison circuit, and a maximum luminance position value memory 420 for storing positions of the maximum values obtained by the comparison circuit; And a controller 300 that controls the operation of the DIS and the comparison circuit, obtains the position of the maximum value obtained by the comparison circuit, and stores the calculated position in the maximum luminance position value memory.

       It is responsible for finding the maximum value among the luminous intensity values for ten pixels and the luminous intensity values stored in the maximum luminous value memory at the same time from the ADC output register 132 in which the AD converted luminous intensity values are stored for each row on the pixel array 110. It is the comparison circuit 200 that is in charge. The maximum value among the eleven luminance values is newly stored in the maximum luminance value memory 430. At the same time, information on the position value of the maximum value is stored in the maximum luminance position value memory 420. The maximum luminance position value is actually a value of a column of the corresponding pixel, i.e., the controller determines which column from the reference point the pixel having the maximum luminance value is located.

       This process is performed row by row. When there are 1280 columns, the above process is repeated 128 times. The maximum brightness value memory has an initial value (preferably a minimum value that can be detected by the slit light through the sensor.) If the slit light incident on a specific row is not properly detected, the maximum brightness in the row It may be desirable to prevent the position value from being taken into consideration when measuring the shape of the object.For example, the maximum luminance position value may be set to -1 as an initial value. After the operation is completed, it is set back to the initial value.

       If the above process is performed for all rows (that is, repeated 1024 times), data (i.e., 1280 positional information) for the point having the maximum luminance in all the rows can be obtained.

       4B is another specific example of the three-dimensional camera according to the present invention. The maximum brightness value memory 430 is configured to separately store the maximum brightness value in each row. This has the advantage that it is possible to know the information on the position having the maximum luminous intensity value in each row as well as what is the luminous intensity value at this time. As such, when the maximum luminance value of the corresponding row is known, the initial value of the maximum luminance position value memory is set to a value equal to -1 in case the slit light is not properly detected in a specific row. Does not require.

       Fig. 4C is another embodiment of the three-dimensional shape camera according to the present invention, wherein the maximum luminous intensity position value memory is composed of a first maximum luminous intensity position value memory 421 and a second maximum luminous intensity position value memory 422. will be. This assumes a case where a plurality of maximum luminance values appear in units of each row of the pixel array 110. That is, when the intensity of slit light input to each pixel exceeds a threshold that can be recognized by the pixel, it has the same maximum value for the columns belonging to the excess portion. In this case, if we know the value of the column corresponding to the start of the same maximum value and the value of the column corresponding to the end of the same maximum value, we can assume that the part of the center actually has the maximum value. The initial position of the value is stored in the first maximum luminance position value memory and the final position of the maximum luminance value is stored in the second maximum luminance position value memory. However, in this case, when there is one maximum luminance value for each row, the position of the maximum luminance value may be stored in the first maximum luminance position value memory or the same position value may be stored in the two memories. have.

              5 is a flowchart schematically illustrating a process of measuring a three-dimensional shape of an object through a camera according to the present invention. When the slit light reflected from the object 520 is incident on the pixel array 110 and charges are accumulated in each pixel 111 (S100), the resultant value is AD converted through the ADC 120 (S200). It is output through the output port 140.

       The luminance values for each pixel are simultaneously output as many as the number of output ports, and the position of the pixel at which the luminance values are maximum in units of rows is obtained (S300). The position value of the maximum luminance thus determined is stored in the maximum luminance position value memory 420 (S400), and the shape of the object for one frame is obtained by repeating this process for all rows.

        FIG. 6 is a flowchart more specifically describing steps S300 and S400 in FIG. Luminous intensity data for each pixel stored in the ADC memory are outputted simultaneously through 10 output ports, 10 of which are the first 10 luminous intensity data of the first row from the reference point and the initial value stored in the maximum luminous intensity memory. The maximum value is obtained and stored again in the maximum luminance value memory (S310 and S320). At the same time, a position value for the maximum luminance value is obtained and stored in the maximum luminance position value memory (S410), wherein the position value corresponds to the value of the column COLUMN of the pixel having the maximum luminance value. After the steps S310 and S410 are repeated for all the pixels in the first row, the maximum luminous intensity value is stored in the maximum luminous intensity value among all the pixels in the first row, and the first luminous intensity value memory is stored first. The position value of the pixel having the maximum luminance value among all the pixels in the row is stored.

       Further, when the steps S310, S410, and S420 are performed for all remaining rows, the position value data (1024 pieces) whose luminance values are the maximum for all the rows (1024 pieces) in the maximum luminance position value memory. Will be stored. As described above, since the 1024 position value data correspond to the height value of the cross section cut in the object y direction (height value for each point divided into 1024 points), the shape of the object is finally measured.

       Similarly, while moving the object in the x direction at a predetermined speed, the camera photographs the object at a predetermined speed, and analyzing the luminance value data for each frame as described above enables measuring the shape of the entire object.

The present invention can reduce the amount of data to be processed by the external processor to process the luminance value obtained by the pixel array of the image sensor at a higher speed, and also to achieve this processing speed more economically. In addition, there is an effect of providing a three-dimensional image measuring camera that can more efficiently process the three-dimensional image measurement for a plurality of objects.

Simple modifications and variations of the present invention can be easily made by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (5)

In the camera for measuring the three-dimensional shape of the object through the slit light scanning method,       A digital image sensor unit (hereinafter referred to as "DIS") having a pixel array composed of n x m pixels and outputting the luminance value of the slit light that is scanned and reflected on the object and formed on each pixel in units of pixels. ;       A comparison circuit for obtaining a maximum value among the luminance values output from the DIS and the values stored in the maximum luminance value memory;       A maximum luminance value memory for storing the maximum value obtained by the comparison circuit;       A maximum luminance position value memory for storing a position of the maximum value obtained by the comparison circuit; And       A control unit which controls the operation of the DIS and the comparison circuit, obtains the position of the maximum value obtained by the comparison circuit, and stores the calculated position in the maximum luminance position value memory;       3D shape measuring camera comprising a. The 3D shape measuring camera of claim 1, further comprising an image memory configured to store an image of an object for one frame output from the DIS. The display device of claim 1, wherein the comparison circuit obtains a luminance value having a maximum size in each row of the pixel array, and the controller corresponds to a luminance value having a maximum size in each row. And storing the column values of the pixel array in the maximum luminance position value memory, respectively. The memory device of claim 1, wherein the maximum luminance position value memory comprises a first maximum luminance position value memory and a second maximum luminance position value memory.        When the maximum luminance value is one unit for each row of the pixel array, the position of the maximum luminance value is stored in the first maximum luminance position value memory.        In the case where there is a plurality of maximum luminance values for each row of the pixel array, the initial position of the maximum luminance value is stored in the first maximum luminance position value memory and the final position of the maximum luminance value is the second maximum luminance. 3D shape measurement camera, characterized in that stored in the position value memory. A pixel array (n × m) in which the slit light reflected by the object is imaged and then reflected, r (r is an integer of 1 or more) ADCs for AD conversion of the luminance values input to the respective pixels, and the luminances converted from the ADCs In the method of measuring the three-dimensional shape of the object by photographing the object through a camera having s (s is an integer of 1 or more) for outputting the value, and by analyzing the information obtained through the camera ,         Outputting the luminosity values for the respective pixels row by row in a predetermined order (step S10);       The maximum value among the brightness values stored in the output s intensity values and the maximum intensity value memory (the first predetermined value is stored) is obtained through a comparison circuit, and is newly stored in the maximum intensity value memory. Store the value of the column of pixels having the luminance value in the maximum luminance position value memory (step S20);       The steps S10 and S20 are repeated for every row of the pixel array (step S30); And       Measuring the shape of the object by analyzing m position values stored in the maximum luminance position value memory (step S40);       And the maximum brightness value memory, the maximum brightness position value memory, and the comparison circuit are integrally provided in the camera.

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