Information processing apparatus and method for processing information

Abstract

To provide an information processing apparatus and a method for processing information capable of improving the accuracy of the result of calculating the moving distance of a workpiece compared with an existing apparatus and an existing method.SOLUTION: An information processing apparatus (100) includes: an optical information acquisition unit (10) for acquiring one-dimensional optical information along a second direction (D2) of a workpiece (W1); a correlation value calculation unit (20) for calculating a correlation value indicating the correlation between optical information acquired at two different times; and an angle estimation unit (30) for estimating the angle formed between a first direction (D1) and the second direction (D2) on the basis of the correlation value calculated by the correlation value calculation unit (20).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an information processing device and an information processing method. [Background technology]

[0002] Conventionally, a displacement meter has been disclosed that measures the displacement (movement distance) of a measurement object (workpiece) transported by a transport device based on one-dimensional information from a line sensor that detects reflected light from the measurement object (workpiece) (see, for example, Patent Document 1). This displacement meter detects extreme values ​​(peaks) of the cross-correlation function of multiple images detected at different times by the line sensor, and calculates the amount of displacement of the measurement object based on the detection results. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-170550 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when acquiring information about the surface of a moving workpiece as one-dimensional optical information and calculating the movement distance of the workpiece based on the correlation of the acquired multiple pieces of one-dimensional optical information, it is difficult to make the movement direction of the workpiece perfectly parallel to the direction in which the one-dimensional optical information is acquired. Furthermore, if the movement direction of the workpiece and the direction in which the one-dimensional optical information is acquired are not parallel, the calculation result of the movement distance contains an error corresponding to the angle between the movement direction of the workpiece and the direction in which the one-dimensional optical information is acquired, which poses a problem that it is difficult to improve the accuracy of the calculation result of the movement distance.

[0005] The present disclosure was made in response to the recognition of the above-mentioned problems, and aims to provide an information processing device and an information processing method that can improve the accuracy of the calculation results of the workpiece movement distance compared to conventional methods. [Means for solving the problem]

[0006] The information processing device according to the present disclosure is characterized by including an optical information acquisition unit that acquires one-dimensional optical information along a second direction of a workpiece based on light from the workpiece moving in a first direction, a correlation value calculation unit that calculates a correlation value indicating the correlation between the optical information acquired by the optical information acquisition unit at two different times, and an angle estimation unit that estimates the angle between the first direction and the second direction based on the correlation value calculated by the correlation value calculation unit. [Effects of the Invention]

[0007] According to the present disclosure, the accuracy of the calculation results of the movement distance of the workpiece can be improved compared to the conventional art. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing a schematic configuration of an information processing system according to a first embodiment. [Figure 2] 1 is a schematic diagram showing an optical system according to a first embodiment. [Figure 3] 3 is a schematic diagram showing optical information acquired by the optical sensor according to the first embodiment when the movement direction and the measurement direction are parallel, as viewed from a direction perpendicular to the surface of the workpiece. FIG. [Figure 4] 4 is a graph showing optical information acquired by the information processing device according to the first embodiment. [Figure 5] 1 is a diagram illustrating an example of a hardware configuration of an information processing device according to a first embodiment. [Figure 6] 1 is a diagram illustrating an example of a hardware configuration of an information processing device according to a first embodiment. [Figure 7] 4 is a flowchart showing a regression function calculation process performed by the information processing device according to the first embodiment. [Figure 8] 10 is a graph showing the relationship between the correlation value calculated by the information processing device according to the first embodiment and the amount of deviation of optical information. [Figure 9]4 is a graph showing a regression function calculated by the information processing device according to the first embodiment. [Figure 10] 1 is a schematic diagram showing optical information acquired by the information processing device according to the first embodiment in a state where the movement direction and the measurement direction are not parallel, as viewed from a direction perpendicular to the surface of the workpiece. [Figure 11] 4 is a flowchart showing a travel distance calculation process performed by the information processing device according to the first embodiment. [Figure 12] 10 is a flowchart showing an angle estimation process performed by an information processing device according to a modification of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Embodiment 1 First, the configuration of an information processing system according to the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic diagram illustrating the information processing system according to the first embodiment. The information processing system according to the first embodiment is a system for measuring the movement distance of a workpiece W1 by calculating the movement distance of the workpiece W1 based on optical information from an optical sensor S1. For example, the workpiece W1, which is the object to be measured, is formed in a sheet shape and moves in one direction as the roll rotates while being unwound or wound into a roll. As shown in FIG. 1, the information processing system according to the first embodiment includes an optical system including a light source LT1 and an optical sensor S1, and an information processing device 100, which are electrically connected by wire or wirelessly so that information can be communicated from the optical sensor S1 to the information processing device 100.

[0010] FIG. 2 is a schematic diagram showing an optical system according to the first embodiment. As shown in FIG. 2, the optical system according to the first embodiment includes, for example, a light source LT1, a condenser lens OP1, an imaging lens OP2, and an optical sensor S1. The light source LT1 is configured, for example, by an LED (Light-Emitting Diode) or a halogen lamp, and emits light when supplied with power. The condenser lens OP1 is configured by a simple lens or a compound lens, and condenses light from the light source LT1 onto the workpiece W1 to illuminate the surface W1a of the workpiece W1. The imaging lens OP2 is configured by a simple lens or a compound lens, and focuses light reflected from the surface W1a of the workpiece W1 onto the optical sensor S1. For example, the imaging lens OP2 is configured by a telecentric lens that focuses light reflected from the surface W1a of the workpiece W1 onto the optical sensor S1.

[0011] The optical sensor S1 is configured by a one-dimensional image sensor in which N imaging elements, numbered 1 to N (for example, N is a natural number equal to or greater than 2), are arranged. For example, the N imaging elements are linearly arranged along a specific direction. The optical sensor S1 acquires image data, which is one-dimensional optical information with a number of pixels corresponding to the number of imaging elements, based on, for example, reflected light from the surface W1a of the workpiece W1 moving in the movement direction D1. In other words, the optical sensor S1 acquires one-dimensional image data with a number of pixels corresponding to the number of imaging elements by capturing an image of the workpiece W1 moving in the movement direction D1. The optical sensor S1 acquires one-dimensional image data corresponding to the light receiving intensity of each imaging element at a specific time interval (imaging interval) and outputs the acquired image data to the information processing device 100. Note that in the first embodiment, the direction of the one-dimensional image data acquired by the optical sensor S1 is also referred to as a measurement direction D2. Also, in the first embodiment, the movement direction D1 is also referred to as a first direction, and the measurement direction D2 is also referred to as a second direction.

[0012] Next, the configuration of the information processing device 100 will be described with reference to Figures 1 to 4. As shown in Figure 1, the information processing device 100 includes an optical information acquisition unit 10, a correlation value calculation unit 20, an angle estimation unit 30, a travel distance calculation unit 40, and a storage unit 50.

[0013] The optical information acquisition unit 10 acquires one-dimensional image data of the workpiece W1 along the measurement direction D2, based on information from the optical sensor S1. In other words, the optical information acquisition unit 10 acquires one-dimensional image data of the workpiece W1 along the measurement direction D2, based on light from the workpiece W1 moving in the movement direction D1.

[0014] 3 is a schematic diagram showing image data A1 and A2 acquired by the optical sensor S1 according to embodiment 1 when the movement direction D1 and the measurement direction D2 are parallel, as viewed from a direction perpendicular to the surface W1a of the workpiece W1. For example, when image data is acquired by the optical information acquisition unit 10 at a first time t1 and a second time t2 that is later than the first time t1, the condition under which the image data A1 acquired by the optical information acquisition unit 10 at the first time t1 and the image data A2 acquired at the second time t2 partially overlap each other (the hatched portion in FIG. 3) at a distance L2 is expressed by the following formula (1). In formula (1), v1 represents the movement speed of the workpiece W1, and L1 represents the distance on the surface W1a of the workpiece W1 at which the image data is acquired by the optical information acquisition unit 10. L1>v1×(t2-t1) (1)

[0015] Furthermore, since the movement distance Lm of the workpiece W1 in the movement direction D1 between time t1 and time t2 is equal to the difference between the distance L1 and the overlap distance L2 of the image data A1 and the image data A2, Lm is calculated using the following formula (2). Lm = L1 - L2 (2)

[0016] FIG. 4 is a graph showing image data A1 and A2 acquired by the information processing device 100 according to the first embodiment. In FIG. 4, the horizontal axis represents the numbers of the image sensors in the movement direction D1, from No. 1 at the rear end to No. N at the front end, and the vertical axis represents the light receiving intensity of each image sensor. For example, when the optical sensor S1 captures images of a workpiece W1 moving in the movement direction D1 at times t1 and t2, a specific position of the workpiece W1 captured by the Nth image sensor at time t1 is captured by the image sensor closer to No. 1 at time t2. As a result, as shown in FIG. 4, the waveform of the image data A2 acquired by the optical information acquisition unit 10 at time t2 is a waveform obtained by shifting the waveform of the image data A1 acquired by the optical information acquisition unit 10 at time t1 by an amount corresponding to the distance traveled in the movement direction D1 of the workpiece W1 between time t1 and time t2.

[0017] Therefore, by calculating a correlation value indicating the correlation between two waveforms of image data acquired at two different times and calculating the distance between the two waveforms where the correlation value is highest, the movement distance of the work W1 in the movement direction D1 from time t1 to time t2 can be calculated.

[0018] The correlation value calculation unit 20 calculates a correlation value indicating the correlation between the two pieces of image data by comparing the image data acquired at two different times by the optical information acquisition unit 10. For example, when the image data A1 and image data A2 shown in Fig. 4 are acquired by the optical information acquisition unit 10, the correlation value calculation unit 20 calculates a correlation value indicating the correlation between the image data A1 and image data A2 by phase-only correlation.

[0019] For example, if the image sensor number is x, the waveform representing image data A1 is f1(x), and the waveform representing image data A2 is f2(x), the correlation value calculation unit 20 first calculates Fourier image data F1(u) and F2(u) by performing a discrete Fourier transform on f1(x) and f2(x), respectively. Note that in F1(u) and F2(u), u represents the spatial frequency. Furthermore, the correlation value calculation unit 20 calculates composite Fourier image data F3(u) by combining F1(u) and F2(u) using the following formula (2). Note that in formula (3), "*" represents the complex conjugate. F3(u)=F1*(u)·F2(u) ···(3)

[0020] Furthermore, the correlation value calculation unit 20 performs phase limitation processing on F3(u) to calculate Fourier image data F4(u) using the following formula (4): As a result, the amplitude of all frequencies of F3(u) is set to 1, and composite Fourier image data F4(u) containing only phase is obtained. F4(u)=F3(u) / |F3(u)| (4)

[0021] Furthermore, the correlation value calculation unit 20 performs an inverse Fourier transform on F4(u) to calculate the composite inverse Fourier image data f4(x). In the first embodiment, f4(x) constitutes a correlation value indicating the correlation between the image data acquired by the optical information acquisition unit 10 at two different times.

[0022] The movement distance calculation unit 40 calculates the movement distance of the workpiece W1 in the movement direction D1 based on the correlation value calculated by the correlation value calculation unit 20. For example, when the movement direction D1 and the measurement direction D2 are parallel, the movement distance calculation unit 40 calculates the movement distance of the workpiece W1 in the movement direction D1 based on f4(x) calculated by the correlation value calculation unit 20 using the following procedure. The movement distance calculation unit 40 first extracts x at which the waveform of f4(x) shows a peak based on f4(x) calculated by the correlation value calculation unit 20. Note that x at which the waveform of f4(x) shows a peak is a value that represents the amount of deviation between the image data A1 and the image data A2 caused by the movement of the workpiece W1 between time t1 and time t2, expressed as a multiple of the distance (pixel pitch) between the imaging elements. Furthermore, the movement distance calculation unit 40 calculates the movement distance Lm of the workpiece W1 between time t1 and time t2 based on the extracted x using the following equation (5): In the formula (5), p represents the distance between the imaging elements, and β represents the magnification (lateral magnification) of the imaging lens OP2. Lm=x×p / β (5)

[0023] The angle estimation unit 30 estimates the angle between the movement direction D1 and the measurement direction D2 based on the correlation value calculated by the correlation value calculation unit 20. Generally, when measuring the movement distance of a workpiece W1 based on the correlation of one-dimensional optical information, it is desirable to measure the movement distance while the movement direction of the workpiece and the measurement direction of the sensor are parallel. However, in reality, it is difficult to make the movement direction of the workpiece and the measurement direction of the sensor perfectly parallel. Furthermore, if the movement direction of the workpiece and the measurement direction are not parallel, the calculation result of the movement distance of the workpiece W1 contains an error corresponding to the angle between the movement direction of the workpiece and the measurement direction. Therefore, the information processing device 100 in the first embodiment calculates the movement distance of the workpiece W1 based on the angle between the movement direction D1 and the measurement direction D2 estimated by the angle estimation unit 30, thereby improving the accuracy of the calculation result of the movement distance of the workpiece W1 compared to conventional methods. Details of the angle estimation unit 30 will be described later.

[0024] The storage unit 50 stores information used when the information processing device 100 performs each process and information indicating the results of each process. The storage unit 50 stores, for example, image data acquired by the optical information acquisition unit 10, functions indicating each waveform calculated by the correlation value calculation unit 20, results of processing by the angle estimation unit 30, results of processing by the travel distance calculation unit 40, and various setting values ​​used when each component of the information processing device 100 performs a process. When each component of the information processing device 100 performs a process, it references and reads information stored in the storage unit 50 as necessary, and stores the results of each process in the storage unit 50.

[0025] Next, the hardware configuration of the information processing device 100 will be described with reference to FIGS. 5 and 6. FIG. 5 is a block diagram showing an example of the hardware configuration of the information processing device 100 according to the first embodiment, and FIG. 6 is a block diagram showing an example of a hardware configuration of the information processing device 100 according to the first embodiment, which is different from that shown in FIG. 5. For example, as shown in FIG. 5, the information processing device 100 includes a processor 100a, a memory 100b, and an I / O port 100c, and is configured so that the processor 100a reads and executes a program stored in the memory 100b. The memory 100b is configured, for example, by a non-volatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, an EPROM, or an EEPROM, or a combination thereof. The memory 100b may also be a magnetic disk, a flexible disk, an optical disk, a compact disk, a minidisk, a DVD, or the like. The memory 100b may also be an HDD or an SSD.

[0026] 6, the information processing device 100 includes a processing circuit 100d and an I / O port 100c, which are dedicated hardware. The processing circuit 100d is configured, for example, by a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, a system LSI (Large-Scale Integration), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. Each function of the information processing device 100 is realized by the processor 100a or the processing circuit 100d, which is dedicated hardware, executing a program that is software, firmware, or a combination of software and firmware. The information processing device 100 may also include hardware other than those described above, such as a hardware timer.

[0027] Next, processing performed by the information processing device 100 will be described with reference to FIGS. 1 and 7 to 11. FIG. 7 is a flowchart showing a regression function calculation process performed by the information processing device 100 according to the first embodiment. The regression function calculation process performed by the information processing device 100 is a process in which, when the moving direction D1 and the measurement direction D2 are not parallel, the angle estimation unit 30 calculates a first regression function and a second regression function based on a correlation value between image data. The first regression function and the second regression function are used to estimate the angle between the moving direction D1 and the measurement direction D2 using the angle estimation unit 30 based on a correlation value between image data. A worker who intends to measure the moving distance of the workpiece W1 using the information processing device 100 starts the regression function calculation process in the information processing device 100, for example, in a state in which the optical sensor S1 is positioned so that the angle θ1 between the moving direction D1 and the measurement direction D2 is as small as possible. Note that in the first embodiment, the angle θ1 is also referred to as a first angle. In the first embodiment, the first regression function and the second regression function constitute a first function and a second function.

[0028] 7, when the information processing device 100 starts the regression function calculation process, it first acquires reference optical information (step ST01). In this process, the information processing device 100 acquires, by the optical information acquisition unit 10, image data as reference optical information, which is optical information that serves as a reference when the correlation value calculation unit 20 calculates a correlation value.

[0029] After performing the process of step ST01, the information processing device 100 acquires measured optical information (step ST02). In this process, when the correlation value calculation unit 20 calculates the correlation value, the information processing device 100 acquires, by the optical information acquisition unit 10, image data as measured optical information, which is optical information to be compared with the reference optical information acquired in the process of step ST01. Note that in this process, the information processing device 100 acquires new image data as measured optical information acquired by the optical sensor S1 at a predetermined specific time interval after the image data as the reference optical information acquired in the process of step ST01 is acquired by the optical sensor S1.

[0030] After performing the process of step ST02, the information processing device 100 calculates a correlation value between the reference optical information and the immediately preceding measured optical information (step ST03). In this process, the information processing device 100 uses the correlation value calculation unit 20 to calculate a correlation value between the image data acquired in the process of step ST01 and the image data acquired in the process of the immediately preceding step ST02, which is used to calculate the first regression function.

[0031] After performing the processing of step ST03, the information processing device 100 calculates the movement distance of the workpiece W1 in the measurement direction D2 (step ST04). In this processing, the information processing device 100 calculates the movement distance of the workpiece W1 in the measurement direction D2 when the angle formed between the movement direction D1 and the measurement direction D2 is the first angle θ1, using the above-mentioned formula (5), based on, for example, the amount of deviation between the image data as the reference optical information and the image data as the measurement optical information obtained from the correlation value calculated in the processing of step ST03, the distance between the image sensors, and the magnification of the imaging lens.

[0032] 8 is a graph showing the relationship between the correlation value f4(x) calculated by the information processing device 100 according to embodiment 1 and the amount of deviation x of image data as optical information. In the processing of step ST04, the information processing device 100 extracts x at which the waveform of f4(x) shows a peak, thereby obtaining the amount of deviation between the image data A1 and the image data A2 caused by the movement of the workpiece W1 between time t1 and time t2, and calculates the movement distance of the workpiece W1 in the measurement direction D2 based on the amount of deviation between the image data A1 and the image data A2.

[0033] After performing the process of step ST04, the information processing device 100 determines whether the number of times to end has been reached (step ST05). In this process, the information processing device 100 determines whether a sufficient number of correlation values ​​have been calculated to be used for calculating a regression function by regression analysis in a state where the angle between the moving direction D1 and the measurement direction D2 is the first angle θ1.

[0034] In the process of step ST05, if the termination count has not been reached (NO in step ST05), the information processing device 100 returns the process to step ST02 and acquires measured optical information for calculating a new correlation value. In this way, the information processing device 100 repeats the processes from step ST02 to step ST05 multiple times to calculate each correlation value between the image data as the reference optical information and the multiple pieces of image data as the measured optical information, and the movement distance of the workpiece W1 in the measurement direction D2 corresponding to each correlation value, when the angle formed between the movement direction D1 and the measurement direction D2 is the first angle θ1. Note that the information processing device 100 repeats the processes from step ST02 to step ST05 multiple times to acquire multiple pieces of image data from the optical sensor S1 at a predetermined specific time interval.

[0035] In the process of step ST05, if the termination count is reached (YES in step ST05), the information processing device 100 calculates a regression function (step ST06). In this process, the information processing device 100 calculates the regression function, which is a regression model, by regression analysis based on the multiple correlation values ​​calculated in the processes from step ST02 to step ST05 and the movement distance of the workpiece W1 in the measurement direction D2 corresponding to each correlation value.

[0036] FIG. 9 is a graph showing a regression function calculated by the information processing device 100 according to the first embodiment. The information processing device 100 calculates f5 as a first regression function shown in FIG. 9 using the angle estimation unit 30 based on the results of repeating the processes from step ST02 to step ST05 multiple times. FIG. 9 shows the result of the information processing device 100 calculating the regression function f5 based on the results of repeating the processes from step ST02 to step ST05 seven times. For example, the information processing device 100 calculates the regression function f5 by linear regression analysis based on the results of repeating the processes from step ST02 to step ST05 multiple times. As shown in FIG. 9, the correlation value between the image data as the reference optical information and the image data as the measurement optical information decreases depending on the amount of deviation in the measurement direction D2 between the image data as the reference optical information and the image data as the measurement optical information. In other words, the correlation value between the image data as the reference optical information and the image data as the measurement optical information decreases depending on the movement distance of the workpiece W1 after the image data as the reference optical information is acquired.

[0037] After performing the process of step ST06, the information processing device 100 stores the calculated regression function as a first regression function (step ST07). In this process, the information processing device 100 stores the first angle θ1 between the movement direction D1 and the measurement direction D2 when performing the processes of steps ST01 to ST05 in the storage unit 50 together with the first regression function. The information processing device 100 may be configured to acquire the value of the first angle θ1 based on an input operation by an operator to an input device (not shown) electrically connected to the information processing device 100, or may be configured to acquire the value of the first angle θ1 based on an input signal from an angle sensor (not shown) electrically connected to the information processing device 100 and detecting the angle between the movement direction D1 and the measurement direction D2.

[0038] After the information processing device 100 has performed the processing of step ST07, the worker causes the information processing device 100 to start the processing of step ST08 and subsequent steps in a state in which the optical sensor S1 is positioned so that the angle between the movement direction D1 and the measurement direction D2 is an angle θ2 different from the angle formed when the processing of steps ST01 to ST05 has been performed. For example, after the information processing device 100 has performed the processing of step ST07, the worker causes the information processing device 100 to start the processing of step ST08 and subsequent steps in a state in which the optical sensor S1 is positioned so that the angle between the movement direction D1 and the measurement direction D2 is an angle that is larger than the angle formed when the processing of steps ST01 to ST05 has been performed but is less than 90°. In the first embodiment, the angle θ2 is also referred to as a second angle.

[0039] 10 is a schematic diagram viewed from a direction perpendicular to the surface W1a of the workpiece W1, showing image data A3 and A4 acquired by the information processing device 100 according to embodiment 1 in a state in which the movement direction D1 and the measurement direction D2 are not parallel. For example, if the optical information acquisition unit 10 acquires image data at a first time t3 and a second time t4 that is later than the first time t3 in a state in which the angle formed between the movement direction D1 and the measurement direction D2 is greater than 0, the image data A3 acquired by the optical information acquisition unit 10 at the first time t3 and the image data A4 acquired at the second time t4 will partially overlap each other (the hatched portion in FIG. 10).

[0040] When the moving direction D1 and the measurement direction D2 are not parallel, the image data A3 and A4 are shifted in a direction intersecting the moving direction D1, so the larger the angle between the moving direction D1 and the measurement direction D2, the smaller the correlation value between the image data A3 and A4 with respect to the amount of shift in the measurement direction D2 between the image data A3 and A4. In other words, when the moving direction D1 and the measurement direction D2 are not parallel, the larger the angle between the moving direction D1 and the measurement direction D2, the greater the slope of the regression function shown in Figure 9. Therefore, it is possible to estimate the angle between the moving direction D1 and the measurement direction D2 based on regression functions calculated for two different angles between the moving direction D1 and the measurement direction D2.

[0041] After performing the process of step ST07, the information processing device 100 acquires reference optical information (step ST08). In this process, the information processing device 100 acquires image data as the reference optical information in a state where the optical sensor S1 is positioned at an angle different from the state in which the processes of steps ST01 to ST07 are performed.

[0042] After performing the process of step ST08, the information processing device 100 acquires measured optical information (step ST09). In this process, when the correlation value calculation unit 20 calculates the correlation value, the information processing device 100 acquires, by the optical information acquisition unit 10, image data as measured optical information to be compared with the reference optical information acquired in the process of step ST08. Note that in this process, the information processing device 100 acquires new image data as measured optical information acquired by the optical sensor S1 at a predetermined specific time interval after the image data as the reference optical information acquired in the process of step ST08 is acquired by the optical sensor S1.

[0043] After performing the process of step ST09, the information processing device 100 calculates a correlation value between the reference optical information and the immediately preceding measured optical information (step ST10). In this process, the information processing device 100 uses the correlation value calculation unit 20 to calculate a correlation value between the image data acquired in the process of step ST08 and the image data acquired in the process of the immediately preceding step ST09, which is used to calculate the second regression function.

[0044] When the information processing device 100 performs the processing of step ST10, the position of the workpiece in the measurement direction is Calculating the moving distance (step ST11). In this process, the information processing device 100 calculates the moving distance of the workpiece W1 in the measurement direction D2 when the angle formed between the moving direction D1 and the measurement direction D2 is the second angle θ2, using the above-mentioned formula (5), based on, for example, the amount of deviation between the image data as the reference optical information and the image data as the measurement optical information obtained from the correlation value calculated in the process of step ST10, the distance between the image sensors, and the magnification of the imaging lens.

[0045] After performing the process of step ST11, the information processing device 100 determines whether the number of times to end has been reached (step ST12). In this process, the information processing device 100 determines whether a sufficient number of correlation values ​​have been calculated to be used for calculating a regression function by regression analysis in a state where the angle between the moving direction D1 and the measurement direction D2 is the second angle θ2.

[0046] In the process of step ST12, if the termination count has not been reached (NO in step ST12), the information processing device 100 returns the process to step ST09 and acquires new measured optical information. In this way, the information processing device 100 repeats the processes from step ST09 to step ST12 multiple times to calculate correlation values ​​between the image data as the reference optical information and the multiple pieces of image data as the measured optical information, and the movement distance of the workpiece W1 in the measurement direction D2 corresponding to each correlation value, when the angle formed between the movement direction D1 and the measurement direction D2 is the second angle θ2. Note that the information processing device 100 acquires multiple pieces of image data from the optical sensor S1 at a predetermined specific time interval by repeating the processes from step ST09 to step ST12 multiple times.

[0047] In the process of step ST12, if the termination count has been reached (YES in step ST12), the information processing device 100 calculates a regression function (step ST13). In this way, the information processing device 100 calculates f6 as the second regression function shown in Fig. 9 using the angle estimation unit 30 based on the results of repeating the processes from step ST09 to step ST12 multiple times. As shown in Fig. 9, it can be seen that the slope of f6 as the second regression function is larger than that of f5 as the first regression function.

[0048] After performing the process of step ST13, the information processing device 100 stores the calculated regression function as a second regression function (step ST14). In this process, the information processing device 100 stores the second angle θ2 formed between the movement direction D1 and the measurement direction D2 when performing the processes of steps ST09 to ST12 in the storage unit 50 together with the second regression function. The configuration by which the information processing device 100 acquires the value of the second angle θ2 is similar to the configuration by which the information processing device 100 acquires the value of the first angle θ1, and therefore description thereof will be omitted.

[0049] After performing the process of step ST14, the information processing device 100 ends the regression function calculation process.

[0050] 11 is a flowchart showing the movement distance calculation process performed by the information processing device 100 according to embodiment 1. The movement distance calculation process performed by the information processing device 100 is a process for calculating the movement distance of the workpiece W1 in the movement direction D1 based on the first regression function and the second regression function calculated in advance.

[0051] 11, when the information processing device 100 starts the movement distance calculation process, it first acquires reference optical information (step ST21). In this process, the information processing device 100 acquires image data as reference optical information using the optical information acquisition unit 10 in a state where the angle θ between the movement direction D1 and the measurement direction D2 is unknown.

[0052] After performing the process of step ST21, the information processing device 100 acquires first measured optical information (step ST22). In this process, the information processing device 100 acquires, by the optical information acquisition unit 10, image data as measured optical information, which is optical information to be compared with the reference optical information, when the correlation value calculation unit 20 calculates the correlation value. Note that in this process, the information processing device 100 acquires image data as the first measured optical information newly acquired by the optical sensor S1 at a predetermined specific time interval after the image data as the reference optical information is acquired by the optical sensor S1.

[0053] After performing the process of step ST22, the information processing device 100 calculates a first correlation value between the reference optical information and the first measured optical information (step ST23). In this process, the information processing device 100 uses the correlation value calculation unit 20 to calculate the first correlation value, which is the correlation value between the image data as the reference optical information and the image data as the first measured optical information acquired in the process of the immediately preceding step ST22.

[0054] After performing the processing of step ST23, the information processing device 100 calculates a first movement distance of the workpiece W1 in the measurement direction D2 (step ST24). In this processing, the information processing device 100 calculates the first movement distance, which is the movement distance of the workpiece W1 in the measurement direction D2 from the time when the image data as the reference optical information is acquired to the time when the image data as the first measured optical information is acquired. The method for calculating the first movement distance of the workpiece W1 in the measurement direction D2 is similar to the method for calculating the movement distance of the workpiece W1 in the regression function calculation processing, and therefore description thereof will be omitted.

[0055] After performing the process of step ST24, the information processing device 100 acquires second measured optical information (step ST25). In this process, the information processing device 100 acquires, by the optical information acquisition unit 10, image data as the second measured optical information, which is optical information to be compared with the reference optical information, when the correlation value calculation unit 20 calculates the correlation value. Note that in this process, the information processing device 100 acquires image data as the second measured optical information newly acquired by the optical sensor S1 at a predetermined specific time interval after the image data as the first measured optical information is acquired by the optical sensor S1.

[0056] After performing the process of step ST25, the information processing device 100 calculates a second correlation value between the reference optical information and the second measured optical information (step ST26). In this process, the information processing device 100 uses the correlation value calculation unit 20 to calculate the second correlation value, which is the correlation value between the image data as the reference optical information and the image data as the second measured optical information acquired in the process of the immediately preceding step ST25.

[0057] After performing the processing of step ST26, the information processing device 100 calculates a second movement distance of the workpiece W1 in the measurement direction D2 (step ST27). In this processing, the information processing device 100 calculates the second movement distance, which is the movement distance of the workpiece W1 in the measurement direction D2 from the time when the image data as the reference optical information is acquired to the time when the image data as the second measured optical information is acquired. The method for calculating the second movement distance of the workpiece W1 in the measurement direction D2 is similar to the method for calculating the movement distance of the workpiece W1 in the regression function calculation processing, and therefore description thereof will be omitted.

[0058] After performing the process of step ST24, the information processing device 100 calculates a third regression function (step ST28). In this process, the third regression function calculated by the information processing device 100 is a regression function calculated by regression analysis based on the first correlation value, the first movement distance, the second correlation value, and the second movement distance. For example, in this process, the information processing device 100 calculates the third regression function, which is a regression function, by linear regression analysis based on the first correlation value, the first movement distance, the second correlation value, and the second movement distance. Note that in the first embodiment, the third regression function constitutes the third function.

[0059] After performing the processing of step ST28, the information processing device 100 estimates the angle θ between the movement direction D1 of the workpiece W1 and the measurement direction D2 based on the first regression function, the second regression function, and the third regression function (step ST29). For example, in this processing, the information processing device 100 estimates the angle θ using the angle estimation unit 30 based on the ratio between the slope of each regression function and the angle between the movement direction D1 and the measurement direction D2 using the following formula (6). Note that in formula (6), θ1 represents the first angle between the movement direction D1 and the measurement direction D2 when the first regression function is calculated, θ2 represents the second angle between the movement direction D1 and the measurement direction D2 when the second regression function is calculated, a1 represents the slope of the first regression function, a2 represents the slope of the second regression function, and a3 represents the slope of the third regression function. In the first embodiment, the angle θ estimated in the processing of step ST29 is also referred to as the third angle. θ=((a3-a1) / (a2-a1))×(θ2-θ1)+θ1 ···(6)

[0060] It has been revealed through experiments that, while the first and second regression functions generally do not depend greatly on the type of workpiece W1, they change more specifically depending on the material, color, pattern, and state of minute surface irregularities of the workpiece W1. For this reason, the information processing device 100 stores average first and second regression functions calculated from a plurality of workpieces W1 in the storage unit 50 and uses them when performing the movement distance calculation process, but in order to obtain the third angle more accurately, it is desirable to calculate the first and second regression functions for each type of workpiece W1 or for each lot of workpiece W1 and store them in the storage unit 50, and use a first regression function and a second regression function appropriately selected from the plurality of first regression functions and second regression functions when performing the movement distance calculation process.

[0061] After performing the processing of step ST29, the information processing device 100 calculates the movement distance of the workpiece W1 in the movement direction D1 (step ST30). For example, based on the angle θ estimated in the processing of step ST29 and the movement distance Lm1 of the workpiece W1 in the measurement direction D2 calculated in step ST24, the information processing device 100 calculates the movement distance Lm2 of the workpiece W1 in the movement direction D1 from the time when the image data as the reference optical information is acquired to the time when the image data as the measurement optical information is acquired, using the following formula (7), and stores the calculation result in the storage unit 50. Lm2=Lm1 / cos(θ) (7)

[0062] After performing the processing of step ST30, the information processing device 100 determines whether or not a termination condition has been met (step ST31). In this processing, the information processing device 100 determines whether or not a condition for terminating calculation of the movement distance of the workpiece W1 in the movement direction D1 has been met. For example, the condition for terminating calculation of the movement distance of the workpiece W1 in the movement direction D1 may be that the integrated value of the movement distance of the workpiece W1 in the movement direction D1 has reached a preset value, or that a signal for terminating calculation of the movement distance has been input to the information processing device 100 from an input device (not shown) by an operator operating the input device.

[0063] In the process of step ST31, if the termination condition is not met (NO in step ST31), the information processing device 100 sets the first measured optical information as reference optical information (step ST32) and sets the second measured optical information as the first measured optical information (step ST33). In this process, the information processing device 100 sets the already acquired first measured optical information as reference optical information and the already acquired second measured optical information as the first measured optical information in order to calculate a new movement distance in the movement direction D1 of the workpiece W1 based on the newly acquired optical information. After performing the process of step ST33, the information processing device 100 returns the process to step ST23.

[0064] In the process of step ST31, if the number of times reaches the termination number (YES in step ST31), the information processing device 100 terminates the movement distance calculation process.

[0065] As described above, the information processing device 100 according to the first embodiment includes an optical information acquisition unit 10 that acquires one-dimensional optical information along the measurement direction of the workpiece W1 based on light from the workpiece W1 moving in the movement direction D1; a correlation value calculation unit 20 that calculates a correlation value indicating the correlation between the optical information acquired by the optical information acquisition unit 10 at two different times; an angle estimation unit 30 that estimates the angle between the movement direction D1 and the measurement direction D2 based on the correlation value calculated by the correlation value calculation unit 20; and a movement distance calculation unit 40 that calculates the movement distance Lm1 of the workpiece W1 in the measurement direction D2 based on the optical information acquired by the optical information acquisition unit 10, and calculates the movement distance Lm2 of the workpiece W1 in the movement direction D1 based on the movement distance Lm1 of the workpiece W1 in the measurement direction D2 and the angle estimated by the angle estimation unit 30.

[0066] With this configuration, the information processing device 100 can calculate the movement distance of the workpiece W1 in the movement direction D1 even when the movement direction D1 and the measurement direction D2 are not parallel, thereby improving the accuracy of the calculation result when calculating the movement distance of the workpiece W1 in a non-contact manner. Furthermore, even when the movement direction D1 and the measurement direction D2 are not parallel, the information processing device 100 can calculate the movement distance of the workpiece W1 in the movement direction D1, thereby reducing the effort required for the measurement work compared to starting measurement of the movement distance of the workpiece W1 after installing the optical sensor S1 so that the movement direction D1 and the measurement direction D2 are parallel.

[0067] Furthermore, the information processing device 100 according to the first embodiment is configured to estimate a third angle θ3 based on a first correlation value calculated by the correlation value calculation unit 20 when the angle between the movement direction D1 and the measurement direction D2 is a first angle θ1, a second correlation value calculated by the correlation value calculation unit 20 when the angle between the movement direction D1 and the measurement direction D2 is a second angle θ2 different from the first angle θ1, and a third correlation value calculated by the correlation value calculation unit 20 when the angle between the first direction and the second direction is a third angle θ3, and the movement distance calculation unit 40 calculates the movement distance of the workpiece W1 in the movement direction D1 based on the movement distance of the workpiece W1 in the measurement direction D2 and the third angle θ3. With this configuration, the information processing device 100 can calculate the movement distance of the workpiece W1 in the movement direction D1 by previously understanding the relationship between the angle between the movement direction D1 and the measurement direction D2 and the correlation value.

[0068] In the first embodiment, the information processing device 100 is configured to calculate the movement distance Lm1 of the workpiece W1 in the measurement direction D2 based on the optical information acquired by the optical information acquisition unit 10, and to calculate the movement distance Lm2 of the workpiece W1 in the movement direction D1 based on the movement distance Lm1 of the workpiece W1 in the measurement direction D2 and the angle estimated by the angle estimation unit 30, but is not limited to this. The information processing device only needs to be configured to be able to estimate the angle formed between the movement direction D1 and the measurement direction D2 based on at least the correlation value calculated by the correlation value calculation unit 20, and for example, the information processing device may be configured to calculate only the movement distance Lm1 of the workpiece W1 in the measurement direction D2 as the movement distance of the workpiece W1.

[0069] 12 is a flowchart showing an angle estimation process performed by an information processing device according to a modification of the first embodiment, which is configured to calculate only the movement distance Lm1 of the workpiece W1 in the measurement direction D2 as the movement distance of the workpiece W1. Note that in FIG. 12, processes similar to those performed by the information processing device 100 according to the first embodiment are assigned the same reference numerals as in the first embodiment, and descriptions thereof will be omitted. The angle estimation process shown in FIG. 12 is a process for estimating the angle formed between the movement direction D1 of the workpiece W1 and the measurement direction D2, which is performed in a state in which the regression function calculation process shown in FIG. 7 has been performed, the first regression function and the second regression function have already been calculated, and the angle formed between the movement direction D1 of the workpiece W1 and the measurement direction D2 is unknown.

[0070] As shown in FIG. 12, when an information processing device according to a variation of the first embodiment starts an angle estimation process, it first acquires reference optical information (step ST01). After performing the process of step ST01, the information processing device acquires measured optical information (step ST02). After performing the process of step ST02, the information processing device calculates a correlation value between the reference optical information and the immediately preceding measured optical information (step ST03). After performing the process of step ST03, the information processing device calculates the movement distance of the workpiece W1 in the measurement direction D2 (step ST04). After performing the process of step ST04, the information processing device determines whether the termination count has been reached (step ST05). The set value of the termination count used in this process may be an integer equal to or greater than 2, and may be the same as or different from the set value of the termination count used in the process of step ST05 of the regression function calculation process shown in FIG. 7.

[0071] After performing the processing of step ST5, the information processing device calculates a third regression function (step ST28). After performing the processing of step ST28, the information processing device estimates the angle θ between the movement direction D1 of the workpiece W1 and the measurement direction D2 based on the first regression function, the second regression function, and the third regression function (step ST29). After performing the processing of step ST29, the information processing device according to the modification of embodiment 1 ends the angle estimation processing.

[0072] In this way, even if the information processing device is configured to calculate only the movement distance Lm1 of the workpiece W1 in the measurement direction D2 as the movement distance of the workpiece W1, by estimating the angle between the movement direction D1 and the measurement direction D2, for example, by outputting information indicating the angle estimated by the angle estimation unit 30 to a display device not shown, and displaying the estimated angle on the display device, a worker or the like visually observing the display device can use the estimated angle to move the optical sensor so that the movement direction D1 and the measurement direction D2 become closer to parallel, and when the angle between the movement direction D1 and the measurement direction D2 becomes sufficiently small, calculate the movement distance Lm1 of the workpiece W1 in the measurement direction D2 based on the optical information from the optical sensor, thereby improving the accuracy of the calculation result of the movement distance of the workpiece W1.

[0073] Furthermore, the information processing device does not need to include a movement distance calculation unit that calculates the movement distance of the workpiece W1. Even in such a case, the information processing device can improve the accuracy of the calculation result when the device calculates the movement distance of the workpiece W1 by, for example, outputting the angle estimated by the angle estimation unit 30 to an external device that calculates the movement distance of the workpiece W1.

[0074] Furthermore, in the first embodiment, the information processing device 100 is configured to calculate the movement distance of the workpiece W1 in the movement direction D1, but may also be configured to calculate the movement speed of the workpiece W1 in the movement direction D1 based on the calculation result of the movement distance. For example, the movement speed of the workpiece can be calculated by dividing the movement distance of the workpiece W1 in the movement direction D1 by the image capture interval (exposure interval). Furthermore, the information processing device 100 may be configured to output the calculated movement distance or movement speed to an external device one by one, or may be configured to control the transport of the workpiece W1 based on the calculated movement distance or movement speed.

[0075] Furthermore, in embodiment 1, the information processing device 100 is configured to acquire optical information using the optical sensor S1 based on reflected light from the surface W1a of the workpiece W1, but if the workpiece to be measured is formed from a translucent material, it may be configured to acquire optical information based on transmitted light that passes through the workpiece W1.

[0076] Furthermore, in the first embodiment, the information processing device 100 is configured to calculate a correlation value indicating the correlation between the image data as the reference optical information and the image data as the measurement optical information by a phase-only correlation method, but is not limited to this. The information processing device may be configured to calculate a correlation value indicating the correlation between the optical information acquired at two different times by the optical information acquisition unit, and may be configured to calculate the correlation value using other pattern matching methods such as normalized cross-correlation (NCC), sum of absolute difference (SAD), or sum of squared difference (SSD), or may be configured to use a known method for estimating the correlation value at a pixel unit or less when using these methods.

[0077] In addition, in the present disclosure, any component of the embodiments may be modified or any component of the embodiments may be omitted. [Explanation of symbols]

[0078] 10: Optical information acquisition section 20: Correlation value calculation unit 30:Angle estimation part 40: Travel distance calculation unit 50: Storage section 100: Information processing device D1: Movement direction D2:Measurement direction L1: distance L2: distance LT1:Light source Lm: Travel distance Lm1: Travel distance Lm2: Travel distance OP1: Condenser lens OP2: Imaging lens S1: Optical sensor W1: Work W1a: Surface f4: correlation value t1: 1st time t2: 2nd time t3: 1st time t4: 2nd time x: deviation amount θ: Angle (3rd angle) θ1: Angle (first angle) θ2: angle (second angle)

Claims

1. an optical information acquisition unit that acquires one-dimensional optical information of a workpiece along a second direction based on light from the workpiece moving in a first direction; a correlation value calculation unit that calculates a correlation value indicating a correlation between the optical information acquired by the optical information acquisition unit at two different times; an angle estimation unit that estimates an angle between the first direction and the second direction based on the correlation value calculated by the correlation value calculation unit.

1. An information processing device comprising:

2. The angle estimation unit estimates the third angle based on a first correlation value calculated by the correlation value calculation unit when the angle formed between the first direction and the second direction is a first angle, a second correlation value calculated by the correlation value calculation unit when the angle formed between the first direction and the second direction is a second angle different from the first angle, and a third correlation value calculated by the correlation value calculation unit when the angle formed between the first direction and the second direction is a third angle.

2. The information processing apparatus according to claim 1, wherein:

3. The angle estimation unit calculates, by regression analysis, a first function indicating the relationship between the first correlation value and the movement distance of the workpiece in the second direction, a second function indicating the relationship between the second correlation value and the movement distance of the workpiece in the second direction, and a third function indicating the relationship between the third correlation value and the movement distance of the workpiece in the second direction, and estimates the third angle based on the first angle, the second angle, the first function, the second function, and the third function.

3. The information processing apparatus according to claim 2.

4. The angle estimation unit calculates the first function, the second function, and the third function by linear regression analysis.

4. The information processing apparatus according to claim 3.

5. a movement distance calculation unit that calculates a movement distance of the workpiece in the second direction based on the optical information acquired by the optical information acquisition unit, and calculates a movement distance of the workpiece in the first direction based on the movement distance of the workpiece in the second direction and the angle estimated by the angle estimation unit.

5. The information processing apparatus according to claim 1, wherein the information processing apparatus is a computer.

6. The movement distance calculation unit calculates the movement distance of the workpiece in the first direction based on the movement distance of the workpiece in the second direction and the third angle.

6. The information processing apparatus according to claim 5,

7. An information processing method performed by an apparatus including an optical information acquisition unit, a correlation value calculation unit, an angle estimation unit, and a movement distance calculation unit, The optical information acquisition unit acquires one-dimensional optical information of the workpiece along a second direction based on light from the workpiece moving in a first direction; a step in which the correlation value calculation unit calculates a correlation value indicating a correlation between optical information acquired at two different times by the optical information acquisition unit; and a step in which the angle estimation unit estimates an angle between the first direction and the second direction based on the correlation value calculated by the correlation value calculation unit.

1. An information processing method comprising:

Images