JP5723096B2 - Distance image processing system - Google Patents

Description

  The present invention relates to a distance image processing system, and more particularly to a distance image processing system that can obtain an absolute distance value using a distance image sensor using a two-dimensional scanner such as a planar actuator.

  Conventionally, as an actuator having a structure in which a plate-like movable part is pivotally supported on a frame-like fixed part, for example, using a semiconductor manufacturing technique, a silicon substrate is anisotropically etched to form a frame-like fixed part. A flat movable part and a torsion bar that pivotally supports the movable part are integrally formed on the fixed part, a drive coil is provided on the movable part, and a static magnetic field is applied to the drive coil of the movable part, for example, a static magnet such as a permanent magnet. There is an electromagnetically driven planar actuator that provides a magnetic field generating means and rotates a movable part using Lorentz force generated by the interaction between a magnetic field generated in a drive coil by energization and a static magnetic field generated by a static magnetic field generating means . A technique is disclosed in which an image is captured by irradiating light to the actuator while driving such an actuator, scanning the light in a two-dimensional region, and receiving the reflected light. (For example, refer to Patent Document 1).

  In recent years, as a device that forms such an image, the actuator is irradiated with light to scan the detection target region, and the reflected light is received to obtain the distance value of the two-dimensional region to be detected. A distance image sensor has been developed, and various image processes are performed by generating a frame image based on a distance value obtained by the distance image sensor.

Japanese Patent No. 4214364

  However, in the prior art, in order to accurately measure the distance by the distance image sensor, an absolute distance value is required. There is a problem that timing deviation occurs and it is extremely difficult to always measure the absolute distance value.

  In the distance image sensor, a person or an object is extracted based on a difference image from a background image generated based on a distance value obtained by the distance image sensor. Since the background image is set in advance, if the background changes due to changes in the installation position of the distance image sensor, etc., the background image must be set each time, which is troublesome. doing.

  The present invention has been made in view of the above points, and even when the installation position of the distance image sensor is changed, a background image can be easily generated, and even when environmental temperature and secular change occur, It is an object of the present invention to provide a distance image processing system capable of always performing accurate distance measurement.

In order to achieve the above object, the distance image processing system according to the first aspect of the present invention generates a background image based on a distance value of each pixel input from a distance image sensor targeting a scanning region. And an image data processing device including an image processing circuit that generates a distance image from the difference between the distance value of the background image and the newly acquired distance value,
The image processing circuit, by the distance image sensor to generate the refresh timing comes repeatedly advance distance values of the acquired pixels are is stored distance value having the maximum of each pixel when it becomes the generating refresh timing By generating a background image based on the maximum distance value, it is configured to generate a distance image using the background image generated at the previous generation refresh timing until the next generation refresh timing comes. Features .

According to a second aspect of the present invention, in the first aspect , the distance image sensor includes a planar actuator, and includes a two-dimensional scanner that scans light in a two-dimensional area corresponding to the scanning area. To do.

According to a third aspect of the present invention, in the first or second aspect , the image processing circuit is configured to reset a maximum distance value stored at each generation refresh timing.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the image processing circuit measures in advance a distance value of a reference pixel acquired by the distance image sensor. And calculating the difference between the measured distance from the installed position of the distance image sensor to the reference point corresponding to the reference pixel and correcting the distance values of all the pixels by the distance image sensor based on the difference. It is comprised by these.

According to a fifth aspect of the invention, in any one of the first to fourth aspects, the image processing circuit approaches the distance image sensor side with respect to a maximum distance value measured by the distance image sensor. A distance measurement fluctuation range that is a range of a distance is set, and when the distance value measured by the distance image sensor is in the distance measurement fluctuation range, the distance value is not used. To do.

  According to the first aspect of the present invention, the distance value that maximizes the distance value of each pixel acquired by the distance image sensor is stored by the image processing circuit, and the background is based on the maximum distance value of each pixel. Since the image is generated, the background image can be easily generated even when the installation position of the distance image sensor is changed.

According to the second aspect of the present invention, the distance image sensor includes a planar actuator and includes a two-dimensional scanner that scans light in a two-dimensional region, so that light can be scanned quickly and reliably. it can.

According to the invention of claim 3 , since the maximum distance value stored for each generation refresh timing is reset by the image processing circuit, the distance value for generating the background image for each generation refresh timing. Can be newly acquired.

According to the fourth aspect of the present invention, the distance value of the reference pixel acquired by the distance image sensor by the image processing circuit and the reference pixel from the installation position of the distance image sensor measured in advance. The difference between the measurement distance to the corresponding reference point is calculated, and the distance value of all pixels by the distance image sensor is corrected based on this difference. Even when the measured distance value fluctuates, it can be reliably corrected to an absolute distance value, and accurate distance measurement can always be performed.

According to the invention of claim 5 , the image processing circuit sets a distance measurement fluctuation range that is a range of distance approaching the distance image sensor side with respect to the maximum distance value measured by the distance image sensor, When the distance value measured by the distance image sensor is within the distance fluctuation range, this distance value is not used, so the maximum value can be obtained without using an abnormal distance value measured larger than the original distance. Can be obtained, and the accuracy of the background image can be improved.

1 is a schematic configuration diagram showing a first embodiment of a distance image processing system according to the present invention. It is the schematic which shows embodiment of the two-dimensional scanner used for the distance image processing system which concerns on this invention. It is explanatory drawing which shows the example of acquisition of the distance value by the distance image processing system which concerns on this invention. It is explanatory drawing which shows the example of correction | amendment using the reference point by the distance image processing system which concerns on this invention. It is explanatory drawing which shows the example of correction | amendment using the some reference point by the distance image processing system which concerns on this invention. It is a flowchart which shows the production | generation operation | movement of the background image by the distance image processing system which concerns on this invention. It is a flowchart which shows the correction | amendment operation | movement of the distance value by the distance image processing system which concerns on this invention. It is explanatory drawing which shows the example of acquisition of the distance value using the ranging fluctuation range by the distance image processing system which concerns on this invention.

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

  FIG. 1 shows a first embodiment of a distance image processing system according to the present invention. The distance image processing system performs image processing based on a distance image sensor 1 and a distance value sent from the distance image sensor 1. An image data processing device 2 is provided.

  The distance image sensor 1 includes a two-dimensional scanner 10. In the present embodiment, a planar actuator is used as the two-dimensional scanner 10.

  As shown in FIG. 2, the two-dimensional scanner 10 of the present embodiment includes a frame-shaped fixing unit 11 installed on a device substrate (not shown). A frame-shaped second movable portion 13 is swingably supported inside the fixed portion 11 via a second torsion bar 12, and the first torsion bar is located inside the second movable portion 13. The first movable portion 15 is supported via the 14 so as to be swingable. That is, the first movable part 15 and the second movable part 13 are swingable in directions orthogonal to each other via the second torsion bar 12, and the first movable part 15 and the second movable part 13 are , It is configured to be driven at different drive frequencies. The fixed portion 11, the second movable portion 13, the first movable portion 15, the first torsion bar 14, and the second torsion bar 12 are integrally formed.

  A drive coil (not shown) for driving the first movable part 15 is provided on the first movable part 15, and a drive coil (not shown) for driving the second movable part 13 is provided on the second movable part 13. Two pairs of static magnetic field generating members (not shown) are disposed around the fixed portion 11 and are arranged with opposite magnetic poles facing each other with the first movable portion 15 interposed therebetween. The static magnetic field generating member may be a permanent magnet or an electromagnet.

  As shown in FIG. 1, the distance image sensor 1 includes a control unit 20, and the control unit 20 is provided with a laser controller 21 for controlling the laser beam and the scanner. The control unit 20 is provided with a scanner driver 22 to which an inner shaft driving signal and an outer shaft driving signal from the laser controller 21 are input. The scanner driver 22 is provided for the two-dimensional scanner 10 with respect to the laser controller 21. The inner shaft drive signal for driving the first movable portion 15 and the outer shaft drive pulse for driving the second movable portion 13 based on the inner shaft drive signal and the outer shaft drive signal output from Is configured to output. A scanner synchronization signal for detecting the driving positions of the first movable unit 15 and the second movable unit 13 is sent via a filter 23 from a detection device (not shown) of the two-dimensional scanner 10 to the laser controller 21 of the control unit 20. It is configured as follows.

  Further, the distance image sensor 1 includes a laser projector 24, and the laser projector 24 is provided with a laser element 25 for emitting laser light. The laser projector 24 is provided with a laser driver 26 that outputs a projection drive pulse to the laser element 25 based on a laser emission timing signal sent from the laser controller 21. In the laser projector 24, a projecting optical device 28 configured by, for example, a mirror or a lens for projecting the laser beam emitted from the laser element 25 to the two-dimensional scanner 10 via the beam splitter 27. Is provided. Furthermore, a light emission monitor 29 for monitoring the light projection timing of the laser light is connected to the light projecting optical device 28. The light emission monitor 29 includes a light receiving element (not shown). The light receiving element receives the laser light projected from the light projecting optical device 28 to monitor the light projecting timing by the light projecting optical device 28. The projection timing signal is output to a time measuring circuit 38 to be described later.

  The distance image sensor 1 further includes a laser light receiving unit 30, and the laser light receiving unit 30 is provided with a light receiving element 31 for receiving laser light. The laser light receiving unit 30 is configured by, for example, a mirror or a lens for causing the light receiving element 31 to receive the laser light projected from the laser element 25 via the light projecting optical device 28 and reflected by the two-dimensional scanner 10. A light receiving optical device 32 is provided. The laser light receiving unit 30 is provided with a preamplifier 33 that amplifies a light reception signal from the light receiving element 31.

  The distance image sensor 1 includes a distance measuring unit 34. The distance measuring unit 34 includes a resonance circuit 35 and a rising circuit 36 for detecting a light reception signal transmitted from the preamplifier 33 of the laser light receiving unit 30. Each is provided. The resonance circuit 35 is mainly used when the distance to be measured is relatively long, and the rising circuit 36 is mainly used when the distance to be measured is relatively short. The distance measurement unit 34 is provided with stop timing generation circuits 37 and 37 that generate timings received by the light receiving element 31 based on light reception signals sent via the resonance circuit 35 and the rising circuit 36. The distance measuring unit 34 measures time from the light reception timing generated by the stop timing generation circuit 37 and the light projection timing signal sent from the light emission monitor 29 to measure the time from the light projection timing to the light reception timing. Circuits 38, 38 are provided.

  Further, the control unit 20 is provided with a distance value calculation circuit 39, and time data from the time measurement circuit 38 is sent to the distance value calculation circuit 39 via the A / D converters 40 and 40. ing. The distance value calculating circuit 39 is configured to be able to acquire a distance value based on the time data from the time measuring circuit 38. The acquired distance value is an image to be described later via the external interface 41. It is configured to be output to the data processing device 2. That is, by operating the first movable part 15 and the second movable part 13 of the two-dimensional scanner 10 and projecting laser light from the laser projecting part 24 to the two-dimensional scanner 10, laser light is generated in a two-dimensional region. The laser beam projected from the two-dimensional scanner 10 and reflected by the object is reflected by the two-dimensional scanner 10 and received by the laser light receiving unit 30, so that each pixel in the range scanned by the two-dimensional scanner 10 is scanned. The distance value at can be acquired. The laser light receiving unit 30 is provided with an A / D converter 42 that A / D converts the light reception signal output from the preamplifier 33 and sends it to the distance value calculation circuit 39 as the amount of received light.

  Further, the control unit 20 is provided with a main power supply 43 for supplying power to the control unit 20 and the distance measurement measurement unit 34. Further, the control unit 20 receives the power supply from the main power supply 43 and receives the laser driver 26, preamplifier 33 and an HV power supply 44 for supplying power to the scanner driver 22 is provided.

  Further, the image data processing device 2 is provided with an image processing circuit 46 that generates a two-dimensional frame image based on a distance value acquired at each pixel input from the distance image sensor 1 via the input interface 45. It has been. The image processing circuit 46 is configured to store, for example, the distance value in each pixel for each frame by each scanning by the two-dimensional scanner 10, and the largest distance value in each pixel, that is, the farthest distance. An image generated by a value is stored as a background image, and a distance image is generated by obtaining a difference between the distance value of the background image and a newly acquired distance value with reference to the background image. Has been.

  More specifically, as shown in FIG. 3, in this embodiment, the image processing circuit 46 is based on the distance value acquired in each pixel input from the distance image sensor 1 via the input interface 45. The distance value at which each distance value is the maximum value is stored in the distance value memory 47, and this is repeated until the generation refresh timing comes. Then, when the generation refresh timing is reached, the background image is generated based on the maximum distance value of each pixel stored in the distance value memory 47. For example, the generation refresh timing can be set as appropriate according to how many frames the generation refresh timing is provided.

  Then, after generating the background image, the image processing circuit 46, as shown in FIG. 4, the distance value of the reference pixel acquired by the distance image sensor 1 and the distance image sensor 1 measured in advance. This difference is calculated by comparing the measured distance from the installation position to the reference point. Since the difference between the distance values is an error from the actual distance, the distance image sensor 1 is configured to correct the distance values of all the pixels based on the error. The background image is also corrected based on the corrected distance value. Thereby, the distance value as the background is determined, and the background image is generated based on the corrected distance value.

  The image processing circuit 46 generates a background image based on the corrected distance value, resets the distance value stored in the distance value memory 47, performs the same operation as described above, and performs the next generation refresh timing. The same operation is repeated, and the distance value at which each distance value becomes the maximum value is stored in the distance value memory 47. The image information by the image processing circuit 46 is configured to be output to an external device (not shown) via the output interface 48.

  In the embodiment, the correction amount is calculated using one pixel as a reference point. However, for example, when the distance value for one pixel becomes abnormal, the correction amount is calculated based on the abnormal distance value. If calculated, there is a risk that accurate correction cannot be performed. Therefore, for example, as shown in FIG. 5, based on the distance values for a plurality of pixels existing around the reference point, the average value of these distance values may be adopted as the distance value for the reference point. Good. In this case, when a distance value greatly deviated from the distance values in the plurality of pixels is measured, the deviated distance value is not used for calculating the average value, and is based on other distance values. The correction amount may be calculated. As a result, the correction amount can be accurately calculated.

  Next, the operation of this embodiment will be described.

  First, the laser controller 21 causes the scanner driver 22 to output the inner axis driving signal and the outer axis driving signal, and the scanner driver 22 causes the two-dimensional scanner 10 to output the inner axis driving pulse and the outer axis driving pulse. The drive coil of the three-dimensional scanner 10 is energized, thereby causing the first movable portion 15 and the second movable portion 13 to swing.

  In this state, first, the laser emission timing signal is output from the laser controller 21 to the laser projector 24. When a laser emission timing signal is input to the laser projector 24, the laser driver 26 outputs a projection drive pulse to the laser element 25, so that the laser beam is two-dimensionally transmitted from the laser element 25 via the projection optical device 28. The light is projected to the scanner 10.

  Then, the laser light is scanned in the two-dimensional region by the two-dimensional scanner 10, and the laser light projected from the two-dimensional scanner 10 and reflected by the object is reflected by the two-dimensional scanner 10 and passes through the light receiving optical device 32. The laser light receiving unit 30 receives the light. This light reception signal is output to the time measurement circuit 38 via the resonance circuit 35 or the rising circuit 36 and the stop timing generation circuit 37.

  The time measurement circuit 38 measures the time from the light projection timing to the light reception timing from the light reception timing generated by the stop timing generation circuit 37 and the light projection timing sent from the light emission monitor 29, and the distance value calculation circuit. 39 is output. Then, the distance value calculation circuit 39 calculates the distance value at each pixel in the range scanned by the two-dimensional scanner 10 based on the time data from the time measurement circuit 38, and this distance value is sent to the image data processing device 2. It is done.

  Next, the operation of generating a background image by the image data processing device 2 will be described with reference to the flowchart shown in FIG.

  When the distance value is acquired by the image data processing device 2 by the above-described operation (ST1), the image processing circuit 46 determines whether the distance value in the previous frame is large (ST2), and in the previous frame. If the distance value acquired this time is larger than the distance value, the distance value acquired this time is stored in the distance value memory 47 instead of the distance value in the previous frame (ST3). If the distance value acquired this time is smaller than the distance value in the previous frame, the distance value is not replaced. This operation is repeated until the generation refresh timing. When the generation refresh timing is reached (ST4), a background image is generated based on the distance value stored in the distance value memory 47. Thereafter, the distance value stored in the distance value memory 47 is reset (ST5), and the distance value of the next frame is measured (ST6).

  Next, the distance value correcting operation by the image data processing apparatus will be described with reference to the flowchart shown in FIG.

  Until the first refresh timing is reached (ST10: YES), the distance value of the pixel that becomes the reference point of the background image is acquired (ST11), the distance value of the pixel that becomes the reference point, and the installation position of the distance image sensor 1 The correction amount is determined by calculating the difference from the measurement distance from the reference point to the reference point (ST12). Then, the distance values of all the pixels are corrected based on the correction amount (ST13). Thereafter, the next frame is corrected (ST14).

  When the next generation refresh timing is reached (ST15: YES), the distance value of the pixel serving as the reference point of the background image is acquired (ST11), and the distance value of the pixel serving as the reference point is obtained in the same manner as described above. The correction amount is determined by calculating the difference with the measurement distance from the installation position of the distance image sensor 1 to the reference point (ST12), and the distance values of all the pixels are corrected based on this correction amount (ST13).

  As described above, in the present embodiment, the maximum distance value acquired by the distance image sensor 1 is stored, and the background image is generated based on this distance value. Even when the installation position is changed, a background image can be easily generated. Further, based on the difference between the distance value of the reference pixel acquired by the remote image sensor and the measured distance from the installation position of the distance image sensor 1 to the reference point measured in advance, the distance image sensor 1 Since the distance values of all the pixels are corrected, even if the distance value measured by the distance image sensor 1 fluctuates due to the environmental temperature or secular change, it can be surely corrected to the absolute distance value. Accurate distance measurement can be performed.

  As shown in FIG. 8, a distance measurement fluctuation range, which is a range of distances approaching the distance image sensor 1 with respect to the maximum distance value measured by the distance image sensor 1, is set. This distance value may not be used when the distance value measured by is in the distance measurement fluctuation range.

  For example, when storing a maximum distance value, if a distance value larger than the original distance is once measured due to some abnormality, if a background image is generated based on this distance value, the background image There is a possibility that the accuracy of the is impaired. However, in this way, if the distance value in the ranging fluctuation range is not used, the maximum distance value can be obtained without using the abnormal distance value measured larger than the original distance, The accuracy of the background image can be increased.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible based on the meaning of this invention.

DESCRIPTION OF SYMBOLS 1 Distance image sensor 2 Image data processor 3 Output device 10 Two-dimensional scanner 11 Fixed part 13 2nd movable part 15 1st movable part 20 Control part 21 Laser controller 22 Scanner driver 24 Laser projector 25 Laser element 26 Laser driver 28 Light projecting optical device 29 Light emission monitor 30 Laser light receiving unit 31 Light receiving element 32 Light receiving optical device 34 Distance measuring unit 37 Stop timing generating circuit 38 Time measuring circuit 39 Distance value calculating circuit 46 Image processing circuit 47 Memory for distance value

Claims (5)

A background image is generated based on the distance value of each pixel input from the distance image sensor for the scanning area, and a distance image is generated from the difference between the distance value of the background image and the newly acquired distance value. An image data processing device including an image processing circuit for performing,
The image processing circuit, by the distance image sensor to generate the refresh timing comes repeatedly advance distance values of the acquired pixels are is stored distance value having the maximum of each pixel when it becomes the generating refresh timing by generating the background image based on the maximum distance value, until arrival of the next generation refresh timing is configured to generate a distance image by using the background image generated by the generating refresh timing before the distance Image processing system. The distance image processing system according to claim 1 , wherein the distance image sensor includes a planar actuator, and includes a two-dimensional scanner that scans light in a two-dimensional area corresponding to the scanning area. The image processing circuit, the distance image processing system according to claim 1 or claim 2, characterized in that it is configured to reset the maximum and becomes the distance values stored for each generated refresh timing. The image processing circuit includes a distance value of a reference pixel acquired by the distance image sensor and a measurement distance from a previously installed position of the distance image sensor to a reference point corresponding to the reference pixel. by calculating the difference between any one of claims 1 to 3, characterized in that it is configured to correct the distance value of all the pixels by the distance image sensor on the basis of this difference The distance image processing system described in 1. The image processing circuit sets a distance measurement fluctuation range which is a range of distance approaching the distance image sensor side with respect to a maximum distance value measured by the distance image sensor, and is measured by the distance image sensor. The distance image processing system according to any one of claims 1 to 4 , wherein the distance value is configured not to be used when the distance value is within the distance measurement fluctuation range.

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