JP5045447B2 - POSITION INFORMATION ACQUISITION DEVICE, POSITION ESTIMATION DEVICE, AND MOBILE BODY - Google Patents

Description

  The present invention relates to a position information acquisition device, a position estimation device, and a moving object.

  In recent years, robots that are expected to be used in various applications have attracted attention. For example, a partner robot that provides an amusement such as playing a musical instrument, a partner robot that provides care to a care recipient, and a robot that assists in production of a production line are attracting attention.

  When realizing a high-performance robot, it is required that the robot move in a space or realize a desired operation according to a dialogue with a human. When it is required to move in a space, it is required to grasp the position in a certain space with high accuracy. In this case, a technique for detecting the position of the robot in the space using a so-called optical tag may be used.

  Patent Document 1 discloses a technique related to an optical tag. In Patent Document 1, a high-speed tag reader that detects detailed information and a low-speed tag reader that detects category information are provided. Thus, transmission of various attribute information including category information and detailed information is realized.

Patent Document 2 discloses an optical moving image detection apparatus. Further, Patent Document 3 discloses a visual sensor.
JP 2007-184785 A Japanese Patent Laid-Open No. 5-2198 JP 2000-20880 A

  By the way, in order to acquire position information used when estimating the position of a robot in a certain space, an optical signal from an external light source is detected by an image sensor incorporated in the robot. There is a problem like this.

  There is an area where no optical signal is input on the imaging surface of the imaging element, and an image captured in this area is wasted. Driving the image sensor at a higher speed is hindered by the time required to read out this useless image.

  Further, when the optical signal is pulsed, the image acquired by the image sensor includes an image in which the optical signal is not captured, and this image is wasted. The burden of image processing in the image processing unit to which the output of the image sensor is connected is increased by the number of useless images output from the image sensor.

  Thus, it is strongly desired to acquire the position information used when estimating the position of the robot without waste.

  The present invention has been made to solve such a problem, and an object of the present invention is to acquire position information used when estimating the position of a moving body (for example, a robot) more efficiently than conventionally.

  The position information acquisition apparatus according to the present invention is a position information acquisition apparatus that acquires position information based on detection of an optical signal coming from the outside, and an optical branching unit that branches the optical signal in first and second directions. And a light detection element that receives the optical signal guided in the first direction through the light branching means, an imaging surface on which a plurality of pixels are arranged, and the second through the light branching means. An image sensor that receives the optical signal guided in a direction at one or more of the pixels, and causes the image sensor to read signals from some of the pixels based on an output of the light detection element, or A control unit that controls a timing at which the imaging device captures an image based on an output of the light detection device.

  The control unit causes the image sensor to read signals from some of the plurality of pixels based on the output of the light detection element. As a result, it is possible to limit the area where signals are actually read out to a range narrower than the imaging surface. The control unit controls the timing at which the imaging element captures an image based on the output of the light detection element. Thereby, an unnecessary image captured by the image sensor can be eliminated. In this way, unnecessary images can be eliminated.

  The light detection element may be a position detection element that detects an incident position of the optical signal in a light receiving region corresponding to the imaging surface.

  The control unit sets a reading range in a part of the imaging surface of the imaging element based on a signal indicating an incident position of the optical signal in the light receiving region output from the light detection element, and It is preferable to read signals from the pixels within the reading range.

  The position information acquisition apparatus according to claim 1, wherein the optical signal is output from a light source provided outside in advance, and at least a signal for identifying the light sources is superimposed thereon.

  It is preferable to further include a signal decoding unit that decodes a signal superimposed on the optical signal based on the output of the light detection element and / or the imaging element.

  The light detection element may be a light receiving element that outputs a current having a value corresponding to an incident light intensity.

  The control unit includes the imaging element based on a signal indicating input or non-input of the optical signal output from the light receiving element, in all or part of the plurality of pixels included in the imaging surface of the imaging element. It is good to let them image.

  The optical signal may be output from a light source provided outside in advance, and at least a signal for identifying the light sources may be superimposed.

  It is good to further have a signal decoding part which decodes a signal superimposed on the optical signal based on an output of the light receiving element.

  A threshold value determination unit that determines a threshold value based on an output from the light detection element, and an image process that performs binarization processing on an image output from the imaging element based on the threshold value determined by the threshold value determination unit And a section.

  The light branching unit may be a beam splitter that guides a part of the optical signal to each of the light detection element and the image pickup element.

  The position estimation apparatus according to the present invention is a position estimation apparatus that estimates a position in space based on detection of an optical signal coming from the outside, and an optical branching unit that branches the optical signal in first and second directions. And a light detection element that receives the optical signal guided in the first direction through the light branching means, an imaging surface on which a plurality of pixels are arranged, and the second through the light branching means. An image sensor that receives the optical signal guided in a direction at one or more of the pixels, and causes the image sensor to read signals from some of the pixels based on an output of the light detection element, or A control unit that controls the timing at which the imaging device captures an image based on the output of the light detection device, and an incident position of the optical signal within the imaging surface based on an image output from the imaging device, and the detection Based on results And a position estimation unit that estimates a place in the space.

  The position estimation unit may specify an incident position of the optical signal in the imaging surface based on obtaining a difference between an image in which the optical signal is copied and an image in which the optical signal is not copied. .

  The moving body according to the present invention includes the above-described position information acquisition apparatus or position estimation apparatus.

  ADVANTAGE OF THE INVENTION According to this invention, the positional information used when estimating the presence position of a moving body can be acquired more wastefully than before.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each embodiment is simplified for convenience of explanation. Since the drawings are simple, the technical scope of the present invention should not be interpreted narrowly based on the drawings. The drawings are only for explaining the technical matters and do not reflect the exact sizes of the elements shown in the drawings. The same elements are denoted by the same reference numerals, and redundant description is omitted.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram illustrating a configuration of a movement control system. FIG. 2 is a block diagram illustrating a schematic configuration of the position estimation apparatus. FIG. 3 is an explanatory diagram illustrating a schematic configuration of an imaging unit incorporated in the robot. FIG. 4 is a schematic diagram showing a schematic top configuration of the PSD. FIG. 5 is a schematic diagram showing a schematic top configuration of the CMOS imager 6. FIG. 6 is a flowchart for explaining the operation of the position estimation apparatus. FIG. 7 is an explanatory diagram for explaining a method of specifying an incident position of an optical signal.

  As shown in FIG. 1, the movement control system 300 includes a robot (moving body) 100 and a light emitting device (light emitting source) 200.

  The light emitting device 200 is fixed in advance at a predetermined location in the space (for example, an indoor ceiling). The light emitting device 200 outputs a pulsed optical signal (hereinafter also referred to as a pulsed optical signal or simply an optical signal) to space.

  The light emitting device 200 includes a light emitting unit (light source) 201 and a driving unit 202. The light emitting unit 201 is a semiconductor light emitting element such as an LD (Laser Diode) or an LED (Light Emitting Diode). The light emitting unit 201 emits light in the infrared band. The drive unit 202 pulse-drives the light emitting unit 201 in accordance with a program previously written in a storage unit such as a ROM. The configuration of the drive unit 202 is arbitrary. In addition, a plurality of light emitting devices 200 may be provided in the space to make the movement range of the robot 100 wider or highly accurate.

  The robot 100 receives an optical signal output from the light emitting device 200 and detects a place where the robot is present based on the optical signal. Note that the robot 100 is a robot capable of autonomous movement and dialogue with a human, and includes a head 90, a torso 91, arms 92, and wheels 93 as shown in FIG.

  Various parts are incorporated in the housing of the robot 100. For example, a controller that controls the operation of the robot 100, a drive mechanism that is mechanically movable based on a command from the controller, a sensor that acquires information to be processed by the controller, a processing circuit that processes input from the sensor, a display device, and the like And a secondary battery (power source) for supplying power to the electronic device are mounted in the housing of the robot 100.

  The controller is composed of a normal computer and has a CPU, a motherboard, and an external storage device (such as a hard disk). The drive mechanism is configured by a motor, an actuator, a mechanical link, and the like. The sensors are various sensors such as an image sensor, a microphone, and a thermal element. The processing circuit is a circuit component such as an A / D conversion circuit and a signal processing circuit. The notification mechanism is means for transmitting some information to a human by video, sound, and light, such as a liquid crystal display device, a speaker, and an LED (Light Emitting Diode).

  The controller controls the drive mechanism or the notification mechanism based on a signal input from the sensor. In this way, the robot 100 moves in the space as necessary, or notifies the human being of some information as necessary.

  The robot 100 incorporates the position estimation device 60 shown in FIG. Based on the optical signal output from the light emitting device 200, the position estimation device 60 estimates the location where the robot 100 incorporating the position estimation device 60 is present. By incorporating the position estimation device 60 into the robot 100, the robot can be moved autonomously in space. Thereby, the utilization range of the robot 100 can be expanded.

  As shown in FIG. 2, the position estimation device 60 includes an optical system 1, a beam splitter (light splitting means) 2, a position detection sensor (light detection element) 3, a signal processing circuit 4, an arithmetic processing unit 5, and a CMOS imager ( An imaging device) 6. The arithmetic processing unit 5 includes a sensor control unit (control unit) 5a, an image processing unit 5b, a signal decoding unit 5c, and a position estimation unit 5d.

  The position estimation apparatus 60 incorporates a position information acquisition apparatus that acquires position information used when estimating the position. The position information acquisition apparatus includes a beam splitter 2, a position detection sensor 3, a signal processing circuit 4, a sensor control unit 5a, and a CMOS imager 6.

  First, input / output relationships of elements included in the position estimation device 60 will be described.

  An optical signal (OPS (Optical Signal)) output from the light emitting device 200 is input to the optical system 1. The optical signal output from the optical system 1 is input to the beam splitter 2. The light branched in the first direction by the beam splitter 2 is input to the position detection sensor 3. The signal S1 output from the position detection sensor 3 is input to the signal processing circuit 4. A signal S2 output from the signal processing circuit 4 is input to the arithmetic processing unit 5. The light branched in the second direction by the beam splitter 2 is input to the CMOS imager 6. The signal S3 output from the arithmetic processing unit 5 is input to the CMOS imager 6. The signal S4 output from the CMOS imager 6 is input to the arithmetic processing unit 5.

  Hereinafter, the optical system 1, the beam splitter 2, the position detection sensor 3, and the CMOS imager 6 will be described with reference to FIGS. 3 to 5 together. In addition, the position estimation apparatus 60 has the imaging unit 50 shown in FIG.

  The optical system 1 includes at least one optical element (for example, a lens). As shown in FIG. 3, the optical system 1 includes an entrance window 10 and an objective lens 11. External light including an optical signal that arrives from the light emitting device 200 through space is input to the incident window 10. The objective lens 11 focuses the extraneous light that has passed through the incident window 10 on the light receiving region of the position detection sensor 3 and the imaging surface of the CMOS imager 6.

  The beam splitter 2 is an optical component that makes a half of input light go straight and reflects the other half of the input light. As shown in FIG. 3, the beam splitter 2 causes a half of the optical signal to go straight and reflects a half of the optical signal. The optical signal that has passed through the beam splitter 2 is input to the CMOS imager 6. The optical signal reflected by the beam splitter 2 is input to the position detection sensor 3.

  The position detection sensor 3 is a general position detection element made of a semiconductor material. In the position detection sensor 3, a second conductive type resistance layer is formed on the main surface of the first conductive type semiconductor substrate. A plurality of divided signal extraction electrodes are formed around the resistance layer. The resistance layer is connected to the ground potential, and the signal extraction electrode is connected to the semiconductor substrate.

  As illustrated in FIG. 4, the position detection sensor 3 includes a light receiving region 20 and a plurality of signal extraction electrodes 21 a to 21 d. In the light receiving region 20, the above-described resistance layer is formed. The signal extraction electrodes 21 a to 21 d are arranged around the light receiving region 20. When an optical signal enters the range R1 schematically shown in FIG. 4, a photocurrent having a value corresponding to the incident position of the optical signal in the light receiving region 20 is output from each of the signal extraction electrodes 21a to 21d.

  From the signal extraction electrode 21a, a photocurrent having a value corresponding to the distance between the signal extraction electrode 21a and the range R1 is output as a signal S1a. From the signal extraction electrode 21b, a photocurrent having a value corresponding to the distance between the signal extraction electrode 21b and the range R1 is output as a signal S1b. By detecting the ratio between the signal S1a and the signal S1b, the position along the y-axis (y coordinate) of the optical signal incident on the light receiving region 20 can be detected. This arithmetic processing is executed by a signal processing circuit 4 described later. The y axis is an axis perpendicular to the propagation direction of the optical signal arriving at the position detection sensor 3 from the outside.

  From the signal extraction electrode 21c, a photocurrent having a value corresponding to the distance between the signal extraction electrode 21c and the range R1 is output as a signal S1c. From the signal extraction electrode 21d, a photocurrent having a value corresponding to the distance between the signal extraction electrode 21d and the range R1 is output as a signal S1d. By detecting the ratio between the signal S1c and the signal S1d, the position (x coordinate) along the x-axis of the optical signal incident on the light receiving region 20 can be detected. This arithmetic processing is executed by a signal processing circuit 4 described later. The x axis is an axis that is orthogonal to the propagation direction of the optical signal arriving at the position detection sensor 3 from the outside and orthogonal to the y axis.

  The signal processing circuit 4 shown in FIG. 2 outputs signals S2 (S2a, S2b) generated based on the signals S1 (S1a to S1d) output from the position detection sensor 3. More specifically, the signal processing circuit 4 calculates the ratio between the signal S1a and the signal S1b and the ratio between the signal S2a and the signal S2b.

  Here, the signal processing circuit 4 includes a transimpedance circuit and a logic circuit. Photocurrents as signals S1a to S1d input from the position detection sensor 3 are converted into voltages via a transimpedance circuit. The signals that have been voltage-converted by each truss impedance circuit are subjected to arithmetic processing by a logic circuit, and are output as a signal S2a indicating the x coordinate and a signal S2b indicating the y coordinate. Note that the specific configuration of the logic circuit is arbitrary.

  A CMOS (Complementary Metal Oxide Semiconductor) sensor 6 shown in FIG. 2 is a general solid-state imaging device. More preferably, the optical path length between the beam splitter 2 and the CMOS imager 6 is longer than the optical path length between the beam splitter 2 and the position detection sensor 3.

  As shown in FIG. 5, the CMOS imager 6 includes an imaging region 30 as an imaging surface, a row selection circuit 31, a column selection circuit 32, switches SW1 to SW6, and a data transfer line 33. In FIG. 5, for convenience of explanation, the reset line, the power supply line, the switch in the pixel, the diode structure in the pixel, the amplifier in the pixel, and the like are not shown.

  In the imaging region 30, a plurality of pixels 11 to 66 are formed in a matrix (two-dimensional). Note that the pixel 11 is a pixel specified by the address of the first column in the first row. The pixel 66 is a pixel specified by the address of the sixth row and the sixth column. The same applies to other pixels.

  The imaging region 30 and the above-described light receiving region 20 are similar. Thereby, the coordinate position on the light receiving area 20 and the coordinate position on the imaging area 30 can be easily associated with each other. Note that the area of the imaging region 30 does not necessarily match the area of the light receiving region 20.

  The row selection circuit 31 selects a specific row according to a selection instruction from the sensor control unit 5a. The column selection circuit 32 selects a specific column in accordance with a selection instruction from the sensor control unit 5a. The column selection circuit 32 selects a column based on controlling the operation state of the switches SW1 to SW6. The voltage signal included in the row selected by the row selection circuit 31 and held in the pixel included in the column selected by the column selection circuit 32 is output to the outside via the data transfer line 33.

  Based on the control of the row selection circuit 31 and the column selection circuit 32, voltage signals can be output from all the pixels included in the imaging region 30. Further, based on the control of the row selection circuit 31 and the column selection circuit 32, a voltage signal can be output from a part of all the pixels included in the imaging region 30. That is, the CMOS imager 6 can read out signals in units of pixels. Therefore, the reading range can be more effectively limited than a charge transfer type CCD (Charge Coupled Device) sensor.

  As described above, the arithmetic processing unit 5 includes the sensor control unit (control unit) 5a, the image processing unit 5b, the signal decoding unit 5c, and the position estimation unit 5d. Each function of the arithmetic processing unit 5 is realized by executing a program stored in the storage unit by a CPU core or the like.

  The sensor control unit 5a sets the address of a pixel that actually reads a signal from the pixels included in the imaging region 30 of the CMOS imager 6 based on the coordinate signal S2. The sensor control unit 5a outputs the address of the pixel from which the signal is read to the CMOS imager 6 as a signal S3. As a result, voltage signals are sequentially output from the designated address pixels from the CMOS imager 6. That is, the sensor control unit 5a causes the CMOS imager 6 to read a voltage signal from pixels in a range corresponding to the incident position of the optical signal incident on the light receiving region 20 of the position detection sensor 3.

  Thereby, the pixel which reads a voltage signal can be limited suitably. That is, it is possible to suppress acquisition of an image that is not used when estimating the whereabouts of the robot 100. Further, the CMOS imager 6 can be driven at a higher speed by limiting the pixels from which the voltage signal is read, compared to the case where the voltage signal is read from all the pixels.

  When all voltage signals are read from all pixels of the CMOS imager 6, it is necessary to selectively designate rows and columns by the row selection circuit 31 and the column selection circuit 32. Therefore, it takes a required time to read out all voltage signals from all pixels. If the time required to read out signals from the pixels becomes longer, the frame rate of the CMOS imager 6 decreases. For this reason, it is impossible to detect a signal that has been pulse-modulated at high speed based on an image acquired by the CMOS imager 6.

  In the present embodiment, the CMOS imager 6 can be driven at a higher speed by making the readout range in which the voltage signal is actually read from the pixel narrower than the imaging range 30. That is, the CMOS imager 6 can acquire an image with higher time resolution. Therefore, even if the optical signal output from the light emitting device 200 is pulse-modulated at a very short time interval, the pulse-modulated signal can be decoded based on the image acquired by the CMOS imager 6. Note that limiting the readout range does not exclude limiting the imaging range. In other words, the present embodiment can also be applied when imaging in a range corresponding to the readout range.

  The image processing unit 5b illustrated in FIG. 2 performs image processing on the image (signal S4) read from the CMOS imager 6. Specifically, the image processing unit 5b executes binarization processing on an image read from the CMOS imager 6 based on a preset threshold value. Thereby, the optical signal incident on the imaging region 30 can be extracted.

  In order to estimate the position, it is not necessary to observe the image acquired by the CMOS imager 6, and it is necessary to determine which part of the imaging region 30 of the CMOS imager 6 the optical signal has entered. As described above, by performing the binarization process on the image read from the CMOS imager 6, it is possible to more easily determine in which part of the imaging region 30 of the CMOS imager 6 the optical signal is incident.

  The signal decoding unit 5c decodes the signal superimposed on the optical signal based on the plurality of images subjected to the image processing by the image processing unit 5b. Here, the identification signal of the light emitting device 200 is superimposed on the optical signal output from the light emitting device 200. By decoding this identification signal, the light emitting device 200 that is outputting the currently received optical signal can be identified. The signal decoding unit 5c may perform signal decoding based on the output of the position detection sensor 3.

  The position estimation unit 5d roughly estimates at which position on the map the robot 100 is based on the identification signal decoded by the signal decoding unit 5c. The position estimation unit 5d detects a position on the imaging region 30 on which the optical signal is incident based on the plurality of images processed by the image processing unit 5b, and based on the detection result, the current location of the robot 100 Is estimated in detail.

  The position estimation unit 5d has map information in advance. In other words, the position estimation unit 5d has a storage area (hard disk, semiconductor memory, etc.) in which map information is stored. The place where the light emitting device 200 is provided is written in advance in this map information. The position estimation unit 5d roughly estimates the position on the map based on the output of the signal decoding unit 5c.

  The position estimation unit 5d detects a position on the imaging region 30 where the optical signal is incident based on the plurality of images subjected to the image processing by the image processing unit 5b. If the incident position of the optical signal on the imaging region 30 is detected, the relative positional relationship between the light emitting device 200 and the imaging unit 50 is obtained. Therefore, it is possible to estimate its own position with respect to the light emitting device 200 based on this positional relationship. By executing both decoding of the signal and detection of the incident position of the optical signal on the imaging surface, the position of the robot on the map can be estimated with high accuracy.

  With reference to FIG. 6, a schematic operation of the position estimation device 60 will be described.

  First, coordinate information is acquired using a position detection sensor (PSD (Position Sensitive Detector)) (S1). When a spot-like optical signal enters the light receiving region 20 of the position detection sensor 3, photocurrents are output as signals S1a to S1d from the divided signal extraction electrodes 21a to 21d. Based on the signals S1a to S1d, the signal processing circuit 4 generates coordinate signals S2a and S2b indicating the incident positions of the optical signals on the light receiving region 20, and outputs them. The coordinate signals S2a and S2b can also be grasped as coordinate information.

  Next, a reading range is set based on the coordinate information (S2). Specifically, the sensor control unit 5a sets the address of a pixel that actually reads a signal from the pixels included in the imaging region 30 of the CMOS imager 6 based on the coordinate signal S2 output from the signal processing circuit 4, A signal S3 indicating the address of the pixel to be read is output to the CMOS imager 6. For example, a plurality of pixel groups in the vicinity of the estimated optical signal incidence position on the imaging surface of the CMOS imager 6 are specified, and the addresses of the pixel groups specified in this way are output to the CMOS imager 6 as a signal S3.

  Next, a signal is output from the pixel at the designated address (S3). In other words, a signal is output from a pixel within the designated readout range. In response to the input of the signal S3, the CMOS imager 6 reads the voltage signal held in the pixel at the designated address and outputs this as a signal S4. It is assumed that the CMOS imager 6 performs signal accumulation and reset of the accumulated signal at predetermined time intervals.

  Next, the acquired image is binarized (S4). Specifically, the image processing unit 5b performs binarization processing on the signal S4 based on a preset threshold value. Thereby, the optical signal incident on the imaging region 30 can be extracted.

  Next, the incident position of the optical signal in the imaging region 30 is specified (S5). Specifically, the position estimation unit 5d detects the position on the imaging region 30 where the optical signal is incident based on a plurality of images subjected to image processing by the image processing unit 5b.

  A method for specifying the incident position of the optical signal will be described with reference to FIG. 7A and 7B show a case where an optical signal is incident on the imaging region 30, and FIGS. 7C and 7D are explanatory diagrams when the optical signal is not incident on the imaging region 30. FIG. 7A and 7C show the readout range R40 set in the imaging region 30. FIG. FIG.7 (b) shows the intensity distribution after binarization between x7b-x7b of Fig.7 (a). FIG.7 (d) shows the intensity distribution after binarization between x7d-x7d of FIG.7 (c). It is assumed that an optical signal from the light emitting device 200 enters the range R1, and noise light enters the range R2.

  The image processing unit 5b takes the difference between FIG. 7B and FIG. As a result, the pattern dp1 corresponding to the incident noise light can be eliminated. This makes it possible to perform position estimation with higher accuracy.

  In the space in which the robot 100 moves, various light sources may be arranged in addition to the light emitting device 200. When the robot 100 is placed outdoors, it is naturally affected by sunlight. However, it is assumed that a light source other than the light emitting device 200 constantly outputs light having a constant intensity at a fixed position. Therefore, as described above, noise light can be suitably eliminated by obtaining the difference between the binary image when the light signal from the light emitting device 200 is input and the binary image when the light signal is not input. it can.

  Returning again to FIG.

  Next, the signal is decoded (S6). Specifically, the signal decoding unit 5c decodes a signal superimposed on the optical signal based on a plurality of images subjected to image processing by the image processing unit 5b. As described above, in the present embodiment, the pixels that actually read signals from the pixels included in the imaging region 30 are limited. As a result, an image can be acquired with high time resolution within a range that is not excessive or insufficient. Therefore, even when the CMOS imager 6 having a relatively large number of pixels is used, signal decoding can be suitably realized. In practice, decoding of the signal is performed by analyzing an image output from the CMOS imager 6 in time series. Note that step S6 may be executed before step S5 described above.

  Next, the whereabouts are estimated (S7). Specifically, the position estimating unit 5d roughly estimates at which position on the map the robot 100 is based on the identification signal decoded by the signal decoding unit 5c. The position estimation unit 5d detects a position on the imaging region 30 on which the optical signal is incident based on the plurality of images processed by the image processing unit 5b, and based on the detection result, the current location of the robot 100 Is estimated in detail.

  In the present embodiment, the sensor control unit 5a sets a reading range in the imaging region 30 of the CMOS imager 6 based on the coordinate signal S2 indicating the incident position of the optical signal in the position detection sensor 3. Then, a signal is output from the CMOS imager 6 limited to pixels within the readout range. Specifically, the sensor control unit 5a informs the CMOS imager 6 of the address (address) of the pixel to be read out and sequentially outputs the voltage signal of the pixel at the address designated by the CMOS imager 6.

  Thereby, the pixel which reads a voltage signal can be limited suitably. That is, it is possible to suppress acquisition of an image that is not used when estimating the whereabouts of the robot 100. Further, the CMOS imager 6 can be driven at a higher speed if the pixels from which the voltage signal is read are limited as compared with the case where the voltage signal is read from all the pixels. That is, the image is acquired by the CMOS imager 6 with higher time resolution. Therefore, even if the optical signal output from the light emitting device 200 is pulse-modulated at a very short time interval, the pulse-modulated optical signal can be decoded based on the image acquired by the CMOS imager 6. In addition, as described above, the influence of background light can be reduced by taking the difference between the binary image when the optical signal is input and the binary image when the optical signal is not input. Note that the image to be subjected to the difference may be an image before binarization.

[Second Embodiment]
Hereinafter, the second embodiment will be described with reference to FIGS. FIG. 8 is a schematic diagram illustrating a schematic configuration of the imaging unit. FIG. 9 is a block diagram illustrating a schematic configuration of the position estimation apparatus. FIG. 10 is a flowchart for explaining the operation of the position estimation apparatus.

  In the present embodiment, a photodiode (PD (Photo Diode)) 7 is used instead of the position detection sensor 3. Even in such a case, as in the first embodiment, the position information used when estimating the position of the robot can be acquired more efficiently than in the past.

  As shown in FIG. 8, the optical signal output from the beam splitter 2 is input to a photodiode (photodetection element) 7.

  As shown in FIG. 9, the optical signal output from the beam splitter 2 is input to the photodiode 7. A photocurrent is output from the photodiode 7 as a signal S10. A signal S10 output from the photodiode 7 is input to the transimpedance circuit 8. The signal S11 output from the transimpedance circuit 8 is input to the sensor control unit 5a of the arithmetic processing unit 5.

  The photodiode 7 is a light receiving element in which a PN junction is formed, and outputs a photocurrent having a value corresponding to the amount of incident light in a reverse biased state. The transimpedance circuit 8 is an analog circuit that converts a photocurrent into a voltage and outputs this voltage as a signal S11. Note that a phototransistor having a PN junction may be used as the photodiode 7.

  In the present embodiment, the sensor control unit 5a detects the timing at which the optical signal is incident on the photodiode 7 based on whether the signal S11 exceeds a preset threshold value. Then, the sensor control unit 5 a drives the CMOS imager 6 in synchronization with the timing when the optical signal is incident on the photodiode 7. In other words, the sensor control unit 5a instructs the CMOS imager 6 to take an image in synchronization with the incident timing of the optical signal detected by the photodiode 7.

  Even if the image on which the optical signal is not copied can be used for background light removal, it cannot be used for specifying the position of the optical signal incident on the imaging region 30. Therefore, there are cases where it is better to reduce the number of images that are not captured with an optical signal or not to acquire the images themselves. In the present embodiment, in view of this point, the timing at which the CMOS imager 6 images is synchronized with the timing detected by the photodiode 7 as described above. In this way, useless images that are not used for position estimation can be eliminated.

  The signal decoding unit 5c decodes the signal superimposed on the optical signal based on the output of the photodiode 7. Further, a comparison circuit may be provided between the transimpedance circuit 8 and the arithmetic processing unit 5 to detect the presence / absence of an optical signal input. In this case, the sensor control unit 5a controls the CMOS imager 6 based on the determination result of the comparison circuit. For example, the sensor control unit 5a instructs the CMOS imager 6 to perform imaging when an H level voltage signal is output from the comparison circuit. The sensor control unit 5a does not instruct the CMOS imager 6 to take an image when an L level voltage signal is output from the comparison circuit.

  Next, the operation of the position estimation device 60 will be described with reference to FIG.

  First, an optical signal is received (S1). Specifically, the photodiode 7 receives an optical signal.

  Next, it is judged whether it is more than a threshold value (S2). Specifically, the sensor control unit 5a determines whether the level of the voltage signal S11 output from the transimpedance circuit 8 is equal to or higher than a preset threshold value.

  If the voltage signal S11 is greater than or equal to the threshold value, an instruction for imaging is given (S3). Specifically, the sensor control unit 5a instructs the CMOS imager 6 to take an image.

  Next, imaging is executed (S4). Specifically, the CMOS imager 6 receives an imaging instruction signal S3 transmitted from the sensor control unit 5a and executes imaging. Then, the CMOS imager 6 outputs the captured image to the arithmetic processing unit 5 as a signal S4.

  Note that steps S5, S6, and S7 in FIG. 10 correspond to the corresponding steps in the first embodiment. Therefore, the overlapping description is omitted.

  Further, as shown in FIG. 10, after step S1, the signal is decoded (S7). Specifically, the signal decoding unit 5 c decodes the signal superimposed on the optical signal based on the output from the photodiode 7. Here, the CMOS imager 6 captures images at a timing synchronized with the input of the optical signal. Therefore, the signal superimposed on the optical signal is decoded based on the output of the photodiode 7 instead of the output of the CMOM sensor 6.

  In this embodiment, the timing when the CMOS imager 6 captures an image is synchronized with the timing detected by the photodiode 7. In this way, useless images that are not used for position estimation can be eliminated.

[Third embodiment]
The third embodiment will be described below with reference to FIGS. FIG. 11 is a block diagram illustrating a configuration of the arithmetic processing unit 5. FIG. 12 is a flowchart for explaining the operation of the threshold value determination unit. Only differences from the first and second embodiments will be described. This embodiment is positioned as a modification of the first and second embodiments.

  In the present embodiment, the arithmetic processing unit 5 includes a threshold value determining unit 5e. The threshold determination unit 5e determines a threshold used for the binarization processing of the image by the image processing unit 5b based on the output value of the position detection sensor 3 or the photodiode 7. By setting the threshold value in this way, it is possible to facilitate the determination of the presence or absence of an optical signal that has entered the imaging region 30. In addition, the influence of background light included in the captured image can be effectively reduced. This is advantageous particularly when spot-like optical signals are detected in an environment where the illuminance of external light is strong. In addition, when the threshold value determination part 5e determines a threshold value, the output light from the light-emitting device 200 shall not be input into the position detection sensor 3 or the photodiode 7. FIG. Further, the output of the position detection sensor 3 is equal to the sum of the photocurrents output from the position detection sensor 3.

  A threshold setting method will be described with reference to FIG.

  First, the incident light intensity is acquired by the position detection sensor 3 or the photodiode 7 (S1).

  Next, a threshold value is determined based on the incident light intensity (S2). Specifically, the threshold value is set according to the voltage level of the voltage signal input to the arithmetic processing unit 5.

  In the present embodiment, the threshold determination unit 5e determines a threshold used for the binarization processing of the image by the image processing unit 5b based on the output value of the position detection sensor 3 or the photodiode 7. By setting the threshold value in this way, it is possible to facilitate the determination of the presence or absence of an optical signal that has entered the imaging region 30. In addition, the influence of background light included in the captured image can be effectively reduced.

  The present invention is not limited to the above-described embodiment. The position estimation device 60 can be applied to an industrial robot in addition to the part robot as shown in FIG. The specific structure of the photosensor is arbitrary. A CCD sensor may be used instead of the CMOS imager 6. The position detection sensor is not limited to the above-described position detection method. The specific configuration of the signal processing circuit is arbitrary. The specific configuration of the arithmetic processing unit 5 is arbitrary. Each function of the arithmetic processing unit 5 may be realized by hardware.

It is a schematic diagram which shows the structure of the movement control system concerning the 1st Embodiment of this invention. It is a block diagram which shows the schematic structure of the position estimation apparatus concerning the 1st Embodiment of this invention. It is a schematic diagram which shows schematic structure of the imaging unit concerning the 1st Embodiment of this invention. It is a mimetic diagram showing a schematic upper surface composition of PSD concerning a 1st embodiment of the present invention. It is a schematic diagram which shows the schematic top surface structure of the CMOS imager concerning the 1st Embodiment of this invention. It is a flowchart for demonstrating operation | movement of the position estimation apparatus concerning the 1st Embodiment of this invention. It is explanatory drawing for demonstrating the identification method of the input light concerning the 1st Embodiment of this invention. It is a schematic diagram which shows schematic structure of the imaging unit concerning the 2nd Embodiment of this invention. It is a block diagram which shows the schematic structure of the position estimation apparatus concerning the 2nd Embodiment of this invention. It is a flowchart for demonstrating operation | movement of the position estimation apparatus concerning the 2nd Embodiment of this invention. It is a block diagram which shows the structure of the arithmetic processing part 5 concerning the 3rd Embodiment of this invention. It is a flowchart for demonstrating operation | movement of the threshold value determination part concerning the 3rd Embodiment of this invention.

Explanation of symbols

300 Movement Control System 100 Robot 60 Position Estimation Device 50 Imaging Unit

DESCRIPTION OF SYMBOLS 1 Optical system 2 Beam splitter 3 Position detection sensor 4 Signal processing circuit 5 Arithmetic processing part 6 CMOS imager 7 Photodiode 8 Transimpedance circuit

5a Sensor control unit 5b Image processing unit 5c Signal decoding unit 5d Position estimation unit 5e Threshold determination unit

20 Light receiving area 21a-21d Signal extraction electrode

10 Entrance window 11 Objective lens

30 Image pickup area 31 Row selection circuit 32 Column selection circuit 33 Data transfer line

Claims (15)

A position information acquisition device that acquires position information based on detection of an optical signal coming from the outside,
Optical branching means for branching the optical signal in the first and second directions;
A light detecting element that receives the optical signal guided in the first direction via the optical branching means;
An imaging device having an imaging surface in which a plurality of pixels are arranged, and receiving the optical signal guided in the second direction via the optical branching means by one or more of the pixels;
A control unit for controlling the timing of the image pickup device takes an image based on the output of the previous SL photodetector,
A position information acquisition device comprising: A position information acquisition device that acquires position information based on detection of an optical signal coming from the outside,
Optical branching means for branching the optical signal in the first and second directions;
A light detecting element that receives the optical signal guided in the first direction via the optical branching means;
An imaging device having an imaging surface in which a plurality of pixels are arranged, and receiving the optical signal guided in the second direction via the optical branching means by one or more of the pixels;
And a read allowed Ru control section signals from some of the plurality of pixels in the imaging device based on an output of the light detection element,
The position information acquisition device , wherein the light detection element is a position detection element that detects an incident position of the optical signal in a light receiving region corresponding to the imaging surface .   The control unit sets a reading range in a part of the imaging surface of the imaging element based on a signal indicating an incident position of the optical signal in the light receiving region output from the light detection element, and The position information acquisition apparatus according to claim 2, wherein a signal is read from the pixels within the reading range. The optical signal in advance is outputted from the light source provided outside, the position information acquisition apparatus according possible to claim 1 or 2, characterized in that signal identifying at least said light emitting sources each other is superimposed.   The position information acquisition apparatus according to claim 4, further comprising a signal decoding unit that decodes a signal superimposed on the optical signal based on an output of the light detection element and / or the imaging element. The light detecting element, the position information acquisition apparatus according to claim 1 or 2, characterized in that a light receiving element for outputting a current having a value corresponding to the incident light intensity.   The control unit includes the imaging element based on a signal indicating input or non-input of the optical signal output from the light receiving element, in all or part of the plurality of pixels included in the imaging surface of the imaging element. The position information acquisition apparatus according to claim 6, wherein the position information acquisition apparatus performs imaging.   The position information acquisition apparatus according to claim 6, wherein the optical signal is output from a light source provided outside in advance, and at least a signal for identifying the light sources is superimposed.   The position information acquisition apparatus according to claim 8, further comprising a signal decoding unit that decodes a signal superimposed on the optical signal based on an output of the light receiving element. A threshold value determination unit for determining a threshold value based on an output from the light detection element;
An image processing unit that performs binarization processing on an image output from the image sensor based on the threshold value determined by the threshold value determination unit;
The position information acquisition apparatus according to claim 1, further comprising:   The position information acquisition apparatus according to claim 1, wherein the optical branching unit is a beam splitter that guides a part of the optical signal to each of the light detection element and the imaging element. A position estimation device for estimating a position in space based on detection of an optical signal coming from the outside,
Optical branching means for branching the optical signal in the first and second directions;
A light detecting element that receives the optical signal guided in the first direction via the optical branching means;
An imaging device having an imaging surface in which a plurality of pixels are arranged, and receiving the optical signal guided in the second direction via the optical branching means by one or more of the pixels;
A control unit for controlling the timing of the image pickup device takes an image based on the output of the previous SL photodetector,
A position estimation unit that detects an incident position of the optical signal in the imaging surface based on an image output from the imaging element, and estimates a location in the space based on the detection result;
A position estimation apparatus comprising: A position estimation device for estimating a position in space based on detection of an optical signal coming from the outside,
Optical branching means for branching the optical signal in the first and second directions;
A light detecting element that receives the optical signal guided in the first direction via the optical branching means;
An imaging device having an imaging surface in which a plurality of pixels are arranged, and receiving the optical signal guided in the second direction via the optical branching means by one or more of the pixels;
A plurality of said read allowed Ru control section some signals from pixels in the imaging device based on an output of the light detection element,
A position estimation unit that detects an incident position of the optical signal in the imaging surface based on an image output from the imaging element, and estimates a location in the space based on the detection result;
Equipped with a,
The position estimation device , wherein the light detection element is a position detection element that detects an incident position of the optical signal in a light receiving region corresponding to the imaging surface . The position estimating unit specifies an incident position of the optical signal in the imaging surface based on obtaining a difference between an image in which the optical signal is copied and an image in which the optical signal is not copied. The position estimation apparatus according to claim 12 or 13 . A mobile body comprising the position information acquisition apparatus according to claim 1 or 2 or the position estimation apparatus according to claim 12 or 13 .

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