Detection device, detection method, and program

Abstract

The goal is to achieve both the suppression of sensor lifespan reduction due to heat generation and the maintenance of detection accuracy for the target object. [Solution] The detection device 10 includes a CPU 11 that detects a target by controlling a light-emitting element 21 that irradiates the target with light and a light-receiving element 22 that receives the light reflected by the target. The CPU 11 acquires temperature information related to the temperature of the light-emitting element 21 and the detection status of the target, and determines the amount of light emitted by the light-emitting element 21 in a predetermined unit time based on the detection accuracy according to the detection status and the temperature information.

Description

Technical Field

[0001] The present invention relates to a detection device, a detection method, and a program.

Background Art

[0002] In recent years, with the development of IoT (Internet of Things) technology, various 3D sensors, which are sensor devices capable of measuring distances in a three-dimensional space, have become widespread.

[0003] As a typical 3D sensor, there is a ToF (Time of Flight) sensor that acquires the time from when a light-emitting element such as a laser or an LED (Light Emitting Diode) emits light until the light is reflected by a detection target and received by a light-receiving element, and calculates the distance to the detection target based on the time. The detection accuracy of the ToF sensor increases as the light emission amount of the light-emitting element increases. On the other hand, the light-emitting element has a problem that it generates heat and its lifespan is shortened as the light emission amount increases.

[0004] Therefore, for example, Patent Document 1 describes a depth image acquisition device that increases the overall light emission amount by providing a plurality of light-emitting elements and improves the distance measurement accuracy even at long distances. Also, for example, Patent Document 2 describes a distance measurement imaging device that improves the distance measurement accuracy by performing correction using peripheral pixels.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] This invention has been made in view of the above-mentioned problems, and aims to achieve both the suppression of shortening the sensor's lifespan due to heat generation and the maintenance of detection accuracy of the target object. [Means for solving the problem]

[0007] To solve the above problems, the detection device according to the present invention is The system includes a control unit that detects a target by controlling a light-emitting element that irradiates the target with light and a light-receiving element that receives the light reflected by the target. The control unit acquires temperature information relating to the temperature of the light-emitting element and the detection status of the target, and determines the amount of light emitted by the light-emitting element in a predetermined unit of time based on the detection accuracy according to the detection status and the temperature information. [Effects of the Invention]

[0008] According to the present invention, it is possible to suppress the shortening of the sensor's lifespan due to heat generation while maintaining the detection accuracy of the target object. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of an image projection system. [Figure 2] This is an example of gestures that an operator can make to a video projection system. [Figure 3] This is a block diagram showing the functional configuration of a video projection system. [Figure 4] This is a schematic diagram showing the detection area set in the configuration data. [Figure 5] This flowchart shows the control procedure for the light emission control process. [Modes for carrying out the invention]

[0010] Hereinafter, an embodiment of the present invention applied to a projection device will be described in detail with reference to the drawings.

[0011] Figure 1 is a schematic diagram showing an example of applying the detection device 10 according to the present invention to the video projection system 1. The video projection system 1 comprises a detection device 10, a ToF sensor 20, and a projection device 30. The detection device 10 is wirelessly or wiredly connected to the ToF sensor 20 and the projection device 30, enabling the transmission and reception of data such as control signals and image data between the detection device 10 and the ToF sensor 20 and the projection device 30.

[0012] The detection device 10 of the video projection system 1 detects gestures made by, for example, the operator 80 with their hands or fingers by irradiating and receiving light with the ToF sensor 20, and controls the operation of the projection device 30, such as the projection of spatial images V or the changing of various settings, according to the detected gesture. More specifically, the ToF sensor 20 transmits image data acquired by irradiating the hand or fingers of the operator 80, who is positioned directly in front of it, to the detection device 10. The detection device 10 analyzes the image data received from the ToF sensor 20 to detect the hand or fingers of the operator 80 and determines whether the operator 80 has performed a predetermined gesture at predetermined coordinates with their hand or fingers. When the detection device 10 determines that the operator 80 has performed the predetermined gesture, it transmits a predetermined control signal to the projection device 30 and controls the projection device 30 to perform processing corresponding to the gesture at the detected coordinates.

[0013] This allows for intuitive operation of the spatial image V by, for example, the operator 80 performing operations such as tapping by bringing one finger (e.g., index finger) close to the spatial image V, two-finger tapping by bringing two fingers (e.g., index finger and middle finger) close to the spatial image V, or pinching out by moving two fingers (e.g., thumb and index finger) away from the spatial image V in opposite directions, as shown in Figure 2.

[0014] Figure 3 is a block diagram showing the functional configuration of the video projection system 1. The detection device 10 of the image projection system 1 includes a CPU (Central Processing Unit) 11, a RAM (Random Access Memory) 12, a storage unit 13, an operation unit 14, a display unit 15, a communication unit 16, a bus 17, and the like. Each part of the detection device 10 is connected via the bus 17. The detection device 10 is a notebook PC in this embodiment, but is not limited thereto, and may be, for example, a desktop PC, a cloud server, a smartphone, or a tablet-type terminal.

[0015] The CPU 11 is a processor that reads and executes the program 131 stored in the storage unit 13 and controls the operation of the detection device 10 by performing various arithmetic processes. The CPU 11 functions as a control unit by executing the program 131 to execute various processes. Note that the detection device 10 may have a plurality of processors (such as a plurality of CPUs), and the plurality of processes executed by the CPU 11 in this embodiment may be executed by the plurality of processors. In this case, the plurality of processors may be involved in common processes, or alternatively, the plurality of processors may independently execute different processes in parallel.

[0016] The RAM 12 provides a working memory space for the CPU 11 and stores temporary data.

[0017] The storage unit 13 is a non-temporary recording medium readable by the CPU 11 as a computer, and stores the program 131 and various data. The storage unit 13 includes, for example, a non-volatile memory such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive). The program 131 is stored in the storage unit 13 in the form of program code readable by a computer. The data stored in the storage unit 13 includes captured image data 132, which is image data of an IR (InfraRed) image and a Depth image received from the ToF sensor 20, and setting data 133 used in the light emission amount control process described later.

[0018] The setting data 133 is set based on the area where the detection target is located, that is, the depth, namely the distance from the ToF sensor 20. In the setting data 133, as shown in FIG. 4, a gesture detection area 133a for detecting the gesture of the hand or finger of the operator 80 and a person detection area 133b for detecting the operator 80 are set in order from the vicinity of the ToF sensor 20. In the setting data 133, the gesture detection area 133a is set, for example, in the range of a depth of 20 cm to 1 m. Also, in the setting data 133, the person detection area 133b is set, for example, in the range of a depth of 1 m to 2 m. In this configuration, 1 m is the first value and 2 m is the second value. Note that the numerical settings related to the ranges of such areas may be arbitrarily changed by the administrator of the detection device 10, for example, by operating the operation unit 14.

[0019] The operation unit 14 has at least one of a touch panel provided overlapping the display screen of the display unit 15, a pointing device such as a physical button, a mouse, and an input device such as a keyboard, and outputs operation information corresponding to an input operation to the CPU 11.

[0020] The display unit 15 includes a display device such as a liquid crystal display, and performs various displays on the display device according to a display control signal from the CPU 11.

[0021] The communication unit 16 is composed of a network card or a communication module, etc., and transmits and receives data according to a predetermined communication standard between the ToF sensor 20 and the projection device 30.

[0022] The ToF sensor 20 includes a light emitting element 21 that irradiates infrared light toward the outside of the video projection system 1, a light receiving element 22 that receives the infrared light irradiated by the light emitting element 21 and reflected by the detection target, and a known temperature sensor 23 that acquires the temperature information of the light emitting element 21. The CPU 11 of the detection device 10 causes the ToF sensor 20 to irradiate the detection target with infrared light from the light-emitting element 21, and the photodetector 22 receives the infrared light reflected from the detection target. The CPU 11 then calculates the depth of the detection target based on the time from irradiation to reception and generates a depth image. The CPU 11 also generates an IR image based on the intensity of the infrared light received by the photodetector 22. The light-emitting element 21 and the photodetector 22 may be provided as an integrated unit or separately, as long as they can capture the detection target.

[0023] The CPU 11 sets the detection accuracy of the ToF sensor 20 based on the detection status, and controls the amount of light emitted by the light-emitting element 21 based on the set detection accuracy and the temperature information of the light-emitting element 21 obtained from the temperature sensor 23. In this embodiment, the CPU 11 controls the amount of light emitted by the light-emitting element 21 by controlling the number of times the light-emitting element 21 irradiates infrared light in a predetermined unit time. Note that the method of controlling the amount of light emitted by the light-emitting element 21 by the CPU 11 is not limited to controlling the number of times the light-emitting element 21 irradiates infrared light in a predetermined unit time, but may also be based on, for example, the irradiation time of infrared light by the light-emitting element 21 in a predetermined unit time, i.e., the irradiation ratio. In this embodiment, the detection status is the distance to the detection target, i.e., the area where the detection target is located. In this embodiment, the temperature information of the light-emitting element 21 is the temperature of the light-emitting element 21.

[0024] For example, if the ToF sensor 20 detects an object in the gesture detection area 133a, it is highly likely that the object is the hand or fingers of the operator 80. If the object is the hand or fingers of the operator 80, the detection device 10 needs to detect a gesture with fine movements of the hand or fingers. Therefore, the CPU 11 sets the detection accuracy of the ToF sensor 20 to the first detection accuracy, which is the highest possible accuracy. When the detection accuracy of the ToF sensor 20 is set to the first detection accuracy, the CPU 11 controls the light-emitting element 21 to emit infrared light at a first emission amount, which is the largest emission amount that can be set, regardless of the temperature information of the light-emitting element 21 obtained from the temperature sensor 23.

[0025] On the other hand, if a target is detected in the person detection area 133b, which is further away from the gesture detection area 133a, it is highly likely that the target is the operator 80. If the target is the operator 80, it is larger than a hand or finger, so detection is possible if a predetermined amount of data can be obtained. Therefore, compared to when a target is detected in the gesture detection area 133a, the detection accuracy can be relatively lower, and the CPU 11 sets the detection accuracy of the ToF sensor 20 to a second detection accuracy, which is lower than the first detection accuracy.

[0026] As described above, increasing the light emission of the light-emitting element 21 generates heat and shortens its lifespan. On the other hand, even if the object to be detected does not require high-precision detection, it is preferable to perform high-precision detection as long as the heat generation is acceptable. Therefore, when the detection accuracy of the ToF sensor 20 is set to the second detection accuracy, the CPU 11 controls the amount of light emitted by the light-emitting element 21 based on the temperature information of the light-emitting element 21 obtained from the temperature sensor 23.

[0027] In detail, the CPU 11 controls whether to relatively decrease or increase the amount of light emitted by the light-emitting element 21 depending on whether the temperature information of the light-emitting element 21 (for example, the temperature of the light-emitting element 21) obtained from the temperature sensor 23 is above a predetermined first temperature (for example, 80°C in this embodiment). With this configuration, the detection device 10 can detect the target object with the highest possible accuracy while suppressing the operation of the ToF sensor 20 at high temperatures.

[0028] More specifically, for example, when the ToF sensor 20 detects a target in the person detection area 133b, the CPU 11 determines whether the temperature information of the light-emitting element 21 obtained from the temperature sensor 23 is equal to or greater than a first temperature. If the temperature information of the light-emitting element 21 is less than the first temperature, increasing the amount of light emitted does not pose a risk of shortening the lifespan of the light-emitting element 21 due to heat generation. Therefore, the CPU 11 controls the light-emitting element 21 to have the same first amount of light emitted as when a target is detected in the gesture detection area 133a (for example, 100,000 infrared light irradiations). On the other hand, if the temperature information of the light-emitting element 21 obtained from the temperature sensor 23 is above the first temperature, increasing the amount of light emitted and further heating the light-emitting element 21 would risk shortening the lifespan of the light-emitting element 21 due to heat generation. Therefore, the CPU 11 controls the light-emitting element 21 to emit a second amount of light that is less than the first amount of light emitted (for example, 30,000 times of infrared light irradiation).

[0029] In the above example, the ToF sensor 20 is equipped with a temperature sensor 23 to measure the temperature of the light-emitting element 21, but this is not the only example. For example, the temperature sensor 23 may be located near the light-emitting element 21 to measure the temperature in the vicinity of the light-emitting element 21. In particular, as shown in Figure 1, if the detection device 10 is located near the ToF sensor 20, the detection device 10 may be equipped with a temperature sensor 23.

[0030] The projection device 30 shown in Figure 1 projects (forms) a spatial image V onto the space of the gesture detection area 133a by irradiating projection light with a high directivity and intensity distribution corresponding to the image data of the spatial image V. Specifically, the projection device 30 includes a light source, a display element such as a digital micromirror element that adjusts the intensity distribution of the light output from the light source to form a light image, and a group of projection lenses that focus the light image formed by the display element and project it as a spatial image V. The projection device 30 changes the spatial image V to be projected and changes settings related to the projection mode (brightness, color tone, etc.) according to a control signal transmitted from the detection device 10 that detects the gesture of the operator 80.

[0031] Next, the light emission control process by the detection device 10 will be described. Figure 5 is a flowchart showing the flow of the light emission control process. The light emission control process is executed, for example, when the video projection system 1 starts operating, through the cooperation of the CPU 11 of the detection device 10 and the program 131 stored in the memory unit 13.

[0032] First, the CPU 11 acquires IR image and depth image data by irradiating the detection target with infrared light using the ToF sensor 20 (step S1). The CPU 11 also acquires the temperature of the light-emitting element 21 from the temperature sensor 23 as temperature information for the light-emitting element 21 (step S2). The CPU 11 also acquires the setting data 133 stored in the memory unit 13 (step S3). Note that the order in which these steps S1 to S3 are performed is not limited to the above and may be any order.

[0033] In step S4, the CPU 11 determines whether the detection target is located in the gesture detection area 133a based on the depth image acquired in step S1 (step S4). If the CPU determines that the object to be detected is located in the gesture detection area 133a (step S4; YES), the CPU 11 sets the detection accuracy of the detection device 10 to the highest first detection accuracy. If the detection accuracy is set to the first accuracy, the CPU 11 sets the light emission amount of the light-emitting element 21 to the first light emission amount (step S5).

[0034] If the CPU determines that the target is not located in the gesture detection area 133a (step S4; NO), the CPU 11 determines whether or not the target is located in the person detection area 133b (step S6). If the CPU determines that the target is located in the person detection area 133b (step S6; YES), the CPU 11 sets the detection accuracy of the detection device 10 to a second detection accuracy that is lower than the first detection accuracy. Then, the CPU 11 determines whether the temperature information of the light-emitting element 21 acquired in step S2 is equal to or greater than the first temperature (step S7).

[0035] If the detection accuracy of the detection device 10 is the second detection accuracy and the temperature information of the light-emitting element 21 is less than the first temperature (step S7; NO), the CPU 11 sets the light emission amount of the light-emitting element 21 to the first light emission amount (step S8). If the detection accuracy of the detection device 10 is the second detection accuracy and the temperature information of the light-emitting element 21 is equal to or greater than the first temperature (step S7; YES), the CPU 11 sets the light emission amount of the light-emitting element 21 to a second light emission amount which is less than the first light emission amount (step S9).

[0036] If the CPU determines that the target is not located in the person detection area 133b (step S6; NO), the CPU 11 sets the detection accuracy of the detection device 10 to a third detection accuracy that is lower than the second detection accuracy. The CPU 11 also determines whether the temperature information of the light-emitting element 21 acquired in step S2 is at or above a second temperature (for example, 22°C in this embodiment) that is lower than the first temperature (step S10).

[0037] If the detection accuracy of the detection device 10 is the third detection accuracy and the temperature information of the light-emitting element 21 is less than the second temperature (step S10; NO), the CPU 11 sets the light emission amount of the light-emitting element 21 to the second light emission amount (step S11). If the detection accuracy of the detection device 10 is the third detection accuracy and the temperature information of the light-emitting element 21 is equal to or greater than the second temperature (step S10; YES), the CPU 11 sets the light emission amount of the light-emitting element 21 to a third light emission amount which is less than the second light emission amount (step S12).

[0038] If the target cannot be detected in the gesture detection area 133a or the person detection area 133b, the amount of light emitted by the light-emitting element 21 should be a third amount of light emitted, which is the minimum amount of light emitted to detect a person and is lower than the first and second amounts of light emitted. On the other hand, as described above, even if the target does not require high-precision detection, it is preferable to perform high-precision detection as long as heat generation is acceptable. Therefore, the CPU 11 determines and controls whether the amount of light emitted by the light-emitting element 21 should be a third amount of light emitted or a second amount of light emitted, which is greater than the third amount of light emitted, depending on whether the temperature information of the light-emitting element 21 is below the second temperature.

[0039] If the light emission amount of the light-emitting element 21 is set in any of steps S5, S8, S9, S11, or S12, the CPU 11 determines whether or not it has received an instruction to terminate the operation of the video projection system 1 (step S13). If it has not received an instruction to terminate the operation of the video projection system 1 (step S13; NO), it proceeds to step S4 and performs light emission amount control again based on the position and temperature information of the detected target. If it has received an instruction to stop the operation of the video projection system 1 (step S13; YES), it terminates the light emission amount control process.

[0040] As described above, the detection device 10 according to this embodiment includes a CPU 11 that detects a target by controlling a light-emitting element 21 that irradiates the target with light and a light-receiving element 22 that receives light reflected from the target. The CPU 11 acquires temperature information related to the temperature of the light-emitting element 21 and the detection status of the target, and determines the amount of light emitted by the light-emitting element 21 in a predetermined unit time based on the detection accuracy according to the detection status and the temperature information. In this way, since the CPU 11 determines the amount of light emitted by the light-emitting element 21 based on both the detection accuracy and the temperature information, it is possible to suppress the shortening of the lifespan caused by heat generation of the light-emitting element 21 and to detect the target with high accuracy.

[0041] Furthermore, the CPU 11 of this embodiment acquires the detection status, including the distance to the target to be detected. If the distance to the target to be detected is within a first value, it sets the first detection accuracy as the detection accuracy from among the first detection accuracy, the second detection accuracy lower than the first detection accuracy, and the third detection accuracy lower than the second detection accuracy. If the distance to the target to be detected is greater than or equal to the first value and within a second value greater than the first value, it sets the second detection accuracy as the detection accuracy. Therefore, the detection accuracy is set to be higher when the target to be detected is closer, enabling high-precision detection of fine movements of the target to be detected in the vicinity of the ToF sensor 20.

[0042] Furthermore, in this embodiment, if the acquired temperature information is above a predetermined value and the detection accuracy is the first detection accuracy, the CPU 11 determines the first light emission amount from among the first light emission amount, the second light emission amount which is less than the first light emission amount, and the third light emission amount which is less than the second light emission amount. Therefore, when high-precision detection of the target is required, the target can be detected with high precision.

[0043] Furthermore, in this embodiment, if the acquired temperature information is above a predetermined value and the detection accuracy is the second detection accuracy, the CPU 11 determines the second light emission amount as the light emission amount from among the first light emission amount, the second light emission amount which is less than the first light emission amount, and the third light emission amount which is less than the second light emission amount. Therefore, in cases where high-precision detection of the object to be detected is not required, and there is a risk of the light-emitting element 21 generating heat, priority is given to suppressing the heat generation of the light-emitting element 21, thereby suppressing the shortening of the lifespan caused by heat generation.

[0044] Furthermore, in this embodiment, if the acquired temperature information is less than a predetermined value and the detection accuracy is the second detection accuracy, the CPU 11 determines the first light emission amount as the light emission amount from among the first light emission amount, the second light emission amount which is less than the first light emission amount, and the third light emission amount which is less than the second light emission amount. Therefore, even if high-precision detection of the object to be detected is not required, the object to be detected can be detected with high precision if there is no risk of the light-emitting element 21 generating heat.

[0045] Furthermore, the CPU 11 in this embodiment acquires the temperature near the light-emitting element 21 as temperature information. Therefore, the present invention is not limited to cases where the temperature sensor 23 is provided on the ToF sensor 20, and can be applied to various configurations.

[0046] Furthermore, the CPU 11 in this embodiment controls the amount of light emitted by controlling the number of irradiations or the ratio of irradiation time of the light-emitting element 21 in a predetermined unit time. Therefore, the present invention can be applied to a detection device 10 in which the CPU 11 controls the amount of light emitted from the light-emitting element 21 in various ways.

[0047] Furthermore, in the detection method according to this embodiment, the detection device 10 includes a CPU 11 that detects a target by controlling a light-emitting element 21 that irradiates the target with light and a light-receiving element 22 that receives light reflected from the target. The CPU 11 acquires temperature information related to the temperature of the light-emitting element 21 and the detection status of the target, and determines the amount of light emitted by the light-emitting element 21 in a predetermined unit time based on the detection accuracy according to the detection status and the temperature information. In this way, since the CPU 11 determines the amount of light emitted by the light-emitting element 21 based on both the detection accuracy and the temperature information, it is possible to suppress the shortening of the lifespan caused by heat generation of the light-emitting element 21 and to detect the target with high accuracy.

[0048] Furthermore, the program 131 according to this embodiment causes the CPU 11, which acts as a computer that detects a target by controlling a light-emitting element 21 that irradiates the target with light and a light-receiving element 22 that receives light reflected from the target, to function as a control unit that acquires temperature information related to the temperature of the light-emitting element 21 and the detection status of the target, and determines the amount of light emitted by the light-emitting element 21 in a predetermined unit time based on the detection accuracy according to the detection status and the temperature information. In this way, since the CPU 11 determines the amount of light emitted by the light-emitting element 21 based on both the detection accuracy and the temperature information, it is possible to suppress the shortening of the lifespan caused by heat generation of the light-emitting element 21 and to detect the target with high accuracy.

[0049] Furthermore, although several embodiments of the present invention have been described, the scope of the present invention is not limited to the embodiments described above, but includes the scope of the invention as described in the claims and its equivalents. For example, Figure 1 illustrates a configuration in which the detection device 10 is provided inside the video projection system 1, but it is not limited to this. That is, the detection device 10, which includes the CPU 11, may be separate from the video projection system 1 and the storage unit 13.

[0050] Furthermore, although the above example illustrates a configuration in which the CPU 11 determines the amount of light emitted by the light-emitting element 21 in steps depending on whether the detection target is located in one of the areas, the CPU 11 is not limited to this, and the CPU 11 may linearly determine the amount of light emitted by applying the acquired depth value of the detection target to a predetermined formula. Examples of predetermined formulas for setting the amount of light emitted based on the acquired depth value of the detection target include the following formulas (1) to (3). Luminous emission = (Maximum luminous emission) × (Depth value / Maximum detectable depth) ... (1) Luminous emission = (Maximum luminous emission) × (Minimum detectable depth / Depth value) ... (2) Luminous emission = (Maximum luminous emission) - (Maximum luminous emission × (Depth value / Maximum detectable depth)) ... (3) Formula (1) is a calculation formula used, for example, when the video projection system 1 is fixed at a distance from the object to be detected and high-precision detection is required. On the other hand, formulas (2) and (3), as described above, are calculation formulas used when the distance to the object to be detected is short and high-precision detection is required.

[0051] Furthermore, although the above example illustrates a configuration in which the CPU 11 sets the amount of light emitted by the light-emitting element 21 based on both the area where the detection target is located and the temperature information of the light-emitting element 21 obtained from the temperature sensor 23, the CPU 11 may also determine the amount of light emitted based only on the temperature information of the light-emitting element 21 obtained from the temperature sensor 23. For example, the following equation (4) can be given as a calculation formula for setting the amount of light emitted based on the temperature of the light-emitting element 21 obtained from the temperature sensor 23. Light output = (Maximum light output) - (Maximum light output × (Sensor temperature / Maximum allowable temperature)) ... (4)

[0052] Similarly, the CPU 11 may control the amount of light emitted based only on the area where the detected object is located, such as setting a first light emission amount when the detected object is located in the gesture detection area 133a, and a second light emission amount when the detected object is located in the person detection area 133b.

[0053] Furthermore, although the above example illustrates a configuration in which the setting data 133 contains the ranges of two areas, the gesture detection area 133a and the person detection area 133b, the configuration is not limited to this, and the setting data 133 may contain the ranges of one or more areas.

[0054] Furthermore, while the above example illustrates a configuration in which the detection status is the area where the target is located, and the CPU 11 sets the detection accuracy of the detection device 10 according to the area where the target is located, the system is not limited to this configuration. The CPU 11 may also set the detection accuracy of the detection device 10 according to the target based on a pre-configured table. For example, if the set detection target is only hand movements and does not include finger movements, then high-precision detection of the target is not required compared to cases where finger movements need to be detected. Therefore, in such cases, even if a target is detected in the gesture detection area 133a, the system may be configured to set the detection precision to the second level. Also, for example, if the set detection target is a car instead of a person, the system may be configured to set the detection precision to the second or third level even if the target is detected.

[0055] Furthermore, while the above states that if a target is detected in the gesture detection area 133a, it is highly likely that the target is a hand or finger, and if a target is detected in the person detection area 133b, it is highly likely that the target is the operator 80, it is also possible that the operator 80 may be detected in the gesture detection area 133a, or that the operator 80's hand or finger may be detected in the person detection area 133b. Therefore, the CPU 11 may perform known image analysis processing on the captured image data 132, determine whether the target is a hand or finger according to the feature quantities, and suppress the amount of light emitted by the light-emitting element 21 if a hand or finger is not detected. If a hand or finger is detected, the detection accuracy of the detection device 10 may be set to a higher value.

[0056] Furthermore, while the above example illustrates a configuration in which the CPU 11 compares the temperature information of the light-emitting element 21 measured by the temperature sensor 23 with a preset first temperature or second temperature, the system is not limited to this configuration. Not only the light-emitting element 21, but also its peripheral devices are affected by temperature. Therefore, the CPU 11 may also be configured to acquire the ambient temperature and set the first and second temperatures based on that ambient temperature.

[0057] Furthermore, a cooling fan to suppress heat generation of the light-emitting element 21 by blowing air may be provided near the ToF sensor 20. The CPU 11 may then control the rotation speed of the cooling fan based on the temperature information of the light-emitting element 21 obtained from the temperature sensor 23. In addition, the CPU 11 may control the rotation speed of the cooling fan to increase when the light emission amount of the light-emitting element 21 is set to a high value. [Explanation of Symbols]

[0058] 10...Detection device, 11...CPU (control unit), 21...Light-emitting element, 22...Photodetector

Claims

1. The system includes a control unit that detects the target by controlling a light-emitting element that irradiates light onto the target and a light-receiving element that receives the light reflected by the target. The control unit is a detection device that acquires temperature information relating to the temperature of the light-emitting element and the detection status of the object to be detected, and determines the amount of light emitted by the light-emitting element in a predetermined unit time based on the detection accuracy according to the detection status and the temperature information.

2. The detection device according to claim 1, wherein the control unit acquires the detection status including the distance to the object to be detected, sets a first detection accuracy as the detection accuracy when the distance to the object to be detected is within a first value, and sets a second detection accuracy lower than the first detection accuracy as the detection accuracy when the distance to the object to be detected is greater than the first value and within a second value greater than the first value.

3. The detection device according to claim 2, wherein the control unit sets a third detection accuracy lower than the second detection accuracy as the detection accuracy when the distance to the object to be detected is greater than the second value.

4. The detection device according to claim 2, wherein the control unit determines the first amount of light emitted from a first amount of light emitted and a second amount of light emitted less than the first amount of light emitted, when the detection accuracy is the first detection accuracy and the acquired temperature information is greater than or equal to a predetermined value.

5. The detection device according to claim 2, wherein the control unit determines the second amount of light emission, which is less than the first amount of light emission, as the amount of light emission, when the detection accuracy is the second detection accuracy and the acquired temperature information is greater than or equal to a predetermined value.

6. The detection device according to claim 2, wherein the control unit determines the first amount of light emission as the amount of light emission from among a first amount of light emission and a second amount of light emission that is less than the first amount of light emission, when the detection accuracy is the second detection accuracy and the acquired temperature information is less than a predetermined value.

7. The detection device according to claim 2, wherein the control unit determines the first amount of light emission as the amount of light emission from among a first amount of light emission and a second amount of light emission that is less than the first amount of light emission, when the detection accuracy is the second detection accuracy and the acquired temperature information is less than a predetermined value.

8. The detection device according to claim 3, wherein the control unit determines the third amount of light emission as the amount of light emission from among a first amount of light emission, a second amount of light emission less than the first amount of light emission, and a third amount of light emission less than the second amount of light emission.

9. The detection device according to claim 3, wherein the control unit determines the second amount of light emission, which is less than the first amount of light emission, as the amount of light emission, when the detection accuracy is the third detection accuracy and the acquired temperature information is less than a predetermined value, wherein the control unit determines the second amount of light emission, which is less than the first amount of light emission, as the amount of light emission.

10. The detection device according to any one of claims 1 to 9, wherein the control unit acquires the temperature near the light-emitting element as temperature information.

11. The detection device according to any one of claims 1 to 9, wherein the control unit controls the amount of light emitted by controlling the number of irradiations or the ratio of irradiation time of the light-emitting element in a predetermined unit time.

12. A detection method using a detection device that detects a target by controlling a light-emitting element that irradiates the target with light and a light-receiving element that receives the light reflected from the target, A detection method comprising a control step of acquiring temperature information relating to the temperature of the light-emitting element and the detection status of the object to be detected, and determining the amount of light emitted by the light-emitting element in a predetermined unit time based on the detection accuracy according to the detection status and the temperature information.

13. A computer for a detection device that detects a target by controlling a light-emitting element that irradiates light onto the target and a light-receiving element that receives the light reflected from the target, A program that acquires temperature information relating to the temperature of the light-emitting element and the detection status of the object to be detected, and functions as a control unit that determines the amount of light emitted by the light-emitting element in a predetermined unit time based on the detection accuracy according to the detection status and the temperature information.

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