JP2022074953A - Optical device - Google Patents

Abstract

To determine dew condensation regardless of ambient brightness.SOLUTION: A control part 22 starts light emission by a laser light projecting part 11 (step S11), and measures a temperature and humidity of air of an internal space B1 of own machine, and a temperature of an inner surface 151 of a light projecting and receiving window 15 (step S12). A distance measuring part 21 measures a distance measuring value and a light quantity value (step S13). The control part 22 determines whether or not there is dew condensation on the light projecting and receiving window 15, based on the measured distance measuring value and light quantity value (step S14). When it determines whether there is not dew condensation, the control part 22 calculates a dew condensation index, and determines where or not the calculated dew condensation index is equal to or more than a threshold (step S15). When it determines there is the dew condensation in the step S14 (YES), and the dew condensation index is equal to or more than the threshold in the step S15 (YES), the control part 22 controls a heater driver 25 and heats the light projecting and receiving window 15.SELECTED DRAWING: Figure 3

Description

The present invention relates to a technique for reducing dew condensation.

As a technique for reducing dew condensation, Patent Document 1 describes that when an image of a window taken by a camera is analyzed and it is determined that the window is likely to be fogged or the window is fogged, the window is heated by a heater. The technology is disclosed.

Japanese Unexamined Patent Publication No. 2019-004254

When the determination of dew condensation is performed based on the image of the window taken as in the technique of Patent Document 1, if the surroundings are dark, the image of the window may become dark and the determination of dew condensation may not be possible.
In view of the above background, an object of the present invention is to determine dew condensation regardless of the ambient brightness.

In order to solve the above-mentioned problems, the present invention heats the light emitting / receiving window when it is determined that there is dew condensation on the light emitting / receiving window of the distance image sensor based on the distance measurement value of the distance image sensor of the coaxial optical system. The optical device is provided as the first aspect.

According to the optical device of the first aspect, dew condensation can be determined regardless of the ambient brightness.

In the optical device of the first aspect described above, the configuration in which it is determined that there is dew condensation on the light emitting / receiving window when the distance measurement value within a predetermined range is measured may be adopted as the second aspect.

According to the optical device of the second aspect, it is possible to determine the presence or absence of dew condensation if there is only the distance measurement value of each pixel included in the distance image.

In the optical device of the first aspect described above, when the pixels whose distance measurement values within a predetermined range are measured are adjacent or close to each other by a predetermined number or more within a predetermined distance, it is determined that there is dew condensation on the light emitting / receiving window. , May be adopted as the third aspect.

According to the optical device of the third aspect, it is possible to suppress erroneous determination when an error occurs in the distance measurement value due to the influence of disturbance or the like.

In the optical device according to any one of the first to third aspects, the presence or absence of dew condensation in the light emitting / receiving window is determined based on the light quantity value measured by the distance image sensor in addition to the distance measuring value. It may be adopted as a fourth aspect.

According to the optical device of the fourth aspect, the accuracy of the determination of dew condensation can be improved as compared with the case where the determination is performed using only the distance measurement value.

In the optical device of the fourth aspect described above, when the distance measurement value within a predetermined range is measured and the light intensity value of the pixel to which the distance measurement value is measured is within the predetermined range, dew condensation occurs on the light emitting / receiving window. The configuration of determining that there is may be adopted as the fifth aspect.

According to the optical device of the fifth aspect, the accuracy of the determination of dew condensation can be improved as compared with the case where the determination is performed using only the distance measurement value.

In the optical device of the fourth aspect described above, when the distance measurement value within a predetermined range is measured and the pixels for which the light intensity value within the predetermined range is measured are adjacent or close to each other by a predetermined number or more within a predetermined distance. A configuration in which it is determined that there is dew condensation on the light receiving / receiving window may be adopted as the sixth aspect.

According to the optical device of the sixth aspect, it is possible to suppress erroneous determination when an error occurs in the distance measurement value or the light amount value in pixel units due to the influence of disturbance or the like.

In the optical device according to any one of the first to sixth aspects, the seventh aspect is to determine the presence or absence of dew condensation on the light emitting / receiving window based on the measured values of the pixels in the predetermined region of the distance image sensor. May be adopted as.

According to the optical device of the seventh aspect, the load of the determination process can be reduced.

In the optical device of any one of the first to seventh aspects described above, the dew condensation in the light emitting / receiving window calculated based on the measured values of the temperature and humidity of the air in the own machine and the measured values of the temperature of the light receiving / receiving window. An eighth aspect may be adopted in which the light emitting / receiving window is heated when the index of susceptibility to generation is equal to or higher than a predetermined threshold value.

According to the optical device of the eighth aspect, the transmission member can be heated in advance to prevent dew condensation.

In the optical device of the eighth aspect described above, the configuration of measuring the temperature of the light emitting and receiving window based on the resistance value of the heater for heating the light receiving and receiving window may be adopted as the ninth aspect.

According to the optical device of the ninth aspect, the temperature of the light emitting / receiving window can be measured without measuring values other than the current and the voltage.

In the optical device of the eighth aspect described above, a configuration in which the temperature of the light receiving / receiving window is measured based on the elapsed time from the start time of power supply to the distance image sensor may be adopted as the tenth aspect. ..

According to the optical device of the tenth aspect, the temperature of the light emitting / receiving window can be measured without providing anything in the light emitting / receiving window.

The figure which shows the structure of the optical device which concerns on Example Diagram showing an example of distance measurement value and light intensity value The figure which shows an example of the operation procedure in a heat treatment

[1] Example FIG. 1 shows the configuration of the optical device 1 according to the embodiment. The optical device 1 is a device that irradiates light and measures the distance to the object based on the light reflected by the object and returned. The optical device 1 includes a laser flooding unit 11, a laser light receiving unit 12, a half mirror 13, a movable mirror 14, a light emitting / receiving window 15, a heater 16, a ranging unit 21, a control unit 22, and a power supply. A unit 23, a temperature / humidity sensor 24, and a heater driver 25 are provided.

The laser projection unit 11 is a light source that emits a predetermined amount of light. In this embodiment, the laser light emitting unit 11 is an LED rod in which LEDs (Light Emitting Diodes) are arranged in a row in the main scanning direction A11. In FIG. 1, the main scanning direction A11 is a direction along the depth direction of the figure. The laser light receiving unit 12 is an image sensor in which a plurality of light receiving elements that receive the reflected light of the light emitted by the laser light projecting unit 11 and convert it into an electric signal are arranged in a row. The laser light receiving unit 12 has the same number of light receiving elements as the LEDs of the laser light projecting unit 11.

The electric signal converted from the light received by the laser light receiving unit 12 represents an image of an object that reflects the light, as will be described later. The half mirror 13 transmits light incident on one surface (transmissive surface) and totally reflects light incident on the opposite surface (reflection surface). The half mirror 13 is provided at a position where the light emitted by the laser projection unit 11 is incident on the transmission surface and the incident light of the light is totally reflected toward the laser light receiving unit 12.

The movable mirror 14 is a mirror provided so as to be movable in the sub-scanning direction A12. The sub-scanning direction A12 is a direction orthogonal to the main scanning direction A11, and is a rectangular image due to scanning in the main scanning direction A11 and then scanning by one row in the sub-scanning direction A12. Is formed. The movable mirror 14 reflects the light of the laser projecting unit 11 that has passed through the half mirror 13 toward the light emitting / receiving window 15 while moving in the sub-scanning direction A12.

In this embodiment, as described above, the movable mirror 14 moves along the uniaxial path along the sub-scanning direction A12. For example, the laser projection unit 11 has only one LRD and the main scanning direction. Scanning in two directions may be performed by moving a biaxial path along A11 and the sub-scanning direction A12. The light emitting / receiving window 15 is a transparent window provided at the boundary between the internal space B1 and the external space B2 of the own device and transmitting the light projected by the laser light emitting unit 11 and the light received by the laser light receiving unit 12. be.

When the temperature difference between the internal space B1 and the external space B2 becomes large, the air near the inner surface 151 on the internal space B1 side of the light receiving / receiving window 15 cooled by the air in the external space B2 is cooled, and water droplets adhere to the inner surface 151. A phenomenon, so-called dew condensation, may occur. When dew condensation occurs, the reflected light incident on the light emitting / receiving window 15 hits water droplets and diffuses when emitted from the inner surface 151, and the amount of light received by the laser light receiving unit 12 decreases. As a result, an accurate image of the light-reflecting object is not represented.

The heater 16 is a heating device provided for preventing dew condensation that causes deterioration of image quality as described above. The heater 16 has a heating wire that generates heat by passing electricity, and the heating wire is attached to the inner surface 151 of the light emitting / receiving window 15. By passing electricity through the heating wire, the heater 16 heats the inner surface 151 side of the light emitting / receiving window 15. When the inner surface 151 side of the light emitting / receiving window 15 is heated by the heater 16, the air near the inner surface 151 is not cooled, and dew condensation can be prevented.

In FIG. 1, an optical path A1 from the laser projection unit 11 to the half mirror 13, an optical path A2 in which light reciprocates from the half mirror 13 via a movable mirror 14 and a light emitting / receiving window 15, and a laser receiving unit from the half mirror 13. The optical path A3 up to 12 is represented. In the optical path A2 ahead of the half mirror 13, the optical path of the irradiation light and the reflected light is common, and the optical device 1 is irradiated with light from the same direction as the reflected light is incident on the light emitting / receiving window 15. It is a so-called coaxial optical system.

The ranging unit 21 measures the distance to an object that reflects the light received by the laser light receiving unit 12 and the amount of the reflected light. The ranging unit 21 is notified of each LED that the laser light projecting unit 11 has started irradiating light, and is notified of each light receiving element that the reflected light has been received from the laser light receiving unit 12. The distance measuring unit 21 measures each pixel with half the distance traveled by the light from the start time of irradiation to the time when the reflected light is received as the distance to the object.

In this way, the distance measuring unit 21 functions as a distance image sensor of a coaxial optical system called an optical device 1. Further, an electric signal indicating the waveform of the reflected light received from the laser light receiving unit 12 is supplied to the distance measuring unit 21 for each light receiving element. The ranging unit 21 measures the amount of received reflected light for each pixel based on the supplied waveform. The distance measuring unit 21 repeatedly measures the distance and the amount of light for each pixel at predetermined time intervals. The ranging unit 21 supplies the measured distance measuring value (hereinafter referred to as “distance measuring value”) and the light quantity value (hereinafter referred to as “light quantity value”) to the control unit 22.

The control unit 22 controls each unit included in the own device. The control unit 22 includes a processor, a memory, and a storage. The processor has, for example, an arithmetic unit such as a CPU (Central Processing Unit), registers, peripheral circuits, and the like. The memory is a recording medium that can be read by a processor, and includes a RAM (Random Access Memory), a ROM (Read Only Memory), and the like. The storage is a recording medium readable by the processor and includes, for example, a hard disk drive or flash memory.

The processor controls the operation of each part of its own device by executing a program stored in ROM or storage using RAM as a work area. The control unit 22 instructs the laser projection unit 11 to start emitting light. Further, the control unit 22 controls the movement of the movable mirror 14 in the sub-scanning direction. The movable mirror 14 supplies a signal indicating the current position in the sub-scanning direction to the control unit 22.

The control unit 22 is supplied with a distance value and a light quantity value from the distance measuring unit 21 to the object measured for each pixel. The control unit 22 generates a distance image representing the distance to the object for each pixel based on the signal indicating the position of the supplied movable mirror 14, the distance measurement value for each pixel, and the light amount value. The control unit 22 generates one distance image each time the distance measurement value and the light intensity value are measured. One distance image generated in this way is also called a "frame". The control unit 22 transmits image data indicating the generated distance image (frame) to, for example, an external device including a display.

The power supply unit 23 is connected to an external power source and supplies electric power to each unit included in the own device. The temperature / humidity sensor 24 is provided inside the own device and measures the temperature and humidity of the air in the internal space B1 and the temperature of the inner surface 151 of the light receiving / receiving window 15. The temperature / humidity sensor 24 measures, for example, the temperature of the light-receiving window 15 based on the resistance value of the heating wire of the heater 16 that heats the light-receiving window 15. The heating wire is, for example, an alloy such as iron, chromium, aluminum, or nickel, and its resistance value changes depending on the temperature.

The temperature / humidity sensor 24 calculates the temperature of the heating wire from the current resistance value of the heating wire by storing the relationship between the temperature of the heating wire and the resistance value in advance. When the temperature of the heating wire rises, the temperature of the light emitting / receiving window 15 also rises with a slight delay, and finally becomes equal to the temperature of the heating wire. Therefore, the temperature / humidity sensor 24 measures the calculated temperature of the heating wire as the temperature of the inner surface 151 of the light receiving / receiving window 15.

The resistance value of the heating wire can be calculated if the current and voltage flowing through the heating wire are known. As described above, in this embodiment, the temperature of the inner surface 151 of the light emitting / receiving window 15 can be measured without measuring values other than the current and the voltage. The temperature / humidity sensor 24 supplies the measured values of air temperature and humidity and the measured values of the temperature of the inner surface 151 to the control unit 22.

The heater driver 25 is controlled by the control unit 22 to drive the heater 16 to heat the inner surface 151 side of the light emitting / receiving window 15. The control unit 22 determines whether or not there is condensation on the light emitting / receiving window 15 based on the distance (distance measuring value) and the amount of light (light quantity value) from the distance measuring unit 21 to the supplied object. Specifically, when the distance measurement value within a predetermined range is measured and the light intensity value of the pixel to which the distance measurement value is measured is within the predetermined range, the control unit 22 causes dew condensation on the light emitting / receiving window 15. It is determined that there is.

FIG. 2 shows an example of a distance measurement value and a light intensity value. In FIG. 2, the distance measurement value (mm: millimeter unit) and the light amount value (digit unit) for each frame of a certain pixel in a certain distance image are shown. In the example of FIG. 2, the ranging value is within the range of approximately 100 mm to 800 mm. It should be noted that the reason why the distance measurement value has such a range is that in the optical device 1, the shorter the distance to the object, the shorter the time from the projection to the light reception, and the slight error in the measurement time increases the distance measurement value. This is because it will fluctuate. Further, the light intensity value is within a range of approximately 0 digit to 70 digit. The control unit 22 determines dew condensation, for example, with these ranges as predetermined ranges.

When the control unit 22 determines that there is dew condensation, the control unit 22 controls the heater driver 25 to drive the heater 16 to heat the inner surface 151 side of the light emitting / receiving window 15. As a result, the temperature of the air near the inner surface 151 also rises, and the water droplets become water vapor again and are contained in the air, and dew condensation is reduced. The control unit 22 controls the heater driver 25 so that the heater 16 continues to heat until it is determined that there is no dew condensation.

Further, even if it is determined that there is no dew condensation, the control unit 22 controls the heating by the heater 16 when the possibility of dew condensation is high. Specifically, the control unit 22 causes dew condensation on the light emitting / receiving window 15 based on the measured values of the temperature and humidity of the air in the own machine (optical device 1) and the measured values of the temperature of the light emitting / receiving window 15. An index of ease (hereinafter referred to as "condensation index") is calculated. For example, the control unit 22 first calculates the absolute humidity C1 from the measured values of the temperature and humidity of the air.

Further, as described above, the temperature / humidity sensor 24 supplies the control unit 22 with the measured value T1 of the temperature of the inner surface 151 of the light emitting / receiving window 15. Since the temperature of the air in the vicinity of the inner surface 151 is close to the temperature of the inner surface 151, that is, the supplied measured value T1, the control unit 22 calculates the saturated water vapor amount D1 in the air having the measured value T1. The control unit 22 determines whether or not the absolute humidity C1 + α> the saturated water vapor amount D1 is based on the absolute humidity C1 and the saturated water vapor amount D1 calculated as described above.

It should be noted that α is a margin, and is determined according to, for example, the characteristics of the optical device 1. Absolute humidity C1 + α is an example of the "index" of the present invention. When the absolute humidity C1 + α> the saturated water vapor amount D1, the control unit 22 determines that dew condensation is likely to occur, and heats the light emitting / receiving window 15. As described above, the control unit 22 heats the light emitting / receiving window 15 when the calculated dew condensation index (absolute humidity C1 + α) is equal to or higher than a predetermined threshold value (saturated water vapor amount D1). As a result, it is possible to prevent dew condensation by heating the light emitting / receiving window 15 in advance in a situation where dew condensation is likely to occur.

The distance measuring unit 21 and the control unit 22 determine the dew condensation based on the above configuration, and if necessary, heat the light emitting / receiving window 15 to perform a heat treatment to prevent dew condensation.
FIG. 3 shows an example of an operation procedure in heat treatment. First, the control unit 22 starts light emission by the laser projection unit 11 which is a light source (step S11). Next, the control unit 22 measures the temperature and humidity of the air in the internal space B1 of the own machine and the temperature of the inner surface 151 of the light receiving / receiving window 15 (step S12).

Subsequently, the ranging unit 21 measures the ranging value and the light intensity value (step S13). Next, the control unit 22 determines whether or not there is condensation on the light emitting / receiving window 15 based on the distance measurement value and the light amount value (step S14). When it is determined in step S14 that there is no dew condensation (NO), the control unit 22 calculates and calculates a dew condensation index based on the measured values of the temperature and humidity of the air in the own machine and the measured values of the temperature of the light emitting / receiving window 15. It is determined whether or not the dew condensation index is equal to or higher than the threshold value (step S15).

When it is determined in step S14 that there is dew condensation (YES), and when it is determined in step S15 that the dew condensation index is equal to or greater than the threshold value (YES), the control unit 22 controls the heater driver 25 to control the light emitting / receiving window 15. Is heated (step S16). After step S16, the control unit 22 returns to step S12 to perform an operation. When it is determined in step S15 that the dew condensation index is not equal to or greater than the threshold value (NO), the control unit 22 determines whether or not the light emitting / receiving window 15 is being heated (step S17).

If it is determined in step S17 that heating is not in progress (NO), the control unit 22 returns to step S12 and operates. If it is determined in step S17 that heating is in progress (YES), the control unit 22 stops heating the light emitting / receiving window 15 (step S18). After step S18, the control unit 22 returns to step S12 to perform an operation.

In this embodiment, as described above, the determination of dew condensation was performed using both the distance measurement value and the light intensity value. Thereby, for example, the accuracy of the determination of dew condensation can be improved as compared with the case where the determination of dew condensation is performed using only the distance measurement value. Further, in the present embodiment, since the determination of dew condensation is performed based on the light emitted by the optical device 1 itself, it is possible to determine the dew condensation regardless of the brightness of the surroundings (especially even when the surroundings are dark).

[2] Modifications The above-mentioned examples are merely examples of the implementation of the present invention, and may be modified as follows. Moreover, you may combine Examples and each modification as needed.

[2-1] Dew condensation determination method The control unit 22 has dew condensation on the light emitting / receiving window 15 when the distance measurement value within a predetermined range is measured by using only the distance measurement value without using the light amount value. May be determined. The distance measurement value may be close to that of a nearby object and water droplets of dew condensation, but even in that case, even in such an environment where the light emitting / receiving window 15 is not contaminated and only a distant object is measured. For example, the presence or absence of dew condensation can be determined based only on the distance measurement value of each pixel included in the distance image.

Further, on the contrary, even if the control unit 22 determines that there is dew condensation on the light emitting / receiving window 15 when the light quantity value within a predetermined range is measured by using only the light quantity value without using the distance measurement value. good. The light intensity value may be close to that of a distant object and water droplets of dew condensation, but even in that case, the light intensity value of each pixel included in the distance image is used in an environment where only a nearby object is measured. The presence or absence of dew condensation can be determined based solely on. Further, in either case, it is possible to reduce the processing load when determining the presence or absence of dew condensation, as compared with the case where both the distance measurement value and the light amount value are used.

[2-2] Measurement error In the measurement of the measured value and the light intensity value, an error may occur in the measured value and the light intensity value on a pixel-by-pixel basis due to the influence of disturbance or the like. When this error occurs, it may be erroneously determined that there is condensation even though there is no condensation. In this modification, the determination of dew condensation is performed to avoid such an erroneous determination.

The control unit 22 of this modification is thrown when the distance measurement value within a predetermined range is measured and the pixels for which the light intensity value within the predetermined range is measured are adjacent or close to each other by a predetermined number or more within a predetermined distance. It is determined that there is dew condensation on the light receiving window 15. When the pixels are arranged in a grid pattern, the adjacent pixels are pixels that are in contact with the top, bottom, left, and right of a certain pixel, or pixels that are located diagonally above or diagonally below a certain pixel. Further, the adjacent pixels are, for example, pixels separated from a certain pixel within a predetermined distance.

The predetermined distance and the predetermined number are determined based on the size of the minimum water droplet that can adhere to the light receiving / receiving window 15 in the distance image. For example, when the smallest water droplet has a size of 3 × 3 pixels, the length of 3 pixels is defined as a predetermined distance, and 9 pixels are defined as a predetermined number. In addition, this modification may be applied even when the determination of dew condensation is performed using only the distance measurement value. In that case, the control unit 22 determines that there is dew condensation on the light emitting / receiving window 15 when the pixels whose distance measurement values within the predetermined range are measured are adjacent to or close to a predetermined number within a predetermined distance.

Further, this modification may be applied to the case where the determination of dew condensation is performed using only the light amount value. In that case, the control unit 22 determines that there is dew condensation on the light emitting / receiving window 15 when the pixels whose light amount values within the predetermined range are measured are adjacent to or close to a predetermined number within a predetermined distance. In either case, the erroneous determination when an error occurs in the distance measurement value or the light intensity value due to the influence of disturbance or the like can be suppressed as compared with the case where the size of the water droplet is not taken into consideration.

[2-3] Areas that are prone to dew condensation In the light receiving / receiving window 15, a region that is prone to dew condensation may be determined. For example, when there is a member that generates heat in the own machine, the area farther from the member is more likely to be cooled by the outside air and dew condensation is more likely to occur. Therefore, in this modification, the control unit 22 determines the presence or absence of dew condensation on the light emitting / receiving window 15 based on the measured values of the pixels in the predetermined region of the distance measuring unit 21.

As the predetermined region, a region where dew condensation is likely to occur in the light emitting / receiving window 15 is defined. A plurality of predetermined regions may be defined, or any size region may be defined as long as it is smaller than the entire light emitting / receiving window 15. According to this modification, since the pixels other than the predetermined region are not used for the determination processing, the load of the determination processing can be reduced as compared with the case where the measured values for the entire pixels of the distance image are used. can.

[2-4] Method for measuring the temperature of the light emitting / receiving window In the embodiment, the temperature / humidity sensor 24 measures the temperature of the light emitting / receiving window 15 based on the resistance value of the heating wire of the heater 16, but the light receiving / receiving window 15 is measured. The method for measuring temperature is not limited to this. In this modification, for example, the control unit 22 measures the temperature of the light emitting / receiving window 15 based on the elapsed time from the start time of power supply to the distance measuring unit 21.

In this modification, the power supply unit 23 first supplies power to the control unit 22, and then supplies power to other units. Further, when the power supply unit 23 starts supplying power to the distance measuring unit 21, the power supply unit 23 notifies the control unit 22 to that effect. The control unit 22 stores the time when this notification is received as the start time of power supply to the distance measuring unit 21. When the distance measuring unit 21 operates, the laser light emitting unit 11 and the laser light receiving unit 12 also operate for measurement, and generate heat, respectively.

The heat generated in this way propagates through the housing of the own machine and air to warm the light emitting / receiving window 15. The control unit 22 stores in advance the correlation between the elapsed time from the start time of power supply to the distance measuring unit 21 and the temperature of the light emitting / receiving window 15. The control unit 22 specifies a temperature that correlates with the elapsed time from the time when the above notification is received as the current temperature of the light receiving / receiving window 15. According to this modification, the temperature of the light-receiving window 15 can be measured without providing anything to the light-receiving window 15 or the heater 16.

[2-5] Category of Invention The present invention can be regarded as an information processing method for realizing the processing performed by the distance measuring unit 21 and the control unit 22 of the optical device 1 in addition to the optical device 1, and is also regarded as an optical device. It can also be regarded as a program for operating the computer that controls 1. This program may be provided in the form of a recording medium such as an optical disk that stores it, or may be provided in the form of being downloaded to a computer via a network such as the Internet and installed and made available. May be done.

1 ... Optical equipment, 11 ... Laser light projecting unit, 12 ... Laser light receiving unit 13 ... Half mirror, 14 ... Movable mirror, 15 ... Projecting light receiving window, 16 ... Heater, 21 ... Distance measuring unit, 22 ... Control unit, 23 ... Power supply unit, 24 ... Humidity sensor, 25 ... Heater driver.

In order to solve the above-mentioned problems, in the present invention, the distance measurement value within a predetermined range is measured by the distance image sensor of the coaxial optical system, the measured value of the air temperature and humidity in the own machine, and the distance image. When the elapsed time from the start time of power supply to the sensor and the index of the susceptibility to dew condensation in the light emitting / receiving window of the distance image sensor calculated based on the predetermined threshold value or more, the light receiving / receiving window is fitted with the light emitting / receiving window . As the first aspect, an optical device that determines that there is dew condensation and heats the light emitting / receiving window is provided.

According to the optical device of the first aspect, it is possible to determine dew condensation regardless of the ambient brightness. Further, according to the optical device of the first aspect, the temperature of the light emitting / receiving window can be measured without providing anything in the light emitting / receiving window.

In the optical device of the first aspect described above, when the pixels whose distance measurement values within a predetermined range are measured are adjacent or close to each other by a predetermined number or more within a predetermined distance, it is determined that there is dew condensation on the light emitting / receiving window. , May be adopted as the second aspect.

According to the optical device of the second aspect, it is possible to suppress erroneous determination when an error occurs in the distance measurement value due to the influence of disturbance or the like.

In the optical device of the second aspect described above, when the distance measurement value within a predetermined range is measured and the light intensity value of the pixel to which the distance measurement value is measured is within the predetermined range, dew condensation occurs on the light emitting / receiving window. A configuration in which it is determined that there is a presence may be adopted as the third aspect.

According to the optical device of the third aspect, the accuracy of the determination of dew condensation can be improved as compared with the case where the determination is performed using only the distance measurement value.

In the optical device of the third aspect described above, when the distance measurement value within a predetermined range is measured and the pixels for which the light intensity value within the predetermined range is measured are adjacent or close to each other by a predetermined number or more within a predetermined distance. A configuration in which it is determined that there is dew condensation on the light receiving / receiving window may be adopted as the fourth aspect.

According to the optical device of the fourth aspect, it is possible to suppress erroneous determination when an error occurs in the distance measurement value or the light intensity value on a pixel- by -pixel basis due to the influence of disturbance or the like.

In the optical instrument according to any one of the first to fourth aspects , the distance measurement value within a predetermined range is measured, and the distance measurement value is a distance measurement value for a pixel in a predetermined area of the distance image sensor. A configuration in which it is determined that there is dew condensation on the light receiving / receiving window in a certain case may be adopted as the fifth aspect.

According to the optical device of the fifth aspect, the load of the determination process can be reduced.

In order to solve the above-mentioned problems, the present invention measures and measures the temperature of the light emitting / receiving window of the distance image sensor based on the elapsed time from the start time of power supply to the distance image sensor of the coaxial optical system. Based on the temperature of the light-receiving window and the measured values of the temperature and humidity of the air inside the machine, an index of the susceptibility to dew condensation in the light-receiving window is calculated, and a predetermined range is determined by the distance image sensor. The first aspect is an optical device that determines that there is dew condensation on the light emitting / receiving window and heats the light receiving / receiving window when the distance measurement value in the inside is measured and the index is equal to or higher than a predetermined threshold value. offer.

Claims (10)

An optical device that heats the light emitting / receiving window when it is determined that there is dew condensation on the light emitting / receiving window of the distance image sensor based on the distance measurement value of the distance image sensor of the coaxial optical system. The optical device according to claim 1, wherein it is determined that there is dew condensation on the light emitting / receiving window when a distance measurement value within a predetermined range is measured. The optical device according to claim 1, wherein when the pixels whose distance measurement values within a predetermined range are measured are adjacent or close to each other by a predetermined number or more within a predetermined distance, it is determined that there is dew condensation on the light emitting / receiving window. The optical device according to any one of claims 1 to 3, wherein the presence or absence of dew condensation in the light emitting / receiving window is determined based on the light intensity value measured by the distance image sensor in addition to the distance measuring value. The fourth aspect of claim 4, wherein it is determined that there is dew condensation on the light emitting / receiving window when the distance measurement value within a predetermined range is measured and the light intensity value of the pixel to which the distance measurement value is measured is within the predetermined range. Optical equipment. It is determined that there is dew condensation on the light emitting / receiving window when the distance measurement value within a predetermined range is measured and the number of pixels whose light intensity value within the predetermined range is measured is more than a predetermined number within a predetermined distance, adjacent to or close to each other. The optical device according to claim 4. The optical device according to any one of claims 1 to 6, wherein the presence or absence of dew condensation in the light emitting / receiving window is determined based on a measured value of a pixel in a predetermined area of the distance image sensor. When the index of the susceptibility to dew condensation in the light receiving / receiving window calculated based on the measured values of the temperature and humidity of the air in the own machine and the measured value of the temperature of the light receiving / receiving window is equal to or higher than a predetermined threshold value. The optical device according to any one of claims 1 to 7, which heats a light receiving / receiving window. The optical device according to claim 8, wherein the temperature of the light emitting / receiving window is measured based on the resistance value of the heater that heats the light receiving / receiving window. The optical device according to claim 8, wherein the temperature of the light emitting / receiving window is measured based on the elapsed time from the start time of power supply to the distance image sensor.

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