JP2016035398A - Distance measurement apparatus and distance measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a distance measurement apparatus and a distance measuring method capable of precisely measuring the distance while preventing influences by disturbance light.SOLUTION: The distance measurement apparatus includes: a light source 111 that emits an illumination light of 1290nm or larger and 1330nm or smaller in wavelength toward an object; and a detector 112 that detects a reflection light of the illumination light reflected by the object. The distance up to the object is measured based on the phase difference between the illumination light emitted from the light source and the reflection light detected by the detector.SELECTED DRAWING: Figure 1

Description

  The present application relates to a distance measuring device.

  The technology for detecting pedestrians and obstacles and measuring the distance to them is an important technology that contributes to improving the safety of automobiles and the like.

  One technique for measuring the distance to an object (hereinafter referred to as a distance measurement technique) is a TOF distance measurement technique. This technique measures the distance to an object by measuring the time (flight time) required for the illumination light emitted from the light source to be reflected by the object and the reflected light to reach the detector. In order to measure the time of flight (TOF), intensity modulation is applied to the illumination light. The detector has a function of detecting the difference between the intensity phase of the irradiation light and the intensity phase of the reflected light. Since this intensity phase difference corresponds to the time of flight, distance measurement can be performed.

  The TOF distance measurement technology uses beam-shaped illumination light, a technique called a rider that performs distance measurement in only one direction at a time, and distance measurement in multiple directions at once using spatially wide illumination light. And TOF image sensing technology for photographing an object.

Japanese Patent No. 4105554

  In the TOF distance measurement technique, reflected light from an object by illumination light is detected. For this reason, the detection of reflected light is affected by disturbance light such as light sources other than illumination light and sunlight.

  One non-limiting exemplary embodiment of the present application provides a distance measuring apparatus and a distance measuring method capable of suppressing the influence of ambient light and performing highly accurate distance measurement.

  A distance measuring device according to one aspect of the present application includes a light source that emits illumination light having a center wavelength of 1290 nm or more and less than 1330 nm toward an object, and a detector that detects reflected light from the object of the illumination light, The distance to the object is measured based on the phase difference between the illumination light emitted from the light source and the reflected light detected by the detector.

  According to the distance measuring device and the distance measuring method disclosed in the present application, it is possible to perform highly accurate distance measurement by suppressing the attenuation of illumination light and suppressing the influence of ambient light such as sunlight. .

FIG. 1 is a schematic diagram showing the configuration of a distance measuring device common to the embodiments of the present application. (A) is a schematic diagram which shows operation | movement in case a ranging device is an image sensor, (b) is a figure which shows the timing of illumination light and reflected light, (c) and (d) are image | photographed. It is a schematic diagram which shows the example of the obtained image. It is a figure which shows the example of the spectrum on the ground of sunlight. In 1st Embodiment, it is a figure which shows an example of the spectrum of the sunlight actually measured. In 1st Embodiment, it is a figure which shows the result which measured the spectrum of the halogen lamp indoors on two conditions from which temperature and humidity differ, and represented the difference of the measurement result in percent. It is a figure which shows collectively the result shown in FIG. 4 and FIG. (A) shows the intensity | strength of the sunlight on the ground in wavelength 1300nm to 1500nm, (b) has shown the absorption coefficient of water in the same wavelength range.

  When the disturbance light in the TOF distance measurement technique is strong, the intensity of the illumination light necessary for detecting the phase difference is relatively weak, and the accuracy of detecting the illumination light is lowered. In general, the intensity of sunlight in the daytime is considerably larger than the illumination light used for TOF distance measurement, and therefore, particularly when the TOF distance measurement technology is used for an automobile or the like, the influence of sunlight becomes significant.

  In order to suppress the influence of sunlight, a method of using a wavelength range where sunlight is specifically weak (a wavelength range lacking sunlight) can be considered. This utilizes the fact that only light in a specific wavelength region is absorbed by water vapor or the like in the atmosphere before sunlight reaches the ground surface. Since light in this wavelength range is weaker than other wavelength ranges, if light in this wavelength range is used as illumination light for TOF distance measurement, it will not be affected by disturbance light even during daylight weather. Can be small.

  However, in the sun light missing wavelength region where sunlight is specifically weak, absorption due to water vapor or the like in the atmosphere occurs, so that the illumination light of the ranging technique is also affected by the absorption. In other words, when light in a wavelength region lacking sunlight is used as illumination light, illumination light emitted from the light source is also greatly attenuated in the atmosphere, and there is a possibility that a sufficient amount of reflected light does not reach the detector.

  This problem can be particularly acute in TOF image sensing technology. In the TOF image sensing technology, it is necessary to use illumination light having a spatial spread. Therefore, even when there is no absorption due to water vapor or the like, the reflected light from a distant object is weak. This is because if absorption by water vapor or the like is added thereto, there is a high possibility that a sufficient amount of reflected light will not reach the detector. Each pixel of the image sensor used for the TOF image sensing technology is smaller than the detector used for the rider. Therefore, the sensitivity of each pixel of the image sensor is lower than the sensitivity of the detector used for the rider. From this point of view, attenuation of illumination light is an important issue in the TOF image sensing technology.

  In view of such a problem, the inventor of the present application has come up with a novel distance measuring device and distance measuring method using illumination light having a wavelength capable of suppressing the influence of external light. The outline of the distance measuring apparatus and distance measuring method of the present application is as follows.

  A distance measuring device according to one aspect of the present application includes a light source that emits illumination light having a center wavelength of 1290 nm or more and less than 1330 nm toward an object, and a detector that detects reflected light from the object of the illumination light, The distance to the object is measured based on the phase difference between the illumination light emitted from the light source and the reflected light detected by the detector. In this wavelength region, since strong attenuation due to water vapor does not occur, it is possible to suppress propagation attenuation of illumination light while suppressing disturbance factors. Therefore, it is possible to realize long distance ranging with particularly high accuracy.

  A distance measuring apparatus according to another aspect of the present application includes a light source that emits illumination light having a central wavelength of 1440 nm to 1530 nm toward an object, and a detector that detects reflected light of the illumination light from the object. The distance to the object is measured based on the phase difference between the illumination light emitted from the light source and the reflected light detected by the detector. In this wavelength region, since strong attenuation due to water vapor does not occur, it is possible to suppress propagation attenuation of illumination light while suppressing disturbance factors. Therefore, it is possible to realize long distance ranging with particularly high accuracy.

  The center wavelength of the illumination light may be in a range of 1440 nm or more and less than 1490 nm. In this wavelength region, sunlight is more strongly attenuated. For this reason, disturbance due to sunlight can be further suppressed, and further accurate distance measurement can be realized.

  A distance measuring apparatus according to another aspect of the present application includes a light source that emits illumination light having a central wavelength of 1350 nm or more and less than 1380 nm toward an object, and a detector that detects reflected light of the illumination light from the object. The distance to the object is measured based on the phase difference between the illumination light emitted from the light source and the reflected light detected by the detector. By using illumination light in this wavelength region, it is possible to realize a distance measuring device capable of measuring distance with high accuracy by suppressing attenuation of illumination light even in the case of rain or fog.

  The light source emits the intensity-modulated illumination light, and the detector is an image sensor in which a plurality of pixels are arranged two-dimensionally, and generates a range image based on the phase difference. Also good. Even when an image sensor with small pixels is used, the S / N ratio can be increased and the intensity of illumination light to be detected can be increased, and a highly accurate range image can be obtained using the image sensor. Become. Therefore, a TOF image sensor can be preferably realized.

A distance measuring method according to one aspect of the present application emits illumination light having a center wavelength of 1290 nm or more and less than 1330 nm toward an object, and detects reflected light of the illumination light from the object with a detector.
A distance to the object is measured based on a phase difference between illumination light emitted from the light source and reflected light detected by the detector.

  A distance measuring method according to another aspect of the present application emits illumination light having a central wavelength of 1440 nm or more and 1530 nm or less toward an object, detects reflected light of the illumination light from the object with a detector, and emits light from the light source. The distance to the object is measured based on the phase difference between the emitted illumination light and the reflected light detected by the detector.

  The center wavelength of the illumination light may be in a range of 1440 nm or more and less than 1490 nm.

  A distance measuring method according to another aspect of the present application emits illumination light having a central wavelength of 1350 nm or more and less than 1380 nm toward an object, detects reflected light of the illumination light from the object with a detector, and emits light from the light source. The distance to the object is measured based on the phase difference between the emitted illumination light and the reflected light detected by the detector.

  The illumination light is intensity-modulated, and the detector may be an imaging device in which a plurality of pixels are two-dimensionally arranged, and may generate a distance image based on the phase difference.

(Outline of distance measuring device and distance measuring method)
First, a distance measuring apparatus and a distance measuring method common to the embodiments of the present application will be described. FIG. 1 schematically shows an outline of the configuration of a distance measuring apparatus common to the following embodiments. The distance measuring device 101 includes a light source 111, a detector 112, a control device 113, and a signal processor 114. The distance measuring device 101 may be a rider (LIDAR, Light Detection and Ranging) or an image sensor. Moreover, in this-application specification, visible light and infrared rays are called "light."

  Part or all of the signal processor 114 may be configured by hardware or may be configured by software. The control device 113 and the signal processor 114 may be configured by a microcomputer 115 including a signal processing device, a memory, and an input / output unit. In addition, the control device 113 or the signal processor 114 may be integrated on the same semiconductor element as the detector 112.

  First, the configuration and operation when the distance measuring device 101 is a rider will be described. The light source 111 emits illumination light having a predetermined wavelength. Illumination light is, for example, laser light and is a pulse wave. The detector 112 is configured by, for example, a photodiode or a phototransistor. The detector 112 detects reflected light generated by being emitted from the light source 111 and reflected by an object. A band-pass filter that selectively transmits light in a band including the wavelength of reflected light may be provided on the light receiving surface of the detector 112 so as not to detect disturbance light other than illumination light.

  The signal processor 114 calculates and outputs the phase difference (time difference) between the illumination light emitted from the light source 111 and the reflected light detected by the detector 112. The control device 113 controls timing for emitting illumination light from the light source 111, timing for detecting reflected light by the detector 112, timing for detecting phase difference by the signal processor 114, and the like.

  When the phase difference is Δt, the distance from the object to the distance measuring device 101 is L, and the speed of light is c, Δt = 2L / c. Therefore, the distance L can be obtained by L = Δt · c / 2.

  When the distance measuring device 101 is a TOF image sensor, the light source 111 emits intensity-modulated illumination light whose intensity periodically changes. For example, the illumination light may be a pulse wave having a predetermined period, or may be a continuous wave whose intensity changes periodically, such as a sine wave. The detector 112 is an image sensor in which a plurality of pixels are arranged two-dimensionally.

 The operation when the distance measuring device 101 is a TOF image sensor will be described with reference to FIGS. FIG. 2A schematically shows illumination light 152 and reflected light 153A, 153B when the distance measuring device 101 measures the distance to the objects 151A, 151B. FIG. 2B is a timing chart of the illumination light 152 and the reflected lights 153A and 153B. When the illumination light 152 is transmitted from the light source 111 of the distance measuring apparatus 101, the illumination light 152 first reaches the object 151A close to the distance measuring apparatus 101, and the reflected light 153A is generated. Thereafter, the illumination light 152 reaches a distant object 151B, and reflected light 153B is generated. As shown in FIG. 2B, the reflected light 153A reaches the detector 112 with a phase difference of Δt1 with respect to the illumination light 152, and the reflected light 153B reaches the detector 112 with a phase difference of Δt2.

  The detector 112 detects the reflected light 153A and the reflected light 153B for each pixel. If different frame images are generated with a phase difference of Δt1 and a phase difference of Δt2 with respect to the illumination light 152, as shown in FIGS. 2C and 2D, a frame in which only the object 151A is captured, and the object 151B Only the frame where only the image was taken is obtained. The image included in the frame shown in FIG. 2C is at a distance indicated by L = Δt1 · c / 2, and the image included in the frame shown in FIG. 2D is L = Δt2 · c / 2. At the indicated distance. In this way, the distance measuring apparatus 101 can obtain a distance image for each pixel. Further, if all frames acquired within the pulse period of the illumination light 151A, such as the frame shown in FIG. 2C and the frame shown in FIG. 2D, are combined, they are within the distance measurement range of the distance measuring device 101. Images corresponding to one frame of a normal captured image can be obtained by superimposing frames. Therefore, the distance measuring apparatus 101 can perform distance measurement and acquisition of images (still images and moving images).

  In the following, as will be described in detail, the distance measuring apparatus 101 of each embodiment of the present application uses light having a wavelength in the near infrared region as illumination light. As a light source for emitting light having a wavelength in this region, a compound semiconductor laser composed of InAs, InSb, InP, GaAs and mixed crystals thereof, LED, Si Raman laser, a fiber laser using an optical fiber doped with a rare earth, a visible light laser For example, a light source converted into the near infrared using a nonlinear optical element can be used.

  As the detector, a photodiode or phototransistor made of InAs, InSb, Si, Ge, InP, GaAs, or a mixed crystal thereof can be used. The time accuracy required for ranging with a resolution of 1 m (measurement accuracy) is 3.3 nanoseconds. For this reason, the detector for realizing this measurement accuracy has a structure capable of operating at a speed of 330 MHz or higher. For example, a detector provided with an image sensor made of an InGaAs photodiode can be used. In addition, since the required measurement accuracy changes with uses, what is necessary is just to use the detector which operate | moves at the speed | rate which can satisfy a required measurement accuracy.

  For the entire distance measuring device 101 excluding the wavelength of illumination light, for example, the device disclosed in Japanese Patent Laid-Open No. 2000-121339 or the device disclosed in Japanese Patent Laid-Open No. 2006-844429 may be used. Moreover, you may use the imaging device using the distance image sensor by which the pixel value became a distance value disclosed by Unexamined-Japanese-Patent No. 2006-84429.

  One of the features of the distance measuring apparatus of each embodiment disclosed in the present application is that, as described above, illumination light having a wavelength capable of suppressing the influence of external light is used. Hereinafter, each embodiment will be described in detail.

(First embodiment)
FIG. 3 shows the spectrum of sunlight passing through the atmosphere published by the US National Renewable Energy Laboratory (NREL). Sunlight includes visible light and infrared light, and as described above, the intensity is largely reduced in a specific wavelength band (indicated by an arrow in the figure) due to absorption mainly by water vapor in the atmosphere. The inventor of the present application actually measured the intensity of sunlight in the wavelength band of sunlight from 1,200 nm to 1,600 nm, and examined the decrease in intensity in detail.

  FIG. 4 shows the measurement result of sunlight intensity. This spectrum was measured in Osaka during a clear day in summer. For the measurement, a near infrared spectrometer NIRQuest 512 manufactured by Ocean Optics was used. An optical fiber having a core diameter of 200 μm was connected to this spectroscope, and measurement was performed by introducing direct sunlight into the fiber end face.

  This spectrometer has different quantum efficiencies for each wavelength. For this reason, the sunlight intensity for every wavelength cannot be simply compared. However, since the quantum efficiency changes gently with respect to the wavelength, it can be concluded that the incident light quantity of sunlight is changing in the section where the slope changes rapidly.

  From FIG. 4, it is recognized that sunlight is attenuated in the wavelength band of 1290 nm to 1530 nm. In addition, the change in sunlight intensity is small in the range from the wavelength 1350 nm to the wavelength 1490 nm within this range. The reason why the intensity does not change greatly in this range is considered to be that the intensity of sunlight is weak and it is below the measurement limit that can be achieved by the dark current, stray light, amplifier, etc. of the spectrometer. That is, it is recognized that sunlight is strongly attenuated in a wavelength band of 1350 nm to 1490 nm.

  Next, in the laboratory, in order to evaluate the attenuation of light due to water vapor, the spectrum of the halogen lamp was measured under two conditions with different temperatures and humidity. The halogen lamp was used by detaching the object for microscope illumination from the microscope, condensing the light from the halogen lamp with a reflecting telescope from a position 5 m away, introducing it into an optical fiber, and performing spectroscopy. The spectroscope and the optical fiber used for the measurement are the same as those used for the sunlight intensity measurement.

  The measurement was performed under conditions 1 and 2. Condition 1 is room temperature 29.8 ° C. and humidity 68%, and condition 2 is room temperature 24.2 ° C. and humidity 43%. FIG. 5 shows a value obtained by subtracting the measurement result under condition 2 from the measurement result under condition 1 in percent.

  Due to the influence of dark current, lamp luminance change, etc., there is a difference of about 10% regardless of the room temperature or humidity difference in the entire wavelength range. However, another intensity change is clearly observed in the wavelength band of 1330 nm to 1440 nm. This is caused by the difference in the amount of water vapor in the room.

  It cannot be determined that the influence of water vapor at wavelengths outside this range is zero. However, in consideration of measurement accuracy, it can be determined that the influence of water vapor at wavelengths outside this range is similar to noise, and is smaller than the influence of water vapor in the wavelength band of 1330 nm to 1440 nm. Therefore, it can be said that strong attenuation of light due to water vapor is observed in the wavelength band of 1330 nm to 1440 nm.

  The ratio of water vapor to atmospheric pressure is 2.8% in condition 1 and 1.3% in condition 2. That is, the intensity change shown in FIG. 5 is an influence of water vapor of 1.5% at the atmospheric pressure ratio. As the temperature increases, the saturated water vapor pressure increases and the proportion of water vapor in the atmospheric pressure increases. At a temperature of 40 ° C. and a humidity of 100%, the proportion of water vapor in the atmospheric pressure reaches 7.3%. When this temperature and humidity are assumed to be Condition 3, the difference in the amount of water vapor between Condition 3 and Condition 1 reaches four times the difference in the amount of water vapor between Condition 2 and Condition 1. For this reason, in the condition 3, it is considered that the attenuation of light becomes larger in the wavelength band of 1330 nm to 1440 nm.

  The intensity of light passing through the absorber follows Lambert-Beer law. For this reason, the light which permeate | transmits the environment containing water vapor | steam attenuate | damps exponentially with respect to distance. In addition, as the saturated vapor pressure increases and the humidity increases due to an increase in temperature, light is strongly attenuated by water vapor.

  However, since the attenuation of light due to water vapor is due to resonance absorption of water molecules, it is considered that the wavelength at which resonance absorption occurs does not change much even at about the temperature in Condition 3. That is, it is considered that the range in which strong attenuation of sunlight by water vapor is recognized hardly changes at the use environment temperature when the distance measuring device of the present embodiment is used in a vehicle.

  In contrast, light having a wavelength outside the range of 1330 nm to 1440 nm is less absorbed by water vapor than light having a wavelength within this range. Therefore, if light with a wavelength outside this range is used as illumination light, it is possible to irradiate farther objects with sufficient intensity, and it is possible to detect reflected light with high intensity. Moreover, it is hard to be influenced by the rise in temperature and humidity.

  Based on the above results, the wavelength range lacking sunlight in the measured spectrum of sunlight overlaps with the wavelength band in which light is strongly absorbed by water vapor in the actual use environment of the distance measuring device, but may not completely match. I understood. FIG. 6 summarizes these results. The wavelength band of 1200 nm to 1600 nm is divided into the following seven areas from the overlapping of the three ranges of the range where sunlight attenuation is recognized, the range where strong attenuation of sunlight is recognized, and the range where strong attenuation due to water vapor is recognized. Can be divided into

(1) Region 1 (1200 nm or more and less than 1290 nm)
In this region, neither sunlight nor strong water vapor is observed. For this reason, the TOF distance measuring device that uses light having a wavelength in this region as illumination light is strongly influenced by sunlight.

(2) Region 2 (1290 nm or more and less than 1330 nm)
In this region, sunlight is attenuated and strong attenuation due to water vapor is not observed. In this region, the amount of disturbance light is reduced as much as sunlight is attenuated. Moreover, since the attenuation by water vapor | steam is not recognized, illumination light is hard to attenuate. Therefore, a reduction in noise caused by disturbance light can be expected as compared with the region 1, and an improvement in accuracy of TOF ranging can be expected. This effect can be expected for both short-range and long-distance measurement.

(3) Region 3 (1330 nm or more and less than 1350 nm)
In this region, although sunlight is attenuated, strong attenuation due to water vapor is also observed. In this range, a reduction in noise due to disturbance photogenicity can be expected, but there is attenuation due to water vapor. For this reason, it is suitable for short-distance TOF ranging, but is not suitable for long-distance TOF ranging.

(4) Region 4 (1350 nm or more and less than 1440 nm)
In this region, strong attenuation of sunlight is observed, but strong attenuation by water vapor is also observed. In this region, a strong reduction in noise caused by ambient light can be expected. Therefore, improvement in TOF ranging accuracy can be expected. However, since there is also attenuation of illumination light due to water vapor, it is not suitable for long-distance ranging, and is suitable for short-range TOF ranging.

(5) Region 5 (1440 nm or more and less than 1490 nm)
In this region, strong attenuation of sunlight is recognized and strong attenuation due to water vapor is not recognized. In this region, a strong reduction in noise caused by disturbance light can be expected, and the attenuation of illumination light is small. Therefore, it is suitable not only for a short distance but also for a long distance TOF distance measurement. That is, this is the most suitable area for TOF distance measurement. This region is also a region called eye-safe that has a low risk of retinal damage. For this reason, it is possible to use a light source with high brightness, which is suitable for TOF distance measurement. In particular, in a TOF image sensor that uses an image sensor as the detector 112, the use of illumination light having a spatial expansion causes attenuation of light intensity due to the expansion, so that attenuation due to water vapor is suppressed and high brightness is achieved. This is extremely effective in the region 5 where the light source of the above can be used.

(6) Region 6 (1490 nm or more and less than 1530 nm)
In this region, as in region 2, the attenuation of sunlight is recognized and no strong attenuation due to water vapor is observed. In this region, the amount of disturbance light is reduced as much as sunlight is attenuated. Moreover, since the attenuation by water vapor | steam is not recognized, illumination light is hard to attenuate. Therefore, a reduction in noise caused by disturbance light can be expected as compared with the region 1, and an improvement in accuracy of TOF ranging can be expected. This effect can be expected for both short-range and long-distance measurement.

(7) Region 7 (1530 nm to 1600 nm)
In this region, as in region 1, neither sunlight attenuation nor strong attenuation due to water vapor is observed. For this reason, the TOF distance measuring device that uses light having a wavelength in this region as illumination light is strongly influenced by sunlight.

  From the above results, in the distance measuring apparatus of the present embodiment, the illumination light preferably has a center wavelength of 1290 nm or more and less than 1330 nm. Since sunlight attenuates significantly in this wavelength band, it is possible to suppress disturbance factors. In addition, strong attenuation due to water vapor does not occur in this wavelength band. Therefore, the propagation attenuation of the illumination light can be suppressed while suppressing disturbance factors, and highly accurate distance measurement can be realized. For this reason, in particular, when the distance measuring device is a TOF image sensor, the propagation attenuation of the illumination light can be suppressed even when the illumination light having a spatial spread is used. Further, even when an image sensor with small pixels is used, the S / N ratio can be increased and the intensity of illumination light to be detected can be increased, and a highly accurate range image can be obtained using the image sensor. It becomes possible. Therefore, a TOF image sensor can be preferably realized.

  Moreover, it is more preferable that the illumination light has a center wavelength of 1440 nm to 1530 nm. In this wavelength region, since strong attenuation due to water vapor does not occur, it is possible to suppress propagation attenuation of illumination light while suppressing disturbance factors. Therefore, it is possible to realize long distance ranging with particularly high accuracy.

  Furthermore, it is more preferable that the illumination light has a center wavelength of 1440 nm or more and less than 1490 nm. In this wavelength region, sunlight is more strongly attenuated. For this reason, disturbance due to sunlight can be further suppressed, and further accurate distance measurement can be realized.

  The wavelength bandwidth of the illumination light is not particularly limited in this embodiment. However, since attenuation of light due to resonance absorption of water vapor occurs in a narrow band, it is preferable that the wavelength band of illumination light be narrow. For example, the wavelength bandwidth is 10 nm or less, preferably 1 nm or less.

(Second Embodiment)
The TOF distance measuring device of this embodiment has high measurement accuracy even in rainy weather. FIG. 8A shows the intensity of sunlight on the ground at wavelengths from 1300 nm to 1500 nm, and FIG. 8B shows the absorption coefficient of water in the same wavelength region.

  As shown in FIG. 8A, the sunlight on the ground is strongly attenuated in the wavelength range of 1350 nm to 1410 nm. On the other hand, the absorption of water becomes significant at 1380 nm or more, and becomes maximum at about 1450 nm. Therefore, by setting the wavelength of the illumination light emitted from the light source in the range of 1350 nm to 1380 nm, the distance measurement enables accurate distance measurement by suppressing attenuation of the illumination light even when rainy weather or fog occurs. An apparatus can be realized.

The distance measuring device and the distance measuring method disclosed in the present application are suitably used for distance measuring devices such as riders and range image sensors used in various applications. Moreover, it is used suitably for the ranging apparatus used outdoors, such as a vehicle-mounted range image sensor.

101 Distance measuring device 111 Light source 112 Detector 113 Control device 114 Signal processor 151, 151A, 151B Object 152 Illumination light 153, 153A, 153B Reflected light

Claims (10)

A light source that emits illumination light having a center wavelength of 1290 nm or more and less than 1330 nm toward an object;
A detector for detecting the reflected light of the illumination light by the object, and measuring a distance to the object based on a phase difference between the illumination light emitted from the light source and the reflected light detected by the detector apparatus. A light source that emits illumination light having a center wavelength of 1440 nm or more and 1530 nm or less toward an object;
A detector for detecting the reflected light of the illumination light by the object, and measuring a distance to the object based on a phase difference between the illumination light emitted from the light source and the reflected light detected by the detector apparatus.   The distance measuring apparatus according to claim 2, wherein a center wavelength of the illumination light is in a range of 1440 nm or more and less than 1490 nm. A light source that emits illumination light having a center wavelength of 1350 nm or more and less than 1380 nm toward an object;
A detector for detecting the reflected light of the illumination light by the object, and measuring a distance to the object based on a phase difference between the illumination light emitted from the light source and the reflected light detected by the detector apparatus. The light source emits the intensity-modulated illumination light;
The detector is an image sensor in which a plurality of pixels are arranged two-dimensionally,
The distance measuring device according to claim 1, wherein a distance image is generated based on the phase difference. Emitting illumination light having a center wavelength of 1290 nm or more and less than 1330 nm toward the object,
The reflected light from the object of the illumination light is detected by a detector,
A distance measuring method for measuring a distance to the object based on a phase difference between illumination light emitted from the light source and reflected light detected by the detector. Emitting illumination light having a center wavelength of 1440 nm or more and 1530 nm or less toward the object,
The reflected light from the object of the illumination light is detected by a detector,
A distance measuring method for measuring a distance to the object based on a phase difference between illumination light emitted from the light source and reflected light detected by the detector.   The distance measuring method according to claim 7, wherein a center wavelength of the illumination light is in a range of 1440 nm or more and less than 1490 nm. Emitting illumination light having a center wavelength of 1350 nm or more and less than 1380 nm toward the object,
The reflected light from the object of the illumination light is detected by a detector,
A distance measuring method for measuring a distance to the object based on a phase difference between illumination light emitted from the light source and reflected light detected by the detector. The illumination light is intensity modulated,
The detector is an image sensor in which a plurality of pixels are arranged two-dimensionally,
The distance measuring method according to claim 6, wherein a distance image is generated based on the phase difference.

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