JP6981043B2 - Distance measuring device - Google Patents

Description

The present disclosure relates to a technique for detecting the movement of a subject by using a distance measuring device for determining the distance from the flight time of light to the subject.

The following Patent Document 1 describes a technique of calculating a movement vector in the depth direction of a subject from two distance images acquired at different timings by using a phase type TOF sensor.
The phase type TOF sensor emits modulated light modulated by a pattern having a repetition period in space, and the modulated light receives incident light including return light reflected by an object and accumulates charge, and the charge is charged. The phase difference between the modulated light and the return light is measured based on the accumulated state, and the distance from the own device to the object is measured. TOF is an abbreviation for Time Of Fight.

Japanese Unexamined Patent Publication No. 2010-002326

However, as a result of detailed studies by the inventor, it has been found that there are the following problems when detecting motion using a conventional device.
That is, a general phase type TOF sensor creates one distance image from an image measured in four phases of 0 degree, 90 degree, 180 degree, and 270 degree. Therefore, four measurements are required to generate a distance image. Further, in the prior art, since two distance images are used for motion detection, it is necessary to acquire a total of eight images in 4 phases × 2 times, and it takes time to detect the motion of the subject.

The present disclosure provides a technique for suppressing the time required for detecting the movement of a subject by using a distance measuring device that obtains the distance from the flight time of light to the subject.

The ranging device according to one aspect of the present disclosure includes a light receiving unit (5), a light receiving control unit (6), and a processing unit (7). The light receiving unit has a plurality of pixels. The light receiving control unit has a plurality of pixels having different phases with respect to the irradiation light, with a part of the plurality of pixels of the light receiving unit as the first pixel group and at least a part of the plurality of pixels other than the first pixel group as the second pixel group. A shutter individually selected from the types of shutters is applied to the first pixel group and the second pixel group, and the light receiving unit is made to receive light. The processing unit obtains the distance to the subject reflecting the irradiation light from the detection result in the first pixel group, and detects the movement of the subject from the detection result in the second pixel group. Further, the light receiving control unit sequentially applies different types of shutters to the first pixel group, and continuously applies the same type of shutters to the second pixel group.

According to such a configuration, the image required for calculating the distance to the subject and the image required for detecting the movement of the subject are acquired in parallel by the first pixel group and the second pixel group. , The time required to detect the movement of the subject can be suppressed.

In addition, the reference numerals in parentheses described in this column and the scope of claims indicate the correspondence with the specific means described in the embodiment described later as one embodiment, and the technical scope of the present disclosure is defined. It is not limited.

It is a block diagram which shows the whole structure of a distance measuring device. It is a circuit diagram which shows the structure of a pixel. It is explanatory drawing which shows four kinds of shutters. It is a timing diagram which shows the operation of the light receiving control part in 1st Embodiment. It is explanatory drawing which shows how the 1st pixel group and 2nd pixel group are assigned, and how the phase of a shutter changes in each pixel group. It is explanatory drawing which shows the other allocation method of the 1st pixel group and 2nd pixel group, and how the phase of a shutter changes in each pixel group. It is explanatory drawing which shows the other allocation method of the 1st pixel group and 2nd pixel group, and how the phase of a shutter changes in each pixel group. It is explanatory drawing which shows the other allocation method of the 1st pixel group and 2nd pixel group, and how the phase of a shutter changes in each pixel group. It is explanatory drawing which shows the other allocation method of the 1st pixel group and 2nd pixel group, and how the phase of a shutter changes in each pixel group. It is a timing diagram which shows the operation of the light receiving control part in 2nd Embodiment. It is explanatory drawing which shows how the 1st pixel group and 2nd pixel group are assigned, and how the phase of a shutter changes in each pixel group. It is a timing diagram which shows the operation of the light receiving control part in 3rd Embodiment. It is explanatory drawing which shows how the 1st pixel group and 2nd pixel group are assigned, and how the phase of a shutter changes in each pixel group. It is a timing diagram which shows the operation of the light receiving control part in 4th Embodiment. It is explanatory drawing which shows how the 1st pixel group and 2nd pixel group are assigned, and how the phase of a shutter changes in each pixel group. It is explanatory drawing which shows the other allocation method of the 1st pixel group and 2nd pixel group, and how the phase of a shutter changes in each pixel group. It is explanatory drawing which shows the other allocation method of the 1st pixel group and 2nd pixel group, and how the phase of a shutter changes in each pixel group. It is a circuit diagram which shows the other structural example of a pixel. It is a timing diagram which shows the operation of a pixel. It is explanatory drawing which shows how the 1st pixel group and 2nd pixel group are assigned, and how the phase of a shutter changes in each pixel group. It is explanatory drawing which shows how the 1st pixel group and 2nd pixel group are assigned, and how the phase of a shutter changes in each pixel group. It is explanatory drawing which shows the modification of the method of allocating the 1st pixel group and the 2nd pixel group. It is explanatory drawing which shows the modification of the method of allocating the 1st pixel group and 2nd pixel group, and how the phase of a shutter changes in each pixel group. It is explanatory drawing which shows two kinds of shutters. It is a timing diagram which shows the operation of the light receiving control part when two kinds of shutters are used. It is explanatory drawing which shows 6 kinds of shutters. It is a timing diagram which shows the operation of the light receiving control part when 6 kinds of shutters are used. It is explanatory drawing which shows 8 kinds of shutters. It is a timing diagram which shows the operation of the light receiving control part when 8 kinds of shutters are used.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
[1. First Embodiment]
[1-1. composition]
The distance measuring device 1 is a so-called phase type TOF sensor, and is used, for example, to detect various objects existing around the vehicle, which are mounted on the vehicle and necessary for driving support control of the vehicle. .. TOF is an abbreviation for Time Of Fight. As shown in FIG. 4, the distance measuring device 1 emits light a plurality of times (four times in this embodiment) during one frame having a preset period, and the distance to the subject and the movement of the subject are obtained from the measurement results. The operation to detect is repeated.

As shown in FIG. 1, the distance measuring device 1 includes a light receiving unit 5, a light receiving control unit 6, and a processing unit 7. Further, the distance measuring device 1 may include a signal source 2, a driving unit 3, and a light emitting unit 4.
The signal source 2 generates a pulse signal at a preset measurement cycle.

The drive unit 3 drives the light emitting unit 4 according to the pulse signal generated by the signal source 2.
The light emitting unit 4 has a light emitting element, and outputs pulsed irradiation light according to the driving of the driving unit 3. As the light emitting element, a laser diode, a light emitting diode, or the like is used.

The light receiving unit 5 includes a plurality of light receiving elements arranged in a two-dimensional array. As the light receiving element, a photodiode, an avalanche photodiode, or the like is used. Hereinafter, each light receiving element and its peripheral circuit are collectively referred to as a pixel.

As shown in FIG. 2, the pixel includes a light receiving element 51, a capacitor 52, a shutter switch 53, a reset switch 54, and a reed switch 55. One end of the capacitor 52 is grounded and the other end is connected to the power supply via the reset switch 54. In the light receiving element 51, the anode is grounded and the cathode is connected to the ungrounded end of the capacitor 52 via the shutter switch 53. The ungrounded end of the capacitor 52 is further connected to the read line via a reed switch 55.

In the pixel configured in this way, when the reset switch 54 is turned on with the shutter switch 53 and the reed switch 55 turned off, the capacitor 52 is charged with the known voltage VDD. Further, by turning on the shutter switch 53 with the reset switch 54 and the reed switch 55 turned off, the electric charge generated according to the magnitude of the amount of light incident on the light receiving element 51 is accumulated in the capacitor 52. Since the shutter control signal is a signal synchronized with the modulated light, the amount of electric charge stored in the capacitor 52 changes according to the distance from the own device to the object. When the reed switch 55 is turned on with the shutter switch 53 and the reset switch 54 turned off, the potential at the non-grounded end of the capacitor 52 is read out from the read line and output to the processing unit 7.

Generally, a phase type TOF sensor requires charge accumulation for a time of several μs to several ms in order to measure the distance to an object. On the other hand, the modulation frequency of the modulated light emitted from the light emitting unit 4 is several tens of MHz. Therefore, since one cycle of modulation is about several tens of ns, charges are accumulated several thousand to several hundred thousand times in order to measure the distance with sufficient accuracy.

Returning to FIG. 1, the light receiving control unit 6 controls the shutter switch 53, the reset switch 54, and the reed switch 55 of each pixel according to the timing of the pulse signal from the signal source 2 (hereinafter, irradiation timing). As shown in FIG. 3, the shutter switch 53 is controlled by four types of gate signals G1 to G4 having different phases from each other. When the gate signals G1 to G4 are at a high level, the shutter switch 53 is turned on. Specifically, the gate signals G1 to G4 are defined as follows, assuming that the period required from the irradiation timing to the timing of receiving the reflected light from the maximum detection distance is expressed by a phase of 360 degrees. The gate signal G1 is a signal whose phase becomes high level only during the period of 0 degree to 180 degree. The gate signal G2 is a signal whose phase is high level only during the period of 90 degrees to 270 degrees. The gate signal G3 is a signal whose phase is high level only during the period of 180 degrees to 360 degrees. The gate signal G4 is a signal whose phase becomes high level only during the period of 0 degree to 90 degree and 270 degree to 360 degree.

The light receiving control unit 6 controls a plurality of pixels included in the light receiving unit 5 by dividing them into a plurality of pixel groups including the first pixel group A and the second pixel group B. Then, as shown in FIG. 4, the light receiving control unit 6 sequentially switches and uses the gate signals G1 to G4 for the first pixel group A every four times of irradiation of light in one frame. .. As a result, the first pixel group A supplies the four images acquired by using the four types of shutters having different phases to the processing unit 7. Further, the light receiving control unit 6 continuously uses the gate signal G1 for the first two irradiations for the second pixel group B, and the gate for the latter two irradiations. The signal G3 is used continuously. As a result, a pair of images obtained at different timings using the gate signal G1 and a pair of images obtained at different timings using the gate signal G3 are obtained, and these two pairs of images are the processing unit 7. Is supplied to.

The pixels belonging to the first pixel group A and the pixels belonging to the second pixel group B are configured to form a checkered pattern. Specifically, as shown in FIG. 5, the light receiving surface of the light receiving unit 5 has a unit pattern of a total of 4 pixels having a size of 2 vertical pixels and 2 horizontal pixels. Here, the pixels belonging to the first pixel group A are assigned to the upper left and lower right pixels of the unit pattern, and the pixels belonging to the second pixel group B are assigned to the upper right and lower left pixels of the unit pattern.

The wiring between the light receiving control unit 6 and the light receiving unit 5 may be wiring that controls the first pixel group A and the second pixel group B in group units, or may be controlled individually for each pixel. Wiring may be used. However, in the latter case, it is necessary to divide the pixel group by the control of the light receiving control unit 6.

The processing unit 7 obtains the distance from the four images supplied from the light receiving unit 5 to the subject reflecting the irradiation light based on the measured values of the pixels belonging to the first pixel group A. Further, the processing unit 7 calculates the movement of the subject from the four images supplied from the light receiving unit 5 based on the measured values of the pixels belonging to the second pixel group B. Further, since the distance cannot be calculated from the pixels belonging to the second pixel group B, the distance data may be interpolated based on the measured values of the surrounding first pixel group A. Since the details of the specific processing related to the calculation of the distance of the subject and the detection of the movement of the subject are described in detail in, for example, Patent Document 1 shown in the prior art, the description thereof is omitted here.

The processing unit 7 may include a well-known microcomputer having a CPU and a semiconductor memory (hereinafter, memory) such as RAM, ROM, and flash memory. In this case, various functions of the processing unit 7 are realized by the CPU executing a program stored in the non-transitional substantive recording medium. In this example, the memory corresponds to a non-transitional substantive recording medium in which a program is stored. In addition, when this program is executed, the method corresponding to the program is executed. The processing unit 7 may be provided with one microcomputer or may be provided with a plurality of microcomputers. The method for realizing the function of the processing unit 7 is not limited to software, and a part or all of the elements may be realized by using one or a plurality of hardware.

[1-3. effect]
According to the first embodiment described in detail above, the following effects are obtained.
(1a) In the distance measuring device 1, the light receiving unit 5 is divided into a first pixel group A and a second pixel group B, and different shutter control is performed for each pixel group, so that it is necessary to calculate the distance to the subject. Image and the image required to detect the movement of the subject are acquired in parallel. Therefore, it is possible to suppress the time required for the movement of the subject to be detected. That is, as shown in FIG. 4, in the conventional technique, since the motion is detected by comparing the distance images calculated for each frame, it takes two frames to detect the motion. In the embodiment, motion detection can also be completed in one frame.

(1b) In the distance measuring device 1, each pixel belonging to the first pixel group A measures with a four-phase shutter having a phase different by 90 degrees, and each pixel belonging to the second pixel group B has a phase of 180 degrees. Measurements are performed with shutters of two different phases, that is, 0 degrees and 180 degrees, or 90 degrees and 270 degrees. Thereby, the movement of the subject can be detected regardless of the phase difference between the irradiation light and the reflected light in the range of 0 degrees to 360 degrees.

(1c) In the distance measuring device 1, the pixels belonging to the first pixel group A and the pixels belonging to the second pixel group B are arranged to form a checkered pattern, so that the light receiving surface is arranged in the vertical direction and the horizontal direction. The same resolution can be obtained with. As shown in FIG. 20, the arrangement of the pixels belonging to the first pixel group A and the pixels belonging to the second pixel group B may be interchanged with each other. That is, the pixels belonging to the first pixel group A may be assigned to the upper right and lower left pixels of the unit pattern, and the pixels belonging to the second pixel group B may be assigned to the upper left and lower right pixels of the unit pattern.

[1-4. Modification example of how to switch gate signals G1 to G4]
The method of switching the gate signals G1 to G4 is not limited to the above.

In the first pixel group A, four types of shutters may be applied once for each of four light irradiations in one frame, and the order is not limited.
In the second pixel group B, for example, the order of the gate signal G1 and the gate signal G3 may be exchanged. In this case, as shown in FIG. 21, the gate signal G3 (that is, the phase 180 degree shutter) is continuously used for the first two irradiations, and the gate is used for the latter two irradiations. Signal G1 (ie, phase 0 degree shutter) may be used continuously. In addition, in FIG. 21, the arrangement of the pixel belonging to the first pixel group A and the pixel belonging to the second pixel group B in the checkered pattern in the unit pattern is opposite to that of the first embodiment, that is, shown in FIG. It is shown in the same way as the one.

Further, in the second pixel group B, for example, the gate signal G2 may be applied instead of the gate signal G1 and the gate signal G4 may be applied instead of the gate signal G3. That is, the gate signal G2 (that is, a shutter with a phase of 90 degrees) is continuously used for the first two irradiations, and the gate signal G4 (that is, a phase of 270 degrees) is used for the latter two irradiations. Shutter) may be used continuously. In this case, the order of the gate signal G2 and the gate signal G4 is further exchanged, the gate signal G4 is continuously used for the first two irradiations, and the gate signal is used for the latter two irradiations. G2 may be used continuously.

[1-5. Deformation example of pixel arrangement]
In the present embodiment, the pixels belonging to the first pixel group A and the pixels belonging to the second pixel group B are arranged to form a checkered pattern, but the present invention is not limited to this.

For example, as shown in FIG. 6, in the 4-pixel unit pattern, the pixels belonging to the first pixel group A are arranged in the left half of the unit pattern, and the pixels belonging to the second pixel group B are arranged in the right half of the unit pattern. It may be the one that has been used. In this case, the pixels belonging to both pixel groups are arranged to form a vertical striped pattern, and instead of the effect of (1c) described above, the effect that the resolution in the vertical direction of the light receiving surface can be improved can be obtained.

Further, as shown in FIG. 7, in the 4-pixel unit pattern, the pixels belonging to the first pixel group A are arranged in the upper half of the unit pattern, and the pixels belonging to the second pixel group B are arranged in the lower half of the unit pattern. It may be the one that has been used. In this case, the pixels belonging to both pixel groups are arranged to form a horizontal stripe pattern, and instead of the above-mentioned effect (1c), the effect that the resolution in the left-right direction of the light receiving surface can be improved can be obtained.

Further, as shown in FIG. 8, a region of interest (that is, ROI) is set on the light receiving surface, additional regions are set on both the left and right sides thereof, and pixels belonging to the first pixel group A are arranged in the region of interest. Pixels belonging to the second pixel group B may be arranged in the additional region. The area of interest may be fixed or dynamically set based on the position of the subject detected up to the previous frame. For example, when the front of the own vehicle is set as the area of interest, the distance can be accurately obtained for an object on the own lane detected in the area of interest, for example, the preceding vehicle. In addition, it is possible to accurately detect the movement of an object detected in the additional region, for example, a vehicle trying to cut into the own lane from an adjacent lane, a pedestrian trying to enter the road from a sidewalk, or the like. ..

As shown in FIG. 9, contrary to the case shown in FIG. 8, the pixels belonging to the first pixel group A may be arranged in the additional region, and the pixels belonging to the second pixel group B may be arranged in the region of interest. good.
Further, the pixels belonging to the first pixel group A and the pixels belonging to the second pixel group B may be collected and arranged at a specific portion in the light receiving surface. For example, as in the modified example 1 shown in FIG. 22, a specific partial region of the entire light receiving surface may be designated as the second pixel group B, and the other region may be designated as the first pixel group A. In this case, for example, the opening / closing of the door is monitored by the second pixel group B, and if the door is not opened / closed, the light emitting unit that illuminates the pixels other than the second pixel group B and the area other than the second pixel group B is stopped. By making it possible, it is possible to reduce the power consumption. Further, as in the modification 2 shown in FIG. 22, at least one of the first pixel group A and the second pixel group B may be present at a plurality of locations. Further, as in the modification 3 shown in FIG. 22, three or more types of pixel groups may exist. That is, there may be one or more pixel groups in the entire light receiving surface whose gate signals G1 to G4 are switched differently from those of the first pixel group A and the second pixel group B.

[2. Second Embodiment]
[2-1. Differences from the first embodiment]
Since the basic configuration of the second embodiment is the same as that of the first embodiment, the differences will be described below. It should be noted that the same reference numerals as those in the first embodiment indicate the same configuration, and the preceding description will be referred to.

In the second embodiment, the control by the light receiving control unit 6, particularly the control for the second pixel group B, is different from that in the first embodiment.
As shown in FIGS. 10 and 11, the light receiving control unit 6 in the present embodiment controls the first pixel group A in the same manner as in the case of the first embodiment. That is, the gate signals G1 to G4 are sequentially switched and used for each irradiation of light, and the same control is repeated for each frame.

The second pixel group B is controlled with two frames as one cycle, and the first frame is controlled in the same manner as in the first embodiment. That is, the gate signal G1 is continuously used for the first two irradiations, and the gate signal G3 is continuously used for the latter two irradiations. Then, in the second frame, the gate signal G2 is continuously used for the first two irradiations, and the gate signal G4 is continuously used for the latter two irradiations. .. As a result, two pairs of images acquired at different timings are obtained for a subject located at a distance corresponding to the gate signal G2 (that is, a shutter having a phase of 90 degrees) and the gate signal G4 (that is, a shutter having a phase of 270 degrees). Be done.

[2-2. effect]
According to the second embodiment described in detail above, the effects (1a) to (1c) of the above-mentioned first embodiment are exhibited.

The gate signals G1 to G4 used for the second pixel group B may be switched every frame or every plurality of frames.
[3. Third Embodiment]
[3-1. Differences from the first embodiment]
Since the basic configuration of the third embodiment is the same as that of the first embodiment, the differences will be described below. It should be noted that the same reference numerals as those in the first embodiment indicate the same configuration, and the preceding description will be referred to.

In the third embodiment, the control by the light receiving control unit 6 is different from that in the first embodiment.
As shown in FIGS. 12 and 13, the light receiving control unit 6 in the present embodiment controls two frames as one cycle. In the first frame, the same control as in the case of the first embodiment is executed. In the second frame, the positions of the pixels are exchanged between the first pixel group A and the second pixel group B, and the same control is executed.

[3-2. effect]
According to the third embodiment described in detail above, the effects (1a) to (1c) of the above-mentioned first embodiment are exhibited, and the following effects are further achieved.

(3a) According to the present embodiment, the positions of the pixels are switched for each frame in the first pixel group A and the second pixel group B, and all the pixels in which the respective pixel groups A and B form the light receiving surface are used. It will be used for measurement and detection. Therefore, according to the present embodiment, the resolutions in the vertical direction and the horizontal direction can be improved as compared with the cases of the first and second embodiments.

[4. Fourth Embodiment]
[4-1. Differences from the first embodiment]
Since the basic configuration of the fourth embodiment is the same as that of the first embodiment, the differences will be described below. It should be noted that the same reference numerals as those in the first embodiment indicate the same configuration, and the preceding description will be referred to.

In the fourth embodiment, the control by the light receiving control unit 6 and the configuration of the pixel group are different from those in the first embodiment.
As shown in FIGS. 14 and 15, in the present embodiment, the first pixel group A is divided into two first sub-pixel groups A1 and A2, and similarly, the second pixel group B is also two second. It is divided into sub-pixel groups B1 and B2. Then, in the 4-pixel unit pattern, the pixel belonging to the first sub-pixel group A1 is located at the upper left of the unit pattern, and the pixel belonging to the first sub-pixel group A2 is located at the lower right of the unit pattern. Further, in the unit pattern of 4 pixels, the pixel belonging to the second sub-pixel group B1 is located in the upper right, and the pixel belonging to the second sub-pixel group B2 is located in the lower left.

In addition, as in the modification 1 shown in FIG. 23, the arrangement of the first pixel group A and the second pixel group B may be exchanged. Further, as in the modification 2 shown in FIG. 23, the arrangements of the first sub-pixel groups A1 and A2 may be exchanged. Further, as in the modification 3 shown in FIG. 23, the arrangements of the second sub-pixel groups B1 and B2 may be exchanged.

The light receiving control unit 6 in the present embodiment performs irradiation twice for each frame. The first sub-pixel group A1 is controlled by the gate signal G1 in the first irradiation and the gate signal G3 in the second irradiation. The first sub-pixel group A2 is controlled by the gate signal G2 in the first irradiation and the gate signal G4 in the second irradiation. Further, in the second sub-pixel group B1, both the first and second irradiations are controlled by the gate signal G1, and in the second sub-pixel group B2, both the first and second irradiations are controlled by the gate signal G3. Will be done.

By applying the above control, in the first pixel group A, information for two phases can be obtained with one image, and information for four phases can be obtained only by acquiring two images. can. That is, the distance to the subject can be calculated using only two images.

Further, by the above control, information for two phases can be obtained in one image in the second pixel group B as well, and two images can be obtained regardless of the phase difference between the irradiation light and the reflected light of 0 degrees to 360 degrees. The movement of the subject can be obtained simply by acquiring the image of.

[4-2. effect]
According to the third embodiment described in detail above, the effects (1a) to (1c) of the above-mentioned first embodiment are exhibited, and the following effects are further achieved.

(4a) According to the present embodiment, the number of irradiations in one frame is only two times, so that the distance to the subject can be calculated and the movement of the subject can be calculated in a shorter time as compared with the first to third embodiments. Can be detected.

[4-3. Deformation example of pixel arrangement]
In the present embodiment, the pixels belonging to the first pixel group A and the pixels belonging to the second pixel group B are arranged to form a checkered pattern, but the present invention is not limited to this.

For example, as shown in FIG. 16, in the 4-pixel unit pattern, the pixel belonging to the first sub-pixel group A1 is in the upper left, the pixel belonging to the first sub-pixel group A2 is in the lower left, and the pixel belonging to the second sub-pixel group B1 is. Pixels belonging to the second sub-pixel group B2 may be arranged in the upper right and lower right.

Further, as shown in FIG. 17, in the 4-pixel unit pattern, the pixel belonging to the first sub-pixel group A1 is on the upper left, the pixel belonging to the first sub-pixel group A2 is on the upper right, and the pixel belonging to the second sub-pixel group B1 is used. The pixels belonging to the second sub-pixel group B2 at the lower left may be arranged at the lower right.

In the unit patterns shown in FIGS. 16 and 17, the arrangements of the first pixel group A and the second pixel group B may be exchanged or the first may be the same as in the case of the modified examples 1 to 3 shown in FIG. The arrangements of the sub-pixel groups A1 and A2 may be exchanged, or the arrangements of the second sub-pixel groups B1 and B2 may be exchanged.

[5. Other embodiments]
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and can be variously modified and implemented.

(5a) In the above embodiment, the configuration shown in FIG. 2 is illustrated as the configuration of each pixel, but the configuration is not limited to this. For example, as shown in FIG. 18, for one light receiving element 51, two sets of capacitors 52a, which are configured in the same manner as the capacitor 52, the shutter switch 53, the reset switch 54, and the reed switch 55 shown in FIG. 52b, shutter switches 53a, 53b, reset switches 54a, 54b, and reed switches 55a, 55b may be provided. In this case, as shown in FIG. 19, the two shutter switches 53a and 53b are operated in opposite phases. Then, the ratio of the values Da and Db read from both capacitors may be used as the measured value. Further, the number of capacitors constituting each pixel is not limited to the above-mentioned one and two, and may be three or more.

(5b) In the above embodiment, the shutter (that is, the gate signal) used for the second pixel group B is switched every two shutters, but the number of continuations of the same shutter may be three or more.
(5b) In the above embodiment, four types of shutters having different phases are used, but the number of types of shutters is not limited to this. For example, two types of shutters, six types of shutters, eight types of shutters, or other than these, two or more divisors of 360 may be represented by M, and M types of shutters may be used.

When two types of shutters are used, for example, as shown in FIG. 24, a gate signal (that is, a shutter having a phase of 0 degrees) whose phase is high level only during a period of 0 degrees to 180 degrees, and a phase of 180 degrees to 360 degrees. A gate signal (that is, a shutter with a phase of 180 degrees) that becomes a high level only for a period of degrees is used. In this case, the light emitting unit 4 irradiates twice for each frame. Then, as shown in FIG. 25, for example, the light receiving control unit 6 alternately switches and uses two types of gate signals for the first pixel group A for each irradiation. For the second pixel group B, control is performed with two frames as one cycle, and in the first frame, one gate signal (for example, a shutter having a phase of 0 degrees) is continuously used, and the second frame. In the frame of, the other gate signal (for example, a shutter having a phase of 180 degrees) is continuously used.

When six types of shutters are used, for example, as shown in FIG. 26, six types of gate signals having different phases of 60 degrees and having high levels for a period corresponding to 180 degrees are used. In this case, the light emitting unit 4 irradiates 6 times per frame. Then, as shown in FIG. 27, for example, the light receiving control unit 6 switches and uses six types of gate signals in order for the first pixel group A. For the second pixel group B, the gate signals having a phase difference of 180 degrees between the first three irradiations and the latter three irradiations are switched to be used. Regarding the second pixel group B, the irradiation may be divided into two times and switched so that three types of gate signals having different phases of 120 degrees are used.

When eight types of shutters are used, for example, as shown in FIG. 28, eight types of gate signals whose phases differ by 45 degrees and whose phases are high levels only for a period corresponding to 180 degrees are used. In this case, the light emitting unit 4 and the light receiving control unit 6 irradiate eight times per frame. Then, as shown in FIG. 29, for example, the light receiving control unit 6 sequentially switches and uses eight types of gate signals for the first pixel group A. For the second pixel group B, the gate signals having a phase difference of 180 degrees between the first four irradiations and the latter four irradiations are switched to be used. Regarding the second pixel group B, the irradiation may be divided into two times, and the irradiation may be switched so that four types of gate signals having different phases of 90 degrees are used.

That is, when using M types of shutters, if N = 360 / M and M types of gate signals whose phases differ by N degrees and whose phase is high only for a period corresponding to m × N degrees to m × N + 180 degrees are used. good. It should be noted that m = 0, 1, 2, ..., M-1.

Even when these M types of shutters are used, the same variations as those described in the above embodiment using the four types of shutters can be applied to the arrangement of the pixel groups and the method of switching the gate signal for each pixel group. ..

(5c) In the above embodiment, the arrangement of the pixels belonging to the first pixel group A and the pixels belonging to the second pixel group B is shown by a unit pattern of four pixels, but the present invention is not limited thereto. The pixel arrangement may have, for example, a more complex pattern represented by a unit pattern of 9 pixels or 16 pixels.

(5d) A plurality of functions possessed by one component in the above embodiment may be realized by a plurality of components, or one function possessed by one component may be realized by a plurality of components. .. Further, a plurality of functions possessed by the plurality of components may be realized by one component, or one function realized by the plurality of components may be realized by one component. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above embodiment may be added or replaced with the configuration of the other above embodiment. It should be noted that all aspects included in the technical idea specified from the wording described in the claims are embodiments of the present disclosure.

(5e) In addition to the distance measuring device described above, the present disclosure can be realized in various forms such as a system having the range measuring device as a component and a shutter control method.

1 ... ranging device, 2 ... signal source, 3 ... driving unit, 4 ... light emitting unit, 5 ... light receiving unit, 6 ... light receiving control unit, 7 ... processing unit, 51 ... light receiving element, 52, 52a, 52b ... capacitor, 53, 53a, 53b ... Shutter switch, 54, 54a, 54b ... Reset switch, 55, 55a, 55b ... Reed switch.

Claims (12)

It is a ranging device that performs phase-type TOF ranging.
A light receiving unit (5) having a plurality of pixels and
Some of the first pixel group of a plurality of pixels in which the light receiving portion has, at least some of the plurality of pixels other than the first pixel group as the second group of pixels, each irradiation of the plurality of the light in one frame , The shutter that is individually selected for the first pixel group and the second pixel group from among a plurality of types of shutters having different phases with respect to the irradiation light is applied to cause the light receiving unit to receive light. Control unit (6) and
Using a plurality of images obtained for each irradiation of the plurality of lights in one frame, the distance to the subject reflecting the irradiation light is obtained from the detection result in the first pixel group, and the second pixel group is obtained. The processing unit (7) that detects the movement of the subject from the detection result in
Equipped with
The light receiving control unit is configured to sequentially apply different types of shutters to the first pixel group and continuously apply the same type of shutters to the second pixel group. ,
Distance measuring device. The ranging device according to claim 1.
The pixels belonging to the first pixel group and the pixels belonging to the second pixel group are configured to form a checkered pattern.
Distance measuring device. The ranging device according to claim 1.
The pixels belonging to the first pixel group and the pixels belonging to the second pixel group are configured to form a vertical stripe pattern.
Distance measuring device. The ranging device according to claim 1.
The pixels belonging to the first pixel group and the pixels belonging to the second pixel group are configured to form a horizontal stripe pattern.
Distance measuring device. The ranging device according to claim 1.
In the light receiving surface formed by the light receiving portion, pixels belonging to the first pixel group are arranged in a set attention region, and pixels belonging to the second pixel group are arranged in a pair of additional regions located across the attention region. Configured to be placed,
Distance measuring device. The ranging device according to claim 1.
In the light receiving surface formed by the light receiving portion, pixels belonging to the second pixel group are arranged in a set attention area, and pixels belonging to the first pixel group are arranged in a pair of additional areas located across the attention area. Configured to be placed,
Distance measuring device. The distance measuring device according to any one of claims 1 to 6.
The light receiving control unit is configured to change the phase of the shutters of the pixels belonging to the second pixel group for each N shutter, where N is an integer of 2 or more.
Distance measuring device. The distance measuring device according to any one of claims 1 to 7.
The light receiving control unit is configured to periodically replace the pixels belonging to the first pixel group and the pixels belonging to the second pixel group.
Distance measuring device. The distance measuring device according to any one of claims 1 to 8.
The first pixel group has a plurality of first sub-pixel groups.
The light receiving control unit is configured to apply shutters having different phases to the plurality of first sub-pixel groups.
Distance measuring device. The distance measuring device according to any one of claims 1 to 9.
The second pixel group has a plurality of second sub-pixel groups.
The light receiving control unit is configured to apply shutters having different phases to the plurality of second sub-pixel groups.
Distance measuring device. The distance measuring device according to any one of claims 1 to 10.
As an integer in which M is 2 or more, N = 360 / M, m = 0, 1, 2, ..., M-1,
The light receiving control unit is configured to use M types of shutters corresponding to M timings represented by a phase of m × N degrees.
Distance measuring device. The distance measuring device according to claim 11.
M is a distance measuring device which is one of 2, 4, 6 and 8.

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