JP2002039716A - Depth map input device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a depth map input device which can obtain a highly precise depth map with a small light source power, read a signal accurately without being affected by a sensitivity modulation signal, and operate with drive timing in which consumption power by modulation driving is not increased. SOLUTION: This distance depth map device is equipped with a light source for irradiating an object with a scanning light subjected to luminance modulation, an image element array which converts a light reflected from the object to an electric signal and is subjected to sensitivity modulation synchronous with the luminance modulation, and an image element driving circuit which drives the image element array and reads a signal synchronously with the scanning of the scanning light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance image input device, and more particularly, to a distance measuring device that irradiates light to an object and receives reflected light to detect the distance to the object. The present invention relates to a distance image input device configured to capture distance information of an object as an image in real time.

[0002]

2. Description of the Related Art As one of distance measuring methods, there is a method of measuring the spatial propagation time of light (Time of Flight method; TOF method).

In order to two-dimensionally express the distance information of an object based on this TOF method, two-dimensionally scan the intensity-modulated spot light and receive it with one sensitivity modulation element, or A method is adopted in which the modulated light is area-illuminated and collectively received by a sensitivity modulation element array.

A method of acquiring a distance image (two-dimensionally arranged information on the depth of an object) in real time using a luminance modulation light source and a sensitivity modulation element will be described below.
R. Miyagawa et al.'S presentation (1995 IEEE
Works on Charge-Couple
d Devices and Advanced Im
age Sensors, April 20-22: "
Integration-Time Based Co
Mputational Image Sensor
s ") will be described as an example.

FIG. 1 shows a cross-sectional structure of one pixel in a light receiving section of a sensitivity modulation element used by Miyagawa et al.

When the incident light enters the photoelectric conversion unit 505 of the element from the opening of the light shielding layer 508, the photoelectric conversion unit 505
Generates photo-generated electrons according to the amount of incident light.

The photoelectric conversion unit 505 is formed below the MOS photogate 500 and is
05 are transferred to transfer gates 501 and 502
Through the charge storage unit 506 below the charge storage gate 503 and the charge storage unit 50 under the charge storage gate 504, respectively.
7 is transmitted.

At this time, the charge storage gates 503 and 50
4, a voltage higher than that of the photogate 500 is applied.
The transfer gates 501 and 502 are complementary. That is, when a transfer pulse is applied to the transfer gate 501, the transfer gate 502 is turned off.
A pulse is input so that 02 turns off.

By driving in this manner, the electrons generated in the photoelectric conversion unit 500 can be temporally selected and stored in the charge storage units 506 and 507 while sorting them.

Next, the principle of distance measurement using the sensitivity modulation element will be described with reference to FIG.

FIG. 6 shows the intensity of the intensity-modulated light at the time of light transmission and the intensity of light reflected from the object at the time of light reception, and transfer gates 501 and 502.
, The amount of signal charge generated by the light receiving unit 505 and the amount of charge stored in the storage units 506 and 507 over time.

Pulse modulated luminance modulated light and gate 50
1 are in phase and the transfer gate 502
Are 180 ° out of phase with the voltage applied to.

[0013] The reflected light is different from the luminance modulated light at the time of light transmission.
The phase is delayed by the time Δt required to reciprocate the distance R to the object.

When the reflected light reaches the light receiving section 505, an electric charge is generated in an amount proportional to the light intensity.

This charge is transferred to the transfer gate 501 and the gate 5
In response to ON / OFF of 02, each component having the same phase is distributed to storage units 506 and 507 via transfer gates 501 and 502, and charges Q1 and Q2 are stored.

At this time, the distance R to the object is the speed of light c,
Assuming that the modulation pulse width is T, R = c ・ Δt / 2 = (cT / 4) ・ 2Q2 / (Q1 + Q2) = (cT / 4) ｛{1- (Q1-Q2) / (Q1 + Q2)} (1) It is expressed as

Therefore, the distance to the object can be detected by detecting the charges in the storage units 506 and 507, respectively, and processing them based on equation (1).

As described above, in the distance measurement based on the TOF method, when a sensitivity modulation pixel of a type that distributes electric charges by turning on / off a gate (hereinafter, a charge distribution type pixel) is used, the distance to an object is distributed. Since the distance is obtained from the ratio between the charges Q1 and Q2, distance information can be obtained by one detection.

Next, a general XY addressing method for reading out pixel signals in a MOS image sensor will be described with reference to FIGS.

FIG. 7 shows a general configuration of a basic portion of an XY address type solid-state imaging device.

Here, the light receiving section is formed by a pixel array 700 in which pixels are arranged in m rows × n columns.

The vertical scanning circuit 704 receives a row selection signal φSEL.
Scanning is performed while outputting i and the row reset signal φRSi to the pixel array 700.

When resetting the signal of the pixel in the i-th row, when the row reset signal φRSi of the i-th row is input from the vertical scanning circuit 704 to the pixel array 700 and the signal of the pixel in the i-th row is read out. The i-th row selection signal φSELi is input to the pixel array 700 from the vertical scanning circuit 704.

The selected signal of the pixel in the i-th row is subjected to desired processing by the row parallel processing circuit 701, and then the processing result is stored in the line memory 702.

Thereafter, the horizontal scanning circuit 703 scans while sequentially selecting the signals stored in the line memory 702.

By sequentially performing this processing from the first row to the m-th row, signals of all pixels of the pixel array 700 can be scanned and read.

FIG. 8 shows the drive timing of such an XY address type solid-state imaging device.

First, the vertical scanning circuit 704 outputs the signal φSEL1
Is output, the pixels in the first row are selected, and the pixel signals are read out.

At this time, the row reset signal φRS1 of the first row has been output prior to φSEL1.
Is the signal accumulation time of the pixels in the first row.

When the signal reading of the pixels in the first row is completed, the pixels in the second row are selected, and the pixel signals are read.

In this case, like the pixels in the first row, φSE
The row reset signal φRS2 of the second row is output prior to L2.

To make the signal accumulation time for each pixel uniform, φ
The time difference between RS2 and φSEL2 is set to the same time difference as in the first row.

By performing such scanning up to the m-th row, signal reading of one frame is performed.

Although the illustration of the horizontal scanning pulse Hj of the horizontal scanning circuit 703 is omitted for the sake of simplicity, Hj (j = j
1, 2,. . . n) is from the signal reading of the i-th row to the (i +
It is output until the signal of one row is read.

Here, it should be noted that ordinary XY
In the address type solid-state imaging device, the time at which a signal is accumulated differs from row to row. More specifically, the time required to read a first row and the m-th row to be read first is at most one frame time. Is different.

[0036]

In the distance measuring method using the TOF method described above, in order to improve the distance measuring accuracy, it is necessary to accurately detect a reflected signal from a luminance modulation light source, that is, active illumination.

For example, in an environment where natural light exists, such as outdoors, it is desirable that the influence of the offset component of the signal due to natural light (external light) be made negligibly small as compared with the active illumination light component.

As a means for this, a band-pass filter that transmits only the wavelength of the illumination light is installed in front of the pixel, or two measurements are made by turning on / off the active illumination, and the difference between the two is taken. For example, a method of extracting only a signal component is used.

However, in any case, it is desired to make the active illumination component included in the photoelectric conversion signal relatively stronger than the external light component.

In order to obtain a range image by the TOF method, it is necessary to illuminate the target area two-dimensionally. Therefore, even if the illuminating light is two-dimensionally spread to a certain distance, it can be sufficiently exposed to external light. To maintain the intensity, a large light source power is required.

However, since it is necessary to ensure safety for eyes when a person is present near the light source, there is a limit to simply increasing the brightness of the light source.

As a method of relatively reducing the influence of external light, a method of shortening the light emission time of the light source and accumulating a signal only by the light emission time of the light source by an electronic shutter can be considered.

However, also in this case, there is a problem of safety to the eyes and a problem that it is difficult to reduce the size and power consumption of the light source because it is necessary to increase the instantaneous power of the light source.

The present invention pays attention to this point, and can obtain a high-precision distance image with a small light source power, and can secure the safety of eyes even when a person exists near the light source. It is an object to provide a device.

When distance measurement is performed using the TOF method,
Very high speed, e.g. It is necessary to modulate the sensitivity at 10 MHz as performed by Miyagawa et al.

At this time, the sensitivity modulation signal is mixed with the readout signal by a conductor for transmitting the sensitivity modulation signal to the pixel and a conductor for reading out the signal, or a capacitive coupling between the conductor for transmitting the sensitivity modulation signal and the substrate. However, there is a problem that the pixel signal cannot be read correctly.

When the modulation is performed at such a high speed, the power required for the modulation drive becomes very large.

Focusing on this point, the present invention provides a range image input device which can read out a signal accurately without being affected by a sensitivity modulation signal and operates at a drive timing at which power consumption by modulation drive does not increase. The task is to

The present invention has been made in view of the above circumstances, and it is possible to obtain a high-accuracy distance image with a small light source power and to accurately read out a signal without being affected by a sensitivity modulation signal. It is another object of the present invention to provide a range image input device that operates at a drive timing at which power consumption by modulation driving does not increase.

[0050]

According to the present invention, in order to solve the above-mentioned problems, there are provided: (1) a light source for irradiating an object with a luminance-modulated scanning light; and a light reflected from the object as an electric signal. And a pixel drive circuit that performs sensitivity conversion in synchronization with the luminance modulation, and a pixel drive circuit that drives and reads signals from the pixel array in synchronization with scanning by the scanning light. Is provided.

According to the present invention, in order to solve the above problems, (2) the scanning light is slit light, and the pixel array is a two-dimensional pixel array. A range image input device is provided.

According to the present invention, in order to solve the above problems, (3) the distance image input device has a function of pre-scanning with scanning light and inputting a preliminary distance image before inputting a distance image. The distance image input device according to (1) or (2) is provided.

According to the present invention, in order to solve the above-mentioned problems, (4) in the preliminary scanning, the scanning light has a light emission amount that is safe even if it is directly incident on human eyes. Item 3. A range image human power device according to item 3 is provided.

(5) The apparatus further comprises means for recording the scanning light transmission direction and luminance information, and the distance can be measured even in triangular distance measurement. (1) to (4)
The distance image input device according to any one of the above is provided.

(6) The distance image input device according to any one of (1) to (5), further comprising means for detecting a direction in which the scanning light is transmitted.

(7) The means for detecting the scanning light transmission direction includes means for dividing the scanning light, and detecting the scanning light transmission direction from the light receiving position by receiving the divided scanning light. The distance image input device according to (9), which includes a light receiving position detecting unit, is provided.

(8) A light source section capable of illuminating and scanning an object with slit light and capable of performing luminance modulation, and converting reflected light from the object into an electric signal to perform sensitivity modulation synchronized with the luminance modulation. A distance image input device, comprising: a pixel array arranged in an m × n matrix; and a pixel drive circuit that drives the pixel array and reads signals in synchronization with scanning of the slit light. Provided.

(9) The distance image input device according to the above (8), having a function of performing preliminary scanning of slit light and inputting a preliminary distance image before inputting a distance image. Is provided.

(10) The distance image input device according to the above (8) or (9), wherein a micromirror is used as a slit light scanning means.

(11) In the distance image input device according to any one of the above (8) to (10), sensitivity modulation is performed for each row or each column of the pixel array for a certain period, and a period for reading out a pixel signal. The distance image input device is provided, wherein the timing is set so that the sensitivity modulation and the illumination are stopped.

[0061]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) A first embodiment of the present invention will be described with reference to FIGS. 1, 2 and 3. FIG.

FIG. 1 is a block diagram showing the configuration of the range image input device according to the first embodiment of the present invention.

In FIG. 1, reference numeral 100 denotes a light source unit,
Reference numeral 101 is a luminance modulation light source, reference numeral 105 is a light source driving circuit, reference numeral 102 is a collimator lens, reference numeral 103 is a mirror for slit light scanning, and reference numeral 106
Is a mirror driving circuit for controlling the direction of the mirror 103, reference numeral 104 is a cylindrical lens, reference numeral 109 is a pixel array, and reference numeral 107 is a luminance modulation signal and a sensitivity modulation signal for performing distance measurement based on the TOF method. The mirror driving circuit 106 and the pixel driving circuit 108 send the light to the light source driving circuit 105 and the pixel driving circuit 108, respectively, and read the pixel signal in synchronization with the scanning of the slit light.
Reference numeral 110 denotes an image pickup optical system, reference numeral 111 denotes a signal processing circuit, reference numeral 112 denotes an object, and reference numeral 113 denotes an image pickup unit.

FIG. 2 shows the pixel array 109 of FIG.
This figure shows an example of a configuration in which an XY address type area sensor is composed of charge distribution type pixels arranged in n columns.

In synchronization with the change in the position of the received slit light, sensitivity modulation, reset, and signal reading are performed for each row by the pixel driving circuit 108.

The pixel output signal is converted into a time-series signal by horizontal scanning in the pixel drive circuit 108 after preprocessing such as offset removal in the signal processing circuit 111, and is converted into a distance image later.

FIG. 3 shows the sensitivity modulation period and the luminance modulation light irradiation period, the reset and readout timing of the pixel signal, and the horizontal scanning period in each row of FIG.

Here, the sensitivity modulation period indicates a period during which the sensitivity modulation signal is output from the pixel driving circuit 108, and the luminance modulation light irradiation period indicates a period during which the luminance modulation light is emitted from the light source 101. Inside, sensitivity modulation and luminance modulation are performed.

The horizontal scanning period is the horizontal scanning signal φ
H1, φH2,. . . φHn represents a period during which pixels are sequentially output from the pixel driving circuit 108 (horizontal scanning circuit). During this period, pixel output signals for one row are converted into a time-series signal.

The sensitivity modulation period, the luminance modulation light irradiation period, the timing of resetting and reading out the pixel signal are shifted in synchronization with the scanning of the slit light, and the sensitivity modulation period and the luminance modulation light irradiation period are set to the pixel signal in any row. The timing does not overlap with the reset and read timings.

With such an apparatus configuration, it is possible to generate a distance image based on the TOF method while scanning an object with slit light.

This embodiment is characterized in that a distance image can be generated by one detection by applying a charge distribution type pixel to an XY address type area sensor, and the accumulation time per pixel is reduced by using slit light. Therefore, the influence of external light is reduced, and power consumption is suppressed by using the above-described pixel drive timing, so that a highly accurate distance image can be acquired in real time with a small device.

The present embodiment can be variously modified.

For example, instead of the charge distribution type pixel, a CMD (Charge Modulation D) is used.
device) and AMI (Amplified MOS)
An amplifying solid-state imaging device such as an intelligent imager may be used.

However, in this case, it is necessary to repeat the above scanning twice.

Further, an elliptical diffusion plate may be used instead of the cylindrical lens. In this case, when an LD is used as a light source, the influence of speckle is reduced.

Further, a micro mirror may be used as the mirror 103.

The micromirror is a resonance type mirror in which the mirror portion and the mirror driving unit are integrated and is very small and does not require external control. However, the micromirror can be operated in a non-resonance mode. is there.

The present embodiment can be realized by operating in the non-resonant mode and stably controlling the operation by the controller 107.

In the charge distribution method, the total charge Q accumulated in the pixel is the sum of the divided charges Q1 and Q2 (Q
= Q1 + Q2), which represents the luminance information of the object and the direction of transmitting the slit light can be known from the control signal of the mirror. Therefore, if the luminance information is stored for each of the transmitting directions, It is also possible to measure the distance based on triangular distance measurement with the same circuit configuration from the luminance change in the light transmission direction in the pixel, and it is also possible to hybridize the active distance measurement method.

In this case, however, it is necessary to consider beforehand the width of the slit light or the distance to the object within a desired range so that the slit light is received by a plurality of rows of pixels.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
The embodiment will be described with reference to FIG.

FIG. 4 is a block diagram showing the configuration of the range image input device according to the second embodiment of the present invention.

In FIG. 4, reference numeral 401 denotes a beam splitter, and reference numeral 402 denotes a light receiving position detector for receiving light split by the beam splitter 401 and monitoring the direction of light transmission.

Here, a case where a micro mirror is used as the mirror 103 in the resonance mode will be described.

For this reason, the mirror driving device 1 shown in FIG.
06 is unnecessary.

The other points are the same as those described with reference to FIG.

In this configuration, the direction of the mirror, that is,
The transmitting direction of the slit light is monitored by the light receiving position detector 402 and sent to the controller 107 as a reference signal.
The pixel driving circuit 108 is operated synchronously based on this.

The feature of this embodiment is that the light receiving position detector 40
2, the position of the slit light can be accurately obtained, and the use of a micromirror allows the light source unit 1 to be obtained.
00 can be made small, and the light source unit 100 and the imaging unit 113 can be brought close to each other, so that the effect of occlusion is reduced.

Note that the present embodiment can be variously modified.

For example, since the micromirror is very small, the light source unit 100 and the imaging unit 113 can be configured by the same optical system.

The imaging lens 110 and the pixel array 10
An optical band-pass filter or a dichroic mirror may be provided between the first and second filters.

(Third Embodiment) Next, a third embodiment of the present invention will be described.
An embodiment will be described.

The device configuration according to the third embodiment is as follows.
Although any of the first embodiment and the second embodiment described above may be used, the preliminary scanning in which the slit light is preliminarily scanned and the image is input before acquiring the distance image is performed in the first embodiment. It is different from the embodiment and the second embodiment.

In this preliminary scanning, for example, when a person is in the vicinity of the light source, the light emission amount of the light source is suppressed to such an extent that even if slit light enters directly into the eyes, the human body is not affected.

By this preliminary scanning, a preliminary image or a preliminary distance image is obtained. If a person or an object is present near the light source, a warning is issued and the distance image input operation is stopped.

[0098] With this arrangement, when a person is in front of the distance at which the slit light diffuses until sufficient safety for the eyes can be obtained, the distance image is not input and danger can be avoided.

In addition, by synthesizing the preliminary distance image obtained by inputting the preliminary image and the distance image obtained by the original operation thereafter, it is possible to further expand the distance measurement range.

In particular, according to the present invention, a light source section capable of illuminating and scanning an object with slit light and capable of modulating brightness, and converting reflected light from the object into an electric signal, Mx which can perform sensitivity modulation synchronized with luminance modulation
It is characterized by having a pixel array arranged in a matrix of n, and a pixel driving circuit for driving the pixel array and reading out signals in synchronization with the scanning of the slit light.

According to the present invention, when an object is illuminated with illuminance that allows distance measurement, the amount of light from the light source can be reduced by using the slit light as compared with the case of area illumination. By performing the reading operation in synchronization with the scanning of light, it becomes possible to accumulate the optical signal only during the period of irradiation with the slit light, and the time from accumulating the signal charge to reading it out becomes short and constant.

In other words, even with the same light source power, when slit light is used, the illuminance increases as much as the illuminated area decreases, so that the accumulation time per pixel can be shortened and the effect of external light can be reduced. Can be.

According to a ninth aspect of the present invention, there is provided the distance image input device according to the eighth aspect, which has a function of preliminarily scanning slit light and inputting a preliminary distance image before inputting a distance image. And

According to the present invention, for example, by providing the function of reducing the light intensity of the light source and inputting the preliminary scanning of the slit light and the input of the preliminary distance image before inputting the above-mentioned distance image, for example, When the user is near, an operation of not inputting a distance image can be performed.

[0105]

Therefore, as described above, according to the present invention, a high-accuracy distance image can be obtained with a small light source power, and a signal can be accurately read out without being affected by a sensitivity modulation signal. In addition, it is possible to provide a range image input device that operates at a drive timing at which power consumption by modulation driving does not increase.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a range image input device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration example when the pixel array 109 of FIG. 1 is configured by an XY address type area sensor with charge distribution type pixels arranged in m rows × n columns.

FIG. 3 is a diagram illustrating a sensitivity modulation period and a luminance modulation light irradiation period, a reset and readout timing of a pixel signal, and a horizontal scanning period in each row in FIG. 2;

FIG. 4 is a block diagram illustrating a configuration of a range image input device according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating a conventional technology. Miyagawa
FIG. 4 is a diagram illustrating a cross-sectional structure of one pixel in a light receiving unit of a sensitivity modulation element used by a.

FIG. 6 is a diagram showing the light intensity of the luminance modulation light at the time of light transmission and the light intensity of the light reflected from the object at the time of light reception in FIG.
FIG. 6 is a diagram illustrating time-dependent changes in applied voltages 1 and 502, a signal charge amount generated in a light receiving unit 505, and a charge storage amount in storage units 506 and 507.

FIG. 7 is a diagram showing a general configuration of a basic portion of a conventional XY addressing solid-state imaging device.

FIG. 8 is a timing chart showing the drive timing of a conventional XY addressing solid-state imaging device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 100 ... Light source part, 101 ... Brightness modulation light source, 105 ... Light source drive circuit, 102 ... Collimator lens, 103 ... Mirror for slit light scanning, 106 ... Mirror drive circuit for controlling the direction of the mirror 103, 104 ... Cylindrical lens, 109: pixel array, 107: controller, 108: pixel driving circuit, 110: imaging optical system, 111: signal processing circuit, 112: target object, 113: imaging unit, 401: beam splitter, 402: light receiving position detector .

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/335 G02B 7/11 B 5J084 7/18 NZ (72) Inventor Masahiko Kato Hatagaya, Shibuya-ku, Tokyo 2-43-2 No.2 Olympus Optical Co., Ltd. F-term (reference) 2F065 DD01 DD02 DD11 FF04 FF09 HH05 JJ26 LL08 LL12 MM16 MM28 NN08 NN11 QQ31 UU05 UU06 2F112 AA09 BA04 BA06 CA12 DA15 DA28 EA03 FA05 FA12 FA20 BB03 BB15 BB16 CB22 CC04 CC08 CC13 FA61 GB16 5C024 AX02 BX00 CY17 EX41 EX42 EX50 EX51 GY31 GY42 GY44 HX50 HX58 JX02 JX06 JX41 5C054 CA06 CC05 EA01 FE28 HA05 5J084 AA05 AD01 CA07 BA07 BA07 BA04 BA07 DA08 EA31

Claims (11)

[Claims] 1. A light source for irradiating an object with scanning light whose luminance has been modulated, and for converting reflected light from the object into an electric signal,
A distance image input comprising: a pixel array that is sensitivity-modulated in synchronization with the luminance modulation; and a pixel drive circuit that drives and reads a signal to the pixel array in synchronization with scanning by the scanning light. apparatus. 2. The range image input device according to claim 1, wherein said scanning light is slit light, and said pixel array is a two-dimensional pixel array. 3. The distance image input device according to claim 1, wherein the distance image input device has a function of pre-scanning scanning light and inputting a preliminary distance image before inputting a distance image. apparatus. 4. The distance image human-powered apparatus according to claim 3, wherein in the preliminary scanning, the scanning light has a safe light emission amount even if it is directly incident on human eyes. 5. The apparatus according to claim 1, further comprising means for recording the scanning light transmission direction and luminance information, and enabling distance measurement in triangulation. 2. The distance image input device according to 1. 6. The range image input device according to claim 1, further comprising a unit configured to detect a direction in which the scanning light is transmitted. 7. A means for detecting the direction in which the scanning light is transmitted, a means for splitting the scanning light, and a light receiving means for receiving the divided scanning light and detecting a light transmitting direction of the scanning light from a light receiving position. 7. The range image input device according to claim 6, further comprising a position detecting unit. 8. A light source unit capable of luminance modulation for illuminating and scanning an object by slit light, and a light source capable of converting reflected light from the object into an electric signal and performing sensitivity modulation synchronized with the luminance modulation. A distance image input device, comprising: a pixel array arranged in a matrix of xn; and a pixel driving circuit that drives the pixel array and reads signals in synchronization with the scanning of the slit light. 9. The distance image input device according to claim 8, further comprising a function of performing preliminary scanning of slit light and inputting a preliminary distance image before inputting a distance image. 10. The distance image input device according to claim 8, wherein a micro mirror is used as a slit light scanning unit. 11. The distance image input device according to claim 8, wherein the sensitivity modulation is performed for each row or each column of the pixel array for a fixed period, and the period for reading out the pixel signal is the sensitivity modulation and the modulation. A distance image input device, wherein timing is set so that illumination stops.