JP2001112026A - Three-dimensional image detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-dimensional image detector that emits a range finding light to detect the distance and uses one light source to efficiently conduct range finding and optical communication. SOLUTION: A light source 14 emits a pulse-modulated laser beam according to a binary data stream of transmission data. A photo diode provided inside an image pickup lens 11 receives the laser beam reflected on an object. The signal charges produced by the laser beam received by the photo diode are stored matching the trail of the pulse of the pulse-modulated laser beam. The distance to the object is detected from the stored signal charges. On the other hand, a light receiving device 51 placed in the emitter area of the laser beam receives and detects the pulse-modulated laser beam and outputs it to a computer 50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a three-dimensional image detecting apparatus for detecting a three-dimensional shape of a subject using a light propagation time measuring method.

[0002]

2. Description of the Related Art A subject is imaged by a three-dimensional image detecting device,
In order to obtain a three-dimensional image of a subject from the detected distance data and image data, it is necessary to provide high image processing capability and sufficient storage capacity. However, if circuits and equipment necessary for this are provided, the size of the device becomes large, so that it is difficult to obtain a three-dimensional image with a small and lightweight three-dimensional image detecting device. Therefore, the conventional three-dimensional image detecting apparatus is connected to a computer by an interface cable, and detected data is sequentially sent to the computer via the cable and processed on the computer.

[0003]

In order to form a three-dimensional image of a subject from detected distance data and image data,
The subject must be imaged from multiple directions and synthesized. However, if the three-dimensional image detection device and the computer are connected by a cable, the movable range of the three-dimensional image detection device is limited, and it is difficult to perform imaging from multiple directions. It also hinders operator movement and equipment operation.

An object of the present invention is to provide a three-dimensional image detecting apparatus which can transfer data to a computer without using a cable and has high communication efficiency.

[0005]

According to the present invention, there is provided a three-dimensional image detecting apparatus comprising: a light source for irradiating light; an image sensor capable of accumulating electric charges corresponding to a received light amount; Distance light detecting means for irradiating distance light, receiving reflected light from the object by the image sensor, detecting the distance to the object based on signal charges accumulated by the reflected light, and irradiating communication light by controlling the light source Information communication means for performing optical communication using a space as a transmission path, accumulating signal charges in an image sensor in synchronization with emission of communication light, and using communication light as distance measuring light to communicate with communication light. It is characterized in that the light from the light source is emitted while being superimposed on the distance measuring light.

Preferably, in the distance information detecting means, the distance measuring light is repeatedly irradiated a predetermined number of times, and a signal charge is accumulated in the image pickup element at each repetition.

The light emission of the communication light in the information transmitting means preferably corresponds to either binary data 1 or 0. Preferably, the communication light is a pulse-modulated laser light. The data stream transmitted by the communication light preferably includes a data separation signal for separating the data stream by the number of bits of data.

[0008] The three-dimensional image detection device preferably comprises a plurality of photoelectric conversion elements in which the image pickup element accumulates electric charges in accordance with the amount of received light, and a signal charge holding portion provided adjacent to the photoelectric conversion elements. At this time, the accumulation of the signal charges in the imaging element preferably starts at the fall of the charge sweeping signal for sweeping out the charges accumulated in the photoelectric conversion element, and transfers the charge accumulated in the photoelectric conversion element to the signal charge holding unit. The operation ends when the charge transfer signal falls. More preferably, the charge transfer signal rises at the same time as the fall of the charge sweeping signal.

For example, a charge transfer signal in a three-dimensional image detecting device is a logical product of a reference charge transfer signal, which is a periodic pulse signal, and a data synchronization pulse signal generated in synchronization with a falling edge of a pulse signal in a data train. Generated by The charge sweeping signal is generated by the logical product of a data synchronization pulse signal and a reference charge sweeping signal which is a pulse signal having the same cycle as that of the reference charge transfer signal and delayed by a half cycle. At this time, the data synchronization pulse signal is synchronized with the reference sweep signal, and its pulse width is equal to one cycle width of the reference charge transfer signal.

Preferably, the accumulation of the signal charges is performed in accordance with the fall of the communication light.

Preferably, the distance measuring period, which is a period in which the distance measuring light is repeatedly irradiated a predetermined number of times, includes a data transfer section in which the distance measuring light and the communication light are superimposed and irradiated, and a distance measuring light in the data transfer section. When the number of times of irradiation is less than the predetermined number, a light amount correction section for irradiating distance measurement light for supplementing the number of times is provided.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a camera-type three-dimensional image detection device according to a first embodiment of the present invention.

On the front of the camera body 10, a finder window 12 is provided at the upper left of the taking lens 11, and a flash 13 is provided at the upper right. On the upper surface of the camera body 10, right above the taking lens 11, a distance measuring light emitting device (light source) 14 for irradiating laser light, which is distance measuring light, is provided. A release switch 15 and a liquid crystal display panel 16 are provided on the left side of the light emitting device 14 for distance measurement, and a mode switching dial 17 and a V / D mode switching switch 1 are provided on the right side.
8 are provided. The IC on the side of the camera body 10
A card insertion slot 19 for inserting a recording medium such as a memory card is formed, and a video output terminal 20 is provided.

FIG. 2 is a block diagram showing a circuit configuration of the camera shown in FIG. An aperture 25 is provided in the taking lens 11. The opening of the aperture 25 is determined by the iris drive circuit 2.
Adjusted by 6. The focus adjustment operation and the zooming operation of the taking lens 11 are controlled by a lens drive circuit 27.

An image pickup device (C
CD) 28 is provided. A subject image is formed on the CCD 28 by the photographing lens 11, and charges corresponding to the subject image are generated. Operations such as a charge accumulation operation and a charge read operation in the CCD 28 are controlled by the CCD drive circuit 30. The charge signal, that is, the image signal, read from the CCD 28 is amplified by the amplifier 31 and the A / A
The analog signal is converted into a digital signal in the D converter 32. The digital image signal is output from the imaging signal processing circuit 3
In the image memory 3, processing such as gamma correction is performed.
4 is temporarily stored. The iris drive circuit 26, the lens drive circuit 27, and the imaging signal processing circuit 33 are controlled by a system control circuit 35. The CCD driving circuit 30 is provided with a CCD output from the V / D switching circuit 22.
It is controlled by the driving pulse.

The image signal is read from the image memory 34 and supplied to the LCD drive circuit 36. The LCD drive circuit 36 operates in accordance with the image signal, and thereby the image display L
An image corresponding to the image signal is displayed on the CD panel 37.

If the camera is connected to a monitor device provided outside the camera body 10 by a cable, the image memory 34
Are read from the TV signal encoder 38,
It can be transmitted to the monitor device via the video output terminal 20. The system control circuit 35 is connected to the interface circuit 40, and the interface circuit 40 is connected to the interface connector 21. Therefore, if the camera is connected to a computer provided outside the camera body 10 via an interface cable, the image signal read from the image memory 34 can be transmitted to the computer. The system control circuit 35 is connected to the image recording device 43 via the recording medium control circuit 42. Therefore, the image signal read from the image memory 34 is
Can be recorded on a recording medium M such as an IC memory card mounted on the PC.

The light emitting device 14 includes a light emitting element 14a and an illumination lens 14b. The light emitting operation of the light emitting element 14a is controlled by a light emitting element control circuit 44. The light emitting element control circuit 44 is controlled by a pulse signal from the delay circuit 45. This pulse signal is obtained by delaying the data pulse signal output from the data pulse output circuit 29 by the delay circuit 45. The data pulse signal is obtained by transmitting transmission data as a time-series pulse signal.

The light emitting element 14a is a laser diode (L
D), and the irradiated laser light is obtained by superposing distance measuring light and communication light. This laser light is applied to the entire subject and an area including a light receiver for optical communication via the illumination lens 14b. The laser beam reflected by the subject enters the photographic lens 11 and is detected by the CCD 28, whereby the distance information of the subject is detected. Further, since the communication light is superimposed on the irradiated laser light, the data is transmitted to the computer when the photodetector connected to the computer detects and receives the laser light. The data pulse signal output from the data pulse output circuit 29 to the delay circuit 45 is also output to the CCD drive pulse conversion circuit 46 and the count circuit 39 at the same time.

In the D-mode CCD drive pulse generation circuit 23, a reference CCD drive pulse which is used as a reference when detecting distance information is generated and output to the CCD drive pulse conversion circuit 46. In the CCD drive pulse conversion circuit 46, the CCD
The reference CCD drive pulse is converted based on the data pulse signal so that the accumulation of the signal charge in is performed in synchronization with the light emitting operation of the light emitting element 14a based on the data pulse signal. The converted CCD drive pulse is
The signal is output to the CCD driving circuit 30 via the / D switching circuit 22.

In the V-mode CCD drive pulse generating circuit 24, a CCD drive pulse for performing a normal video control is generated.
Output to 0. The V / D switching circuit 22 sends the CCD driving pulse from the V-mode CCD driving pulse generating circuit 24 or the CCD driving pulse converting circuit 46 to the CCD driving circuit 30 in accordance with the mode set by the V / D mode switch 18. Output. V / D switching circuit 22, V mode C
The CD drive pulse generation circuit 24 and the D mode CCD drive pulse generation circuit 23 include a system control circuit 35.
Is controlled by

The system control circuit 35 is connected to a switch group 45 including a release switch 15, a mode switching dial 17, and a V / D mode switching switch 18, and a liquid crystal display panel (display element) 16.

FIG. 3 schematically shows a state when detecting distance information and performing optical communication.

The detection of distance information is performed by irradiating the subject S with laser light from the light emitting device 14 and receiving the reflected light from the subject S via the imaging lens 11 by the CCD 28 (FIG. 2). On the other hand, when transmitting data to the computer 50, the laser light emitted from the light emitting device
The detection is performed by detecting light received by the light receiver 51 disposed in the inside. The light detected by the light receiver 51 is converted into an electric signal, sent to the computer 50 as received data, subjected to predetermined processing, and displayed on a display or the like (not shown).

Next, the principle of distance measurement in the present embodiment will be described with reference to FIGS. FIG.
, The horizontal axis is time t.

The distance measuring light output from the distance measuring device B is reflected by the subject S and received by a CCD (not shown). The distance measuring light is a pulsed light having a predetermined pulse width H, and therefore, the reflected light from the subject S is also a pulsed light having the same pulse width H. The rise of the reflected light pulse is delayed by a time δ · t (δ is a delay coefficient) from the rise of the distance measuring light pulse. Since the ranging light and the reflected light have traveled twice the distance r between the distance measuring device B and the subject S, the distance r is given by r = δ · t · C / 2 (1) can get. Where C is the speed of light.

For example, a state in which reflected light can be detected from the rise of the pulse of the distance measuring light is determined, and the state is switched to an undetectable state before the reflected light pulse falls, that is, a reflected light detection period T is provided. And the received light amount A during the reflected light detection period T is a function of the distance r. That is, the light receiving amount A decreases as the distance r increases (the time δ · t increases).

In this embodiment, utilizing the above-described principle,
In each of a plurality of photodiodes (imaging elements) provided on the CCD 28 and two-dimensionally arranged, the received light amount A
, The distance from the camera body 10 to each point on the surface of the subject S is detected, and data of a three-dimensional image relating to the surface shape of the subject S is input collectively.

FIG. 6 is a diagram showing the arrangement of the photodiode 51 and the vertical transfer unit 52 provided on the CCD 28.
FIG. 7 is a cross-sectional view of the CCD 28 cut along a plane perpendicular to the substrate 53. This CCD 28 is a conventionally known interline type CCD, and uses a VOD for sweeping out unnecessary charges.
(Vertical overflow drain) method.

The photodiode 51 and the vertical transfer section 52 are formed along the surface of the n-type substrate 53. The photodiodes 51 are two-dimensionally arranged in a lattice, and the vertical transfer units 52 are provided adjacent to the photodiodes 51 arranged in a line in a predetermined direction (the vertical direction in FIG. 6). The vertical transfer section 52 has four vertical transfer electrodes 52a, 52b, 52c, and 52d for one photodiode 51. Therefore, in the vertical transfer section 52, four potential wells can be formed, and signal charges can be output from the CCD 28 by controlling the depths of these wells as conventionally known. The number of vertical transfer electrodes can be freely changed according to the purpose.

A photodiode 51 is formed in a p-type well formed on the surface of the substrate 53, and the p-type well is completely depleted by a reverse bias voltage applied between the p-type well and the n-type substrate 53. You. In this state, charges corresponding to the amount of incident light (reflected light from the subject) are accumulated in the photodiode 51. When the substrate voltage Vsub is increased to a predetermined value or more, the electric charge accumulated in the photodiode 51 is discharged to the substrate 53 side. On the other hand, when a charge transfer signal (voltage signal) is applied to the transfer gate unit 54, the charges accumulated in the photodiode 51 are transferred to the vertical transfer unit 52. That is, after the charges are swept to the substrate 53 side by the charge sweeping signal, the signal charges accumulated in the photodiode 51 are changed by the charge transfer signal to the vertical transfer unit 5.
It is transferred to the two sides. By repeating such an operation, signal charges are integrated in the vertical transfer unit 52, and a so-called electronic shutter operation is realized.

FIG. 8 is a timing chart in the distance information detecting operation. The distance information detecting operation in the present embodiment will be described with reference to FIGS. 1, 2, and 6 to 8. In the distance information detecting operation of the present embodiment, unlike the description of the principle of the distance measurement performed with reference to FIG. 5, in order to reduce noise due to the influence of external light, the distance measurement light is reflected from the falling edge of the pulse. The timing chart is configured so that the light can be detected, and the state is switched to the undetectable state after the pulse of the reflected light has fallen, but it is not different in principle.

A charge sweeping signal (pulse signal) S 1 is output in synchronization with the output of the vertical synchronization signal (not shown), whereby unnecessary charges accumulated in the photodiode 51 are swept toward the substrate 53. Then, the accumulated charge amount in the photodiode 51 becomes zero (reference S2). After the start of the output of the charge sweeping signal S1, a pulse-shaped ranging light S3 having a constant pulse width is output. The period T _S (pulse width) during which the ranging light S3 is output can be adjusted.
The adjustment is made so that the distance measurement light S3 is turned off almost simultaneously with the fall of the charge sweeping signal S1.

The distance measuring light S3 is reflected by the object, and
It is incident on D28. That is, although the reflected light S4 from the subject is received by the CCD 28, no charge is accumulated in the photodiode 51 while the charge sweeping signal S1 is being output (reference S2). When the output of the charge sweeping signal S1 is stopped and the charge transfer signal S9 is output almost simultaneously, the photodiode 51 starts to accumulate charges by receiving the reflected light S4 and transfer the charges to the vertical transfer unit 52. As a result, the signal charge S5 caused by the external light and the reflected light S4 is generated and accumulated in the photodiode 51 and is transferred to the vertical transfer unit 52. When the reflected light S4 disappears (reference S6), in the photodiode 51, the charge accumulation based on the reflected light ends (reference S7), but the charge accumulation due to only the external light continues (reference S8), and the accumulated charge Is transferred to the vertical transfer unit 52.

From the photodiode 51 to the vertical transfer unit 52
The transfer of the charges to is completed by the end of the output of the charge transfer signal S9 (reference S10). That is, although the charge accumulation continues in the photodiode 51 due to the presence of external light, the signal charge S11 accumulated in the photodiode 51 is transferred to the vertical transfer unit 52 until the output of the charge transfer signal S9 ends. . The charge S14 accumulated after the output of the charge transfer signal ends remains in the photodiode 51 as it is.

As described above, the period T _U1 from the end of the output of the charge sweeping signal S1 to the end of the output of the charge transfer signal S9.
During the period, the signal charge corresponding to the distance to the subject is accumulated in the photodiode 51. The charge accumulated in the photodiode 51 until the end of the reception of the reflected light S4 (reference S6) is transferred to the vertical transfer unit 52 as a signal charge S12 (hatched portion) corresponding to the distance information of the subject,
Other signal charges S13 are caused only by external light.

After a lapse of a predetermined time from the output of the charge transfer signal S9, the charge sweeping signal S1 is output again, and the unnecessary charges accumulated in the photodiode 51 after the transfer of the signal charges to the vertical transfer unit 52 are transferred to the substrate 53. Is discharged in the direction of. That is, accumulation of signal charges in the photodiode 51 is newly started. Then, the signal charge is transferred to the vertical transfer unit 52 during the charge accumulation period T _{U1 in} the same manner as described above.

The vertical transfer section 5 of such signal charges S11
The transfer operation to No. 2 is repeated a predetermined number of times until the next vertical synchronization signal is output. As a result, the signal charge S11 is integrated in the vertical transfer unit 52, and the signal charge S11 integrated in a period of one field (a period sandwiched between two vertical synchronization signals) is regarded as a period in which the subject is stationary. For example, it corresponds to distance information to the subject. Since the signal charge S13 is smaller than the signal charge S12, the signal charge S11 can be regarded as the signal charge S12.

The detection operation of the signal charge S11 described above relates to one photodiode 51, and such a detection operation is performed in all the photodiodes 51. As a result of the detection operation in the period of one field, the vertical transfer unit 52 adjacent to each photodiode 51
The distance information detected by the photodiode 51 is held in each of the parts. This distance information is output from the CCD 28 by a vertical transfer operation in the vertical transfer unit 52 and a horizontal transfer operation in a horizontal transfer unit (not shown), and is taken out of the CCD 28 as three-dimensional image data.

Next, the distance information detecting operation will be described with reference to FIG. 9 which is a flowchart of the distance information detecting operation.

When it is confirmed in step 101 that the release switch 15 is fully depressed, step 1 is executed.
02 is executed, video (V) mode and distance measurement (D)
It is determined which of the modes is selected. Switching between these modes is performed by operating the V / D mode switch 18.

When the D mode is selected, a ranging communication superimposition process described later is performed in step 103. Thereafter, in step 104, distance measurement light control is executed. That is, the light emitting device 14 is driven, and the pulsed ranging light S3 is output. Next, step 105 is executed, and the detection control by the CCD 28 is executed. That is, the distance information detection operation described with reference to FIG. 8 is performed, the charge sweeping signal S1 and the charge transfer signal S9 are alternately output, and the signal charge S11 of the distance information is integrated in the vertical transfer unit 52. The control of the light emitting element 14a and the CCD 28 performed in steps 104 and 105 is performed according to the LD drive pulse and the CCD drive pulse output in step 103.

In step 106, it is determined whether one field period has elapsed from the start of the distance information detection operation, that is, whether a new vertical synchronizing signal has been output.
If one field period has not ended, the process returns to step 103 and the next distance measurement communication superimposition process is performed.
When one field period ends, the process proceeds to step 107,
The signal charge S11 integrated by the vertical transfer unit 52 is transferred to the CCD 2
8 is output. This integrated signal charge is temporarily stored in the image memory 34 in step 108.
In step 109, the ranging light control is switched to the off state, and the light emitting operation of the light emitting device 14 is stopped.

In step 110, the arithmetic processing of the distance data is performed. In step 111, the distance data is stored in the image memory 34, and the detecting operation ends. On the other hand, when it is determined in step 102 that the V mode is selected, the distance measuring light control is switched to the off state in step 112, and the normal photographing operation (CCD video control) by the CCD 28 is turned on in step 113. , And the image data captured in step 114 is stored in the image memory 34, and this detection operation ends.

Next, the contents of the arithmetic processing executed in step 110 will be described with reference to FIG. It is assumed that a subject having a reflectance R is illuminated, and the subject is regarded as a secondary light source having a luminance I and is imaged on a CCD. At this time,
The output Sn obtained by integrating the charge generated in the photodiode during the charge accumulation time t is represented by the following formula: Sn = kRIt. Here, k is a proportionality constant, which varies depending on the F number, magnification, and the like of the taking lens.

As shown in FIG. 8, the charge storage time is T _U1 , the pulse width of the distance measuring light S3 is T _S , and the pulse width of the distance information signal charge S12 is T _D, and the charge storage during one field period is performed. When the time is to be repeated N times, the output SM _{10 obtained, SM 10 = Σk · R ·} I · T D = k · N · R · I · T D ··· (3) and composed. The pulse width T _D can be expressed as T _D = δ · t = 2r / C (4) At this time, the distance r to the subject can be expressed as follows: r = C · SM ₁₀ / (2 · k · N · R · I) (5) Therefore, if the proportional constant k, the reflectance R, and the luminance I are obtained in advance, the distance r can be obtained.

FIG. 10 is a flowchart of the ranging communication superimposing process executed in step 103.

In step 201, the presence or absence of transmission data is confirmed. If there is transmission data, data (for example, 8 bits) is read from the memory 34 in step 202 and converted into a data pulse signal in the data pulse output circuit 29, and the delay circuit 45, the count circuit 39, the CCD drive pulse Output to the conversion circuit 46.
In step 203, the data pulse signal is delayed by the delay circuit 45, and is output to the light emitting element control circuit 44 as an LD drive pulse for controlling the light emitting element 14a. At this time, in the CCD drive pulse conversion circuit 46, the D-mode CCD drive pulse generation circuit generates a charge so that charge can be accumulated in the photodiode 51 in accordance with the light emitting operation of the light emitting element 14a based on the data pulse signal. The CCD drive pulse is converted. Thereby, the ranging communication superimposition processing ends.

On the other hand, when it is determined in step 201 that there is no transmission data, in step 204, dummy data is generated by the system control circuit 35. This is because even when there is no data to be transmitted, laser light is emitted from the light emitting element 14a to detect distance information. In other words, the generated dummy data has no meaning as transmission information, and functions only as a signal for instructing a timing of emitting distance measuring light for detecting distance information. The dummy data is output to a data pulse output circuit 29 and converted into a data pulse signal.
It is output to the drive pulse conversion circuit 46.

Thereafter, in step 203, the data pulse signal of the dummy data is delayed by the delay circuit 45 and output to the light emitting element control circuit 44 as an LD drive pulse for controlling the light emitting element 14a. Also, the CCD driving pulse generated by the D-mode CCD driving pulse generation circuit is used to drive the CCD 51 so that the charge accumulation operation in the photodiode 51 is performed in accordance with the light emitting operation of the light emitting element 14a based on the data pulse signal of the dummy data. It is converted by the pulse conversion circuit 46. Thereby, the ranging communication superimposition processing ends.

Next, the ranging communication superimposing process will be described with reference to FIGS. FIG. 11 is a block diagram showing the circuit configuration of the CCD drive pulse conversion circuit 46 in more detail, and shows only a portion related to distance measurement communication superimposition processing in the block diagram of the entire camera (FIG. 2). FIG. 12 shows each pulse signal output from the circuit of FIG.
The sequence of the light emission pulse of the LD during the accumulation period in the photodiode 51 is shown.

FIG. 12A shows the data pulse output circuit 2
9 is a data pulse signal output from FIG. The pair of pulses S21 is a data separation signal for separating transmission data for each bit number of data. That is, the pulse S21
_Td from the rise of the pulse to the rise of the next pulse S21
Becomes one data section. The transmission data is, for example, 8-bit data. At this time, the transmission data is separated by a data separation signal S21 for each 8-bit data.
Data pulses of 8 bits in each data section is output in the interval T _P in the data section. Section _TP is 8
Each basic section corresponds to one bit of 8-bit data. In a certain basic section, the bit corresponding to the basic section is 1 when the pulse is on, and 0 when the pulse is off.

The eight-digit 2 added to each data section in FIG.
The radix represents 8-bit transmission data output in each data section. Each of these eight binary digits is represented by the interval T
One-to-one correspondence with the basic section of _P. That binary number 1 digit first basic intervals from the right interval T _P B1,2
The digit corresponds to the second basic section B2 from the right. Each digit corresponds to each basic section in order, and the eighth digit corresponds to the eighth (leftmost) basic section B8 from the right. For example, the transmission data output in the second data section from the left is 00101000, and since only the fourth and sixth digits are 1, the pulse is ON only in the fourth and sixth basic sections from the right. State and the off state in other basic sections. That is, the pulse S22 is the sixth digit, and the pulse S23 is the fourth digit.
Represents the first digit. Also, the 8-digit binary data in the third data section from the left is 111100001, and the upper three digits are consecutive 1s, so that the corresponding three basic sections from the left have pulses in the ON state. Becomes In this case, the upper three digits are one pulse S2 in which three pulses are successively formed.
It becomes 4.

These data pulses (FIG. 12A)
Is sent to the light emitting element drive circuit 44 as an LD drive pulse via the delay circuit 45. FIG. 12H illustrates a light emission pulse (LD light emission pulse) of the light emitting element (LD) 14a at this time. The LD emission pulse is a data pulse (FIG. 12A) delayed by Δt.
The light emitting element 14a emits light corresponding to the binary data in each data section.

Further, since the light emission pulse is also used as distance measuring light, the width of the basic section is the pulse width T _{S of the} distance measuring light.
Is equivalent to In the present embodiment, since the distance measurement is performed using the fall of the reflected light, the accumulation period in the photodiode 51 must be provided in accordance with the fall of the LD light emission pulse. That is, the CCD drive pulse conversion circuit 46 is the D-mode CCD drive pulse generation circuit 23.
Must be converted into a CCD drive pulse for accumulating electric charge in accordance with the falling edge of the LD light emission pulse in FIG.

The periodic pulses shown in FIGS. 12C and 12E correspond to the D-mode CCD drive pulse generation circuit 2.
3 is a reference CCD drive pulse generated in FIG. FIG.
FIG. 12C shows a reference sweep pulse serving as a reference for the charge sweeping operation, and FIG. 12E shows a reference transfer pulse serving as a reference for the charge transfer operation. The data pulse signal input to the CCD drive pulse conversion circuit 46 is first converted into a data synchronization pulse (FIG. 12B) by a data synchronization pulse generation circuit 47 and output to AND circuits 48 and 49. In the AND circuit 49, the data synchronization pulse and the reference sweep pulse output from the D-mode CCD drive pulse generation circuit 23 (FIG. 12)
The logical product (AND) with (c)) is obtained, and FIG.
Is converted to a pulse represented by This pulse is output to the V / D switching circuit 22 as a sweep pulse. On the other hand, AN
In the D circuit 48, the logical product (AND) of the data synchronization pulse and the reference transfer pulse (FIG. 12 (e)) output from the D mode CCD drive pulse generation circuit 23 is obtained, and FIG.
2 (f), and is output to the V / D switching circuit 22 as a transfer pulse.

The sweep pulse shown in FIG. 12D and the sweep pulse shown in FIG.
Is transferred to the CCD driving circuit 30 through the V / D switching circuit 22 as a CCD driving pulse, and is output to the CCD 28.
Of the photodiode 51 and the charge transfer operation. As described with reference to FIG. 8, charge accumulation in the photodiode 51 is performed during a period in which the charge transfer signal (transfer pulse) S9 that rises almost simultaneously with the fall of the charge sweep signal (sweep pulse) S1 is on. (Pulse width of S9) Since it is performed at T _U1 ,
When the data pulse is represented by a pulse as shown in FIG. 12A, the reference sweep pulse and the reference transfer pulse
(D), conversion is performed as shown in FIG. 12 (f), and charge accumulation in the photodiode 51 is performed at the timing shown in FIG. 12 (g). Thereby, the photodiode 51
The operation of accumulating the charges is always performed by the LD light emission pulse (FIG. 12).
(H)) is performed in accordance with the falling timing.

As described above, the light emission pulse of the light emitting element 14a is performed based on the data pulse signal corresponding to the transmission data, and the emitted laser light plays a role as communication light. At the same time, the laser light emitted by performing the charge accumulation operation in accordance with the fall of the light emission pulse plays a role as distance measuring light, and the communication light and the distance measuring light are superimposed.

Next, the light amount correction processing will be described with reference to FIGS.

As shown in FIG. 12A, the data pulse to be transmitted is different for each data section, so the number of falling edges of the light emission pulse is also different for each data section. In addition, the accumulation of the signal charge for the distance measurement is performed in accordance with the fall of the light emission pulse, and thus the number of times of charge accumulation differs for each data section. For example, the number of charge accumulations performed in each data section in FIG. 12G is four in the first data section from the left, twice in the second data section, and twice in the third data section. Therefore, since the total number of charge storage to be performed by the distance information detection operation (number of integrations of the signal charge) is different from the transmission data, also different output SM ₁₀ (total accumulated charge amount), the distance detection accuracy is deteriorated.

[0061] In this embodiment, the number of integrations of the signal charges performed by the distance information detection operation is constant, the output SM ₁₀ is light intensity correction processing to be independent of the transmission data.
FIG. 13 shows a sequence of a light emission operation performed in the distance information detection operation when performing the light amount correction processing.

In a distance measuring period (one field period) in which a light emitting operation for detecting distance information is performed, a data transfer section in which a light emitting operation is performed in accordance with a data pulse signal, and the number of integrations (total number of accumulations) in the distance measuring period. There is a light amount correction section in which a correction process for making the light amount constant is performed. Since the number of falling edges of the pulse of the data pulse signal output from the data pulse output circuit 29 is counted by the counting circuit 39, the number of accumulations (the number of integrations) in the data transfer section is counted at the end of the data transfer section. ing.
The remaining number of accumulations necessary for detecting the distance information is obtained from the counted number of accumulations, and light emission and accumulation for the remaining number of times are performed in the light amount correction section. For example, if the number of signal charge integrations performed in the distance information detection operation is 600,000, and if the number of accumulations (number of integrations) in the data transfer section is 300,000, 300,000 light emission and emission in the light amount correction section are performed. The accumulation is performed. If the number of accumulations (the number of integrations) in the data transfer section is 400,000, the number of accumulations is 2 in the light amount correction section.
Light emission and accumulation of 100,000 times are performed. Note that a switching period is provided between the data transfer section and the light quantity correction section to shift the processing to the light quantity correction processing.

Next, the sequence of the light emission pulse and the accumulation period in the light amount correction section will be described. FIG.
Are pulse signals output from the circuit of FIG. 11 in the light amount correction section, the accumulation period in the photodiode 51, L
4 shows a sequence of light emission pulses of D.

The system control circuit 35 calculates the number of times of light emission and accumulation required in the light quantity correction section from the number of falling light pulses (number of accumulations) of the light emission pulse in the data transfer section counted by the count circuit 39, and calculates the calculated number of times. To generate dummy data for performing light emission and accumulation. The generated dummy data is output as a data pulse (FIG. 14A) via the data pulse output circuit 29. Similar to the data pulse of the transmission data described with reference to FIG. 12, the data pulse of the dummy data is divided in 8-bit units by the data division signal S21, and the width of the basic section is the same. The dummy data is subjected to the same processing as the transmission data in the delay circuit 45 and the CCD drive pulse conversion circuit 46, and is sent to the light emitting element control circuit 44 and the CCD drive circuit 30 as an LD drive pulse and a CCD drive pulse, respectively. Is output. That is, when the data pulse of the dummy data is represented in FIG.
As shown in (d) and (f), the charge accumulation operation in the photodiode 51 is performed at the timing shown in FIG. The light emission pulse of the light emitting element 14a is shown in FIG.
As shown in (e), the output of the data pulse of the dummy data is delayed by Δt.

Since the basic sections are adjacent to each other in the output of the data pulse, when the pulses of the adjacent basic sections are in the ON state, the pulses output in the adjacent basic sections become one continuous pulse. For example, FIG.
As in S24 of (a), the basic section corresponding to the upper 3 bits is one pulse having a pulse width of 3 × T _S. Further, as described above, the accumulation of the signal charges for detecting the distance information of the subject is performed using the falling edge of the LD light emission pulse. Therefore, when the data pulse is 8 bits, the upper limit of the number of times that the signal charge including the distance information to the subject can be stored in one light amount correction section is when the data pulse is in the ON state every other bit and the number is 4 Times. FIG. 12A illustrates a case where the number of accumulations is, for example, less than 10 with respect to a fixed number of integrations in the distance information detection operation. In the first and second light amount correction sections from the left, the light emitting light sources 14a
And the accumulation of signal charges in the photodiode 51 is performed, and the remaining two times are performed in the third light amount correction section.

Next, the receiving operation of the optical communication executed on the computer 50 will be described with reference to FIG.

When the light emitting pulse (FIG. 12 (h)) of the light emitting element 14a is detected by the light receiving device 51 at step 301, the data pulse signal transmitted from the light emitting device 14 is detected by the light receiving device 51 at step 302. Be started. When a series of data has been received in step 302, the process proceeds to step 303. If the received data is image data or distance data of a subject, image processing or the like is performed in step 303, and if necessary, the computer 50
Is output to a display or the like connected to. Step 3
At 04, it is determined whether the receiving operation is to be ended. For example, if the end button assigned to a key such as the keyboard of the computer 50 is pressed, the receiving operation ends. If the end button is not pressed, step 30
It returns to 1 and enters the reception standby state again.

In this embodiment, the operation of accumulating charges in the photodiode 51 is performed by an LD light emission pulse (FIG. 12).
Although (h)) is performed almost simultaneously with the fall, the accumulation operation may be synchronized with the fall or rise of the LD emission pulse with a certain phase difference.

As described above, according to the present embodiment, optical communication and distance detection can be performed by using one light emitting device 14, and optical communication and distance detection can be performed by superimposing communication light and distance measurement light. Can be done simultaneously.

[0070]

As described above, according to the present invention, it is possible to obtain a three-dimensional image detecting apparatus which can transfer data to a computer without using a cable and has high communication efficiency.

[Brief description of the drawings]

FIG. 1 is a perspective view of a camera-type three-dimensional image detection device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit configuration of the camera shown in FIG.

FIG. 3 is a diagram schematically showing a state when data is transmitted by a distance information detection operation and optical communication.

FIG. 4 is a diagram for explaining the principle of distance measurement using distance measurement light.

FIG. 5 Distance measuring light, reflected light, gate pulse, and CCD
FIG. 4 is a diagram showing a distribution of the amount of light received by the light source.

FIG. 6 is a diagram illustrating an arrangement of a photodiode and a vertical transfer unit provided in a CCD.

FIG. 7 is a cross-sectional view of the CCD cut along a plane perpendicular to the substrate.

FIG. 8 is a timing chart of a distance information detecting operation for detecting data relating to a distance to a subject.

FIG. 9 is a flowchart of a distance information detecting operation.

FIG. 10 is a flowchart of a ranging communication superimposing process.

FIG. 11 is a block diagram illustrating a configuration of a circuit related to distance measurement communication superimposition processing.

FIG. 12 shows a data pulse, an accumulation period, and L during data transfer.
It is a figure which shows the sequence of D light emission pulse etc.

FIG. 13 is a diagram schematically illustrating a relationship between a data transfer section and a light amount correction section during a distance measurement period.

FIG. 14 shows a data pulse, an accumulation period, and an LD during light quantity correction.
It is a figure showing a sequence of a light emission pulse etc.

FIG. 15 is a flowchart of a receiving operation executed by the computer.

[Explanation of symbols]

 14 light emitting device 51 photodiode

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 27/148 G02B 7/11 F H04B 10/105 G03B 3/00 A 10/10 H01L 27/14 B 10 / 22 H04B 9/00 R H04N 5/225

Claims (11)

[Claims] A light source for irradiating light; an image sensor capable of accumulating electric charge according to a received light amount; controlling the light source so as to irradiate a subject with ranging light; Distance information detecting means for detecting the distance to the subject based on the signal charge accumulated by the reflected light, received by the image sensor, and irradiating communication light by controlling the light source, thereby setting the space as a transmission path. An information transmitting unit for performing optical communication, wherein the signal charge is accumulated in the image sensor in synchronization with emission of the communication light, and the communication light and the distance measurement are performed by using the communication light as distance measurement light. A three-dimensional image detection device, wherein light is emitted from the light source in a superimposed manner. 2. The three-dimensional apparatus according to claim 1, wherein the distance information detecting means repeatedly irradiates the distance measuring light a predetermined number of times, and accumulates a signal charge in the image sensor at each repetition. Image detection device. 3. The three-dimensional image detecting apparatus according to claim 1, wherein, in the information transmitting means, the emission of the communication light corresponds to one of binary data 1 and 0. 4. The three-dimensional image detecting device according to claim 1, wherein the communication light is a pulse-modulated laser light. 5. The three-dimensional image detection apparatus according to claim 4, wherein the data sequence transmitted by the communication light includes a data segmentation signal for segmenting the data sequence for each bit number of data. . 6. The image pickup device according to claim 1, wherein the image pickup device comprises a plurality of photoelectric conversion elements for accumulating electric charges according to the amount of received light, and a signal charge holding portion provided adjacent to the photoelectric conversion elements. 3. The three-dimensional image detection device according to item 1. 7. The accumulation of the signal charge in the image pickup device starts at a fall of a charge sweeping signal for sweeping out the charge accumulated in the photoelectric conversion element, and the charge accumulated in the photoelectric conversion element is stored in the image pickup device. 7. The three-dimensional image detecting apparatus according to claim 6, wherein the operation is terminated when a charge transfer signal for transferring to the signal charge holding unit falls. 8. The three-dimensional image detection device according to claim 7, wherein the charge transfer signal rises simultaneously with a fall of the charge sweep signal. 9. The charge transfer signal is generated by a logical product of a reference charge transfer signal, which is a periodic pulse signal, and a data synchronization pulse signal generated in synchronization with a falling edge of the pulse signal of the data train. Wherein the charge sweep signal is generated by the logical product of the data synchronization pulse signal and a reference charge sweep signal that is a pulse signal of the same cycle delayed by half a phase from the reference charge transfer signal; 9. The three-dimensional image detecting apparatus according to claim 8, wherein a signal is synchronized with the reference sweep signal, and a pulse width thereof is equal to one cycle width of the reference charge transfer signal. 10. The method according to claim 1, wherein the accumulation of the signal charge is performed in accordance with a fall of the communication light.
3. The three-dimensional image detection device according to item 1. 11. A distance measurement period in which the distance measurement light is repeatedly irradiated for the predetermined number of times, a data transfer period in which the distance measurement light and the communication light are superimposed and irradiated, and a data transfer period. 3. The three-dimensional light source according to claim 2, further comprising: a light amount correction section in which the distance measuring light is irradiated to supplement the number of times of irradiation of the distance measuring light when the number of times of the distance measuring light is less than the predetermined number. Image detection device.