JP2000023014A - Image input device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image input device which can detect a three-dimensional form, etc., of an object, can photograph a two-dimensional image of the object and also can minimize power consumption. SOLUTION: When it's confirmed that a release switch 15 is completely pressed (101), it's decided whether a video(V) mode or a distance measurement (D) mode is selected (102). These V and D modes are switched to each other when a V/D mode changeover switch is operated. When the D mode is selected, a three-dimensional shape of an object is measured (103 to 110). Meanwhile, a two-dimensional image of the measuring object is photographed when the V mode is selected (111, 112). In the V mode, the range finder light is not controlled (103) and emission of the light is inhibited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image input device capable of detecting a three-dimensional shape or the like of an object to be measured by using, for example, a light propagation time measuring method and capturing a two-dimensional image.

[0002]

2. Description of the Related Art Conventionally, as an apparatus capable of detecting a three-dimensional shape of an object to be measured and photographing a two-dimensional image,
The one disclosed in WO 97/01111 is known. In this apparatus, the distance to the measured object is measured according to the principle of triangulation by irradiating the measured object with infrared rays and detecting the reflected light. At the same time as the distance measurement, a two-dimensional image of the measured object can be captured.

[0003]

This conventional apparatus is configured on the premise that a three-dimensional shape is measured.
The subject is always irradiated with infrared rays for distance measurement.
Therefore, even when only a two-dimensional image is required, there is a problem that power is always consumed for emitting infrared light.

An object of the present invention is to provide an image input device capable of detecting a three-dimensional shape or the like of an object to be measured and photographing a two-dimensional image, and suppressing power consumption as much as possible. .

[0005]

An image input apparatus according to the present invention irradiates an object to be measured with distance measuring light and detects reflected light from the object to be measured, thereby obtaining a distance to the object to be measured. Distance measuring means for measuring
It is characterized by comprising a photographing means for photographing a two-dimensional image, and a control means capable of selectively driving one of the distance measuring means and the photographing means.

Preferably, the control means prohibits the irradiation of the distance measuring light when driving the photographing means. The distance measuring means includes, for example, a light source that irradiates the object to be measured with distance measuring light, a plurality of photoelectric conversion elements that receive reflected light from the object to be measured and accumulate electric charges according to the amount of received light, and are adjacent to the photoelectric conversion element. The signal charge holding unit provided as above, and unnecessary charges accumulated in the photoelectric conversion element are swept out of the photoelectric conversion element to stop the operation,
A stored charge sweeping means for starting a signal charge storage operation in the photoelectric conversion element, a signal charge transfer means for transferring the signal charge stored in the photoelectric conversion element to a signal charge holding unit, a stored charge sweeping means, and a signal charge transfer A signal charge integration means for integrating the signal charge in the signal charge holding unit by alternately driving the means.

The photoelectric conversion element is, for example, a charge storage type,
They are arranged two-dimensionally. In this case, it is preferable that the photoelectric conversion element is formed along the substrate, and the accumulated charge sweeping means is configured to sweep unnecessary charges to the substrate side.

[0008] The signal charge holding section is preferably a vertical transfer section for outputting the signal charge to the outside of the three-dimensional image input device. The photoelectric conversion element and the signal charge holding unit are configured as, for example, an interline CCD having a vertical overflow drain structure.

The charge sweeping signal output by the accumulated charge sweeping means for sweeping out unnecessary charges and the charge transfer signal output by the signal charge transferring means for transferring signal charges are preferably pulse signals. It is. In this case, the light source outputs pulse-shaped ranging light having a predetermined pulse width, and during the first charge accumulation period from when the charge sweeping signal is output to when the charge transfer signal is output, the ranging light is output. Is output, the signal charge corresponding to the distance information is integrated in the signal charge holding unit.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a camera provided with an image input device according to an 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. A light emitting device (light source) 14 for irradiating a laser beam, which is a distance measuring light, is provided on the upper surface of the camera body 10 and directly above the taking lens 11. On the left side of the light emitting device 14, a release switch 15 and a liquid crystal display panel 16 are provided, and on the right side, a mode switching dial 17 and a V / D mode switching switch 18 are provided. A card insertion slot 19 for inserting a PC card is formed on a side surface of the camera body 10, and a video output terminal 20 and an interface connector 21 are 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, the CCD drive circuit 30, and the imaging signal processing circuit 33 are controlled by a system control circuit 35.

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.

The image signal read from the image memory 34 is sent to a TV signal encoder 38, and can be transmitted via a video output terminal 20 to a monitor device 39 provided outside the camera body 10. The system control circuit 35 is connected to the interface circuit 40, and the interface circuit 40 is connected to the interface connector 21.
It is connected to the. Therefore, the image signal read from the image memory 34 can be transmitted to the computer 41 connected to the interface connector 21. The system control circuit 35 includes a recording medium control circuit 42
Is connected to the image recording device 43 via the. Therefore, the image signal read from the image memory 34 can be recorded on a recording medium M such as an IC memory card mounted on the image recording device 43.

A light emitting element control circuit 44 is connected to the system control circuit 35. The light emitting device 14 is provided with a light emitting element 14a and an illumination lens 14b, and the light emitting operation of the light emitting element 14a is controlled by a light emitting element control circuit 44. The light emitting element 14a irradiates a laser beam as a distance measuring beam, and this laser beam is radiated to an object to be measured via an illumination lens 14b. Light reflected from the object to be measured enters the photographing lens 11. This light is transferred to the CCD
The detection by 28 measures a three-dimensional image of the measured object as described later.

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 46.

Referring to FIGS. 3 and 4, the principle of distance measurement in the present embodiment will be described. In FIG. 4, the horizontal axis is time t.

The distance measuring light output from the distance measuring device B is reflected by the measured object S and received by a CCD (not shown). The distance measuring light is a pulsed light having a predetermined pulse width H. Therefore, the reflected light from the measured object 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 distance measuring light and the reflected light have traveled twice the distance r between the distance measuring device T and the measured object S, the distance r is r = δ · t · C / 2 (1) ). 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 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 the present embodiment, utilizing the above-described principle,
The distance from the camera body 10 to each point on the surface of the object S to be measured is detected by detecting the amount of received light A at each of a plurality of photodiodes (photoelectric conversion elements) provided on the CCD 28 and arranged two-dimensionally. The data of the three-dimensional image relating to the surface shape of the measured object S is detected and input at a time.

FIG. 5 is a diagram showing the arrangement of the photodiode 51 and the vertical transfer unit 52 provided on the CCD 28.
FIG. 6 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 (signal charge holding 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 (vertical direction in FIG. 5). The vertical transfer unit 52 includes four vertical transfer electrodes 52 a and 52 for one photodiode 51.
b, 52c and 52d. 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 is conventionally known. The number of vertical transfer electrodes can be freely changed according to the purpose.

The 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, a charge corresponding to the amount of incident light (reflected light from the measured object) is 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 discharged to the substrate 53 side by the charge discharge signal, the photodiode 5
The so-called electronic shutter operation is realized by transferring the signal charges accumulated in 1 to the vertical transfer unit 52 side by a charge transfer signal.

FIG. 7 is a timing chart of a distance information detecting operation for detecting data relating to the distance to each point on the surface of the measured object. The operation of detecting distance information will be described with reference to FIGS.

An electric charge sweeping signal (pulse signal) S2 is output in synchronization with the output of the vertical synchronizing signal S1, whereby unnecessary charges accumulated in the photodiode 51 are removed from the substrate 53.
In the direction of The light emitting device 14 is activated simultaneously with the end of the output of the charge sweeping signal S2, and the pulse-shaped ranging light S3 having a constant pulse width is output. The distance measuring light S3 is reflected by the object to be measured and enters the CCD 28. That is, the reflected light S4 from the object to be measured by the CCD 28
Is received. When a certain time has elapsed from the output of the distance measuring light S3, a charge transfer signal (pulse signal) S5 is output,
Thereby, the charges accumulated in the photodiode 51 are transferred to the vertical transfer unit 52. The output of the charge transfer signal S5 is performed before the end of the output of the ranging light.

As described above, during the period T _U1 from the end of the output of the charge sweep signal S2 to the start of the output of the charge transfer signal S5, signal charges corresponding to the distance to the object to be measured are accumulated in the photodiode 51. You. That is, the distance measuring light S3
Although but the period T _S and the charge accumulation period T _U1 output is started at the same time, completed faster towards the charge accumulation period T _U1, reflected light S
4 is detected by the CCD 28, and the signal charge S6 generated by the detected light corresponds to the distance to the measured object. In other words, of the reflected light S4 from the measured object, the signal charge S6 corresponding to the light that has reached the photodiode 51 during the charge storage period _TU1 is stored in the photodiode 51. This signal charge S6 is transferred to the vertical transfer unit 52 by the charge transfer signal S5. Note that the output period T _S of the distance measurement light S3 may start earlier than the charge accumulation period T _U1 .

After a predetermined time has passed from the output of the charge transfer signal S5, the charge sweeping signal S2 is output again, and after the transfer of the signal charge to the vertical transfer section 52, the photodiode 51
Unnecessary charges accumulated in the substrate 53 are swept toward the substrate 53.
That is, accumulation of signal charges in the photodiode 51 is newly started. Then, as described above, when the charge accumulation period T _U1 has elapsed, the signal charge is transferred to the vertical transfer unit 52.

The vertical transfer section 53 of such signal charges S6
Is repeatedly executed until the next vertical synchronization signal S1 is output. As a result, in the vertical transfer unit 52, the signal charge S6 is integrated, and in the signal charge S6 integrated during the period of one field (the period sandwiched between the two vertical synchronization signals S1), the measured object is stationary during that period. If it can be considered, it corresponds to the distance information to the measured object.

The operation of detecting the signal charge S6 described above is 1
One of the photodiodes 51 performs such a detection operation in all the photodiodes 51. As a result of the detection operation in one field period, the distance information detected by the photodiode 51 is held in each part of the vertical transfer unit 52 adjacent to each photodiode 51. This distance information is output from the CCD 28 by the vertical transfer operation in the vertical transfer unit 52 and the horizontal transfer operation in the horizontal transfer unit (not shown), and is taken out of the three-dimensional image input device as three-dimensional image data of the measured object.

FIG. 8 is a flowchart of a program for executing a distance information detecting operation and a two-dimensional image photographing operation. These operations will be described with reference to FIGS. 1, 2, 5, 7, and 8.

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, in step 103, the vertical synchronizing signal S1 is output and the ranging light control is started. That is, the light emitting device 14 is driven, and the pulse-shaped ranging light S3 is output intermittently. Next, step 104 is executed, and the detection control by the CCD 28 is started. That is, the distance information detection operation is started, the charge sweeping signal S2 and the charge transfer signal S5 are alternately output, and the signal charge S6 of the distance information is integrated in the vertical transfer unit 52.

In step 105, 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 S1 has been output. When one field period ends, the routine proceeds to step 106, where the signal charge S6 of the distance information is output from the CCD. This signal charge S6 is temporarily stored in the image memory 34 in step 107. In step 108, 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 109, steps 103 to 1
08 Distance measurement using the distance information obtained in (D)
Data processing is performed, and in step 110, D data is output, and this program ends.

On the other hand, when it is determined in step 102 that the V mode has been selected, in step 111, the distance measuring light control is switched to the off state. That is, V
In the mode, irradiation of distance measuring light is prohibited. Step 112
Then, the normal photographing operation (CCD video control) by the CCD 28 is set to the ON state, a two-dimensional image is photographed, and the program ends.

As described above, according to the present embodiment, the distance information detecting operation for measuring the three-dimensional shape of the measured object and the photographing operation of the two-dimensional image of the measured object can be selectively executed. . Since the emission of distance measuring light (infrared laser light) is prohibited during the photographing operation, power consumption can be suppressed.

Further, according to the present embodiment, since no optical shutter is required, the three-dimensional image input device can be reduced in size and can be manufactured at low cost. In addition, the present embodiment is configured to output a large number of charge sweeping signals (pulse signals) to measure the distance to the object to be measured once and integrate the signal charge S6, so that a sufficiently large output is obtained. Can be obtained.

Further, according to the present embodiment, it is possible to collectively measure the data of the three-dimensional image relating to the surface shape of the measured object, that is, the distance information, without scanning the measured object with the distance measuring light. it can. Therefore, it is possible to greatly reduce the time required to obtain a three-dimensional image of the measured object.

[0040]

As described above, according to the present invention, it is possible to detect a three-dimensional shape of a measured object and to capture a two-dimensional image, and to reduce power consumption as much as possible. Is obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a camera provided with an image input 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 for explaining the principle of distance measurement using ranging light.

FIG. 4 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. 5 is a diagram showing an arrangement of a photodiode and a vertical transfer unit provided in a CCD.

FIG. 6 is a cross-sectional view of the CCD cut along a plane perpendicular to the substrate.

FIG. 7 is a timing chart of a distance information detecting operation for detecting data relating to a distance to an object to be measured.

FIG. 8 is a flowchart of a program for executing a distance information detecting operation and a two-dimensional image photographing operation.

[Explanation of symbols]

 10 Camera body 14 Light emitting device 15 Release switch S Object to be measured

Claims (9)

[Claims] A distance measuring unit that irradiates a distance measurement light to the object to be measured and detects a reflected light from the object to be measured to measure a distance to the object to be measured; An image input apparatus comprising: a photographing unit that photographs a two-dimensional image of a measurement object; and a control unit that can selectively drive one of the distance measuring unit and the photographing unit. 2. The image input apparatus according to claim 1, wherein the control unit prohibits the irradiation of the distance measuring light when driving the photographing unit. 3. A light source for irradiating the object to be measured with distance measuring light, and a plurality of photoelectric conversion elements receiving reflected light from the object to be measured and accumulating charges corresponding to the amount of received light. And a signal charge holding unit provided adjacent to the photoelectric conversion element, and a signal in the photoelectric conversion element by sweeping unnecessary charges accumulated in the photoelectric conversion element from the photoelectric conversion element and stopping the operation. A stored charge sweeping means for starting a charge storage operation; a signal charge transferring means for transferring the signal charge stored in the photoelectric conversion element to the signal charge holding unit; a storage charge sweeping means and the signal charge transferring means 2. The image input device according to claim 1, further comprising: signal charge integration means for integrating the signal charge in the signal charge holding unit by alternately driving the signal charge. 4. The photoelectric conversion element is of a charge storage type,
The image input device according to claim 3, wherein the image input device is arranged two-dimensionally. 5. The image input device according to claim 4, wherein said photoelectric conversion element is formed along a substrate, and said accumulated charge sweeping means sweeps out unnecessary charges toward said substrate. 6. The signal charge holding section reduces the signal charge by three.
The image input device according to claim 3, wherein the image input device is a vertical transfer unit for outputting to the outside of the three-dimensional image input device. 7. The photoelectric conversion element and a signal charge holding unit,
Interline CC with vertical overflow drain structure
The image input device according to claim 3, wherein the image input device is configured as D. 8. A charge sweeping signal output by the accumulated charge sweeping means and sweeping out the unnecessary charge, and a charge transfer signal output by the signal charge transferring means and transferring the signal charge. The image input device according to claim 3, wherein each of the image input devices is a pulse signal. 9. A first charge accumulation period from when the light source outputs pulse-shaped ranging light having a predetermined pulse width and when the charge sweep signal is output until the charge transfer signal is output. 9. The image input device according to claim 8, wherein the signal charge corresponding to the distance information is integrated in the signal charge holding unit by outputting the pulse of the distance measuring light.