JPH06268929A - Light projection image pickup device - Google Patents

Abstract

PURPOSE:To extract a picture of a lighted part without being affected by an external light even from a fast moving object by using a conventional CCD. CONSTITUTION:A light projection section 1 emits a pulse light to an object of image pickup repetitively and an optical section 2 receives an optical picture from the object and divides it into two, the one picture is received by a 1st photoelectric conversion section 3 so as to be in opposite phase to the light, in which the light is converted into a picture signal and the other picture is received by a 2nd photoelectric conversion section 4 so as to be in phase to the light, in which the light is converted into a picture signal and a control processing section 5 calculates the difference picture to extract a picture of the lighted part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light projection image pickup device used as an optical cutting machine, a three-dimensional distance measuring device, an object recognition device mounted on an automobile or the like.

[0002]

2. Description of the Related Art As an image pickup apparatus such as a television camera, the apparatus shown in FIG. 7 is conventionally known.

In this image pickup apparatus, an optical image of a subject to be picked up is captured by a lens 102 and condensed, and a shutter controller circuit 103 sets an electronic shutter 104 at a rate of once per frame.
From about / 5000 seconds to about 1/100 seconds, the optical image focused by the lens 102 is turned on (transmission state) and is incident on the CCD 105 to be converted into an electric image (two-dimensional image signal).

2 stored in the CCD 105 by the CCD control / video signal processing circuit 106.
A three-dimensional image signal is serially read and this is output as a video signal.

[0005]

By the way, in such an image pickup apparatus, since the optical image from the outside is condensed on the CCD 105 by the lens 102, the light from the object to be imaged is not emitted. When it is weak, a light-transmitting device is added to the image pickup device shown in FIG. 7 to form a light-emission image pickup device. While the light-emitter of the light-emission image pickup device illuminates an object to be imaged, the reflected light is taken in to obtain a video signal. To generate.

In this case, in a light projector and a three-dimensional distance measuring device, a light projection image pickup device used as a device for illuminating light to read characters and recognizing an object, a laser slit light is emitted by a light projector. Or a laser spot light is radiated to the object, and the reflected light from the object is condensed by the lens, and is incident on the CCD for a required time by the electronic shutter to form a video signal, and then the CCD control / video signal processing circuit The portion illuminated by the laser slit light or laser spot light is extracted by image processing.

However, in such a floodlight imaging device, when the object to be imaged is irradiated with external light (for example, sunlight) stronger than the laser slit light or the laser spot light, the laser slit light or the laser slit light is emitted. There is a problem that it is difficult to extract the image of the part where the is irradiated.

Therefore, as one of methods for solving such a problem, Japanese Patent Laid-Open No. 2-304680 has been conventionally proposed.

In this proposal, a projector and a television camera constitute a projection image pickup device, and before emitting light from the projector, an image is captured by the television camera and stored in a memory as an unprojected image. After that, while emitting light from the projector, an image is captured by the television camera and stored as a projected image in a memory different from the memory.

Then, the unprojected image and the projected image stored in each of these memories are read out, the difference between them is calculated, the influence of external light is removed, and the difference obtained by this processing is calculated. The image is extracted as an image of the projected portion.

However, in such a light-projecting image pickup device, only a video signal can be output from the television camera at a cycle of 1/30 second, so that two images are captured and the difference between these images is captured. It takes 2/30 seconds to extract the image.

Therefore, in such a projection image pickup device,
Although it is possible to capture a still object (subject) and extract the image of the projected part, two images are displayed when the subject is moving fast, such as a road or an oncoming vehicle viewed from above the automobile. There is a problem that it becomes impossible to extract the image of the projected portion as images of different subjects.

Therefore, in order to solve such a problem,
Since a fast-moving subject is photographed, it is conceivable to shorten the image input cycle.

That is, in a normal television camera,
It takes 16.6 ms to input an image in one field, and takes 33.3 ms to input an image in one frame composed of images in two fields. To input 33.3m
It takes s time, and it takes a total of 66.6 ms to obtain one difference image. However, this is shortened to about 1 ms for each fast moving object.
It is conceivable to extract the image of the projected portion.

However, such a method requires a very expensive device such as a high-speed camera capable of picking up images at a high speed as a television camera, so that the cost is too high and it is difficult to realize. There is.

In view of the above circumstances, the present invention is a conventional CCD.
It is an object of the present invention to provide a floodlight imaging device capable of extracting an image of an illuminated portion without being affected by extraneous light by using a fast moving object.

[0017]

In order to achieve the above object, a projection image pickup device according to the present invention comprises a light projecting section for repeatedly emitting light to illuminate a subject within one frame period, and an optical system for the subject. An optical part that captures an image and divides it into multiple parts,
When light is emitted from the light projecting unit, a first optical / electrical converting unit that takes in one optical image divided by the optical unit and generates an image signal, and the first optical / electrical converting unit Immediately before or after the optical / electrical conversion period, when light is not emitted from the light projecting unit, a second optical / electrical conversion unit that captures another optical image divided by the optical unit to generate an image signal And a control / processing unit that calculates a difference image between the image signal output from the second photoelectric conversion unit and the image signal output from the first photoelectric conversion unit to generate a video signal. It is characterized by having.

[0018]

In the above structure, the light projecting unit repeatedly generates light within one frame period to illuminate the subject, while the optical unit captures the optical image of the subject and divides it into a plurality of images. When light is emitted from the optical section, the first optical / electrical conversion section captures one optical image divided by the optical section to generate an image signal, and the light of the first optical / electrical conversion section is generated. / Immediately before or after the electrical / electrical conversion period, when no light is emitted from the light projecting unit, another optical image divided by the optical unit is captured by the second optical / electrical converting unit to generate an image signal. After that, the control / processing unit calculates a difference image between the image signal output from the second photoelectric conversion unit and the image signal output from the first photoelectric conversion unit to generate a video signal. To be done.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing an embodiment of a floodlight imaging device according to the present invention.

The projection image pickup apparatus shown in this figure is provided with a projection unit 1.
, The optical section 2, the two photoelectric conversion sections 3, 4, and
The processing unit 5 is provided, and the reflected light (optical image) from the subject is captured so as to be in-phase and anti-phase with the light while repeating the operation of irradiating the subject to be imaged with pulsed light. After being converted into an image signal by, the difference image is calculated to extract the image of the illuminated portion.

As shown in FIG. 2 (c), the light projecting unit 1 supplies a laser light source, an LED, a discharge lamp while the light emitting signal is supplied every time the light emitting signal is output from the control / processing unit 5. The light emitting body 6 such as a strobe light source is caused to emit light, and the light obtained by the light emitting body 6 is collimated by the lens 7 to illuminate the subject.

Further, the optical unit 2 takes in the reflected light (optical image) from the subject by the lens 10 and condenses it, and the spectral prism 11 divides the optical image into two optical images and divides the two into one. Is incident on the photoelectric conversion unit 3, and the other is incident on the photoelectric conversion unit 4.

One photoelectric conversion unit 3 outputs a shutter-on signal having a phase opposite to the output timing of the light emission signal from the control / processing unit 5 as shown in FIG. 2 (a).
While this shutter-on signal is being supplied (for example, 1
/ 1000 seconds to 1/10000 seconds), electronic shutter 12 composed of PLZT, liquid crystal shutter, etc.
One of the optical images separated by the optical unit 2 is transmitted and made incident on the CCD 13, whereby the optical image is photoelectrically converted to accumulate a two-dimensional image signal.
As shown in (d), when the control / processing unit 5 outputs a read timing signal corresponding to a vertical synchronizing signal having a cycle of 30 Hz, the image signal accumulated from the CCD 13 is serially output to control / processing unit. Supply to 5.

The other optical / electrical conversion section 4 is shown in FIG.
As shown in (b), every time the control / processing unit 5 outputs a shutter-on signal that is in phase with the output timing of the light emission signal, while the shutter-on signal is being supplied,
The other optical image separated by the optical unit 2 by the electronic shutter 14 is transmitted and made incident on the CCD 15, whereby the optical image is photoelectrically converted to accumulate a two-dimensional image signal. When a read timing signal corresponding to the vertical synchronizing signal is output from the control / processing unit 5 as shown in (4), the image signal accumulated from the CCD 15 is serially output and supplied to the control / processing unit 5.

In this case, each of these optical / electrical conversion units 3, 4 is
Each of the CCDs 13 and 15 constituting the CCD is a normal CCD in which the charge increases for each pixel according to the light supply amount, as shown in FIG.
Therefore, after the electric charge becomes zero due to the previous reading process (for example, at time t0) and before the end of the current frame, with a strong light amount according to the light amount of the incident optical image,
As indicated by the solid line, or when the amount of light is weak, the charge increases as indicated by the dotted line, and when the reading process is performed (for example, time t1), from this time until the next frame starts (for example, time t2). , The charge is kept at zero.

Therefore, as shown in FIGS. 4C and 4E, the CCD 13 provided in one photoelectric conversion unit 3 outputs a shutter-on signal having a phase opposite to the output timing of the light emission signal. Each time, the optical image is incident,
As shown in Fig. 4 (a), the electric charge increases each time
When the read timing signal is output from the processing unit 5 (for example, at time t1), the charge of each pixel is serially output and becomes zero, and in the CCD 15 provided in the other photoelectric conversion unit 4, As shown in FIGS. 4D and 4E, the optical image is incident each time the shutter-on signal that is in phase with the output timing of the light emission signal is output.
As shown in (b), the charge increases each time, and when the read timing signal is output from the control / processing unit 5 (for example, time t1), the charge of each pixel is serially output and becomes zero.

By this, each of these CCDs 13, 1
If the duty of the optical image incident on the optical axis 5 is set to 50%, it is possible to output an image signal of about half the level of a normal imaging operation in which the optical image is continuously incident for one frame, and to emit light. One of the electronic shutters 12 is set in a transparent state by a shutter-on signal having a phase opposite to the signal output timing, and the other electronic shutter 14 is set in a transparent state by a shutter-on signal having the same phase as the shutter-on signal. Since the ON / OFF cycle of each of these shutter-on signals is set earlier, it is possible to make the optical images of substantially the same part of the subject enter the CCDs 13 and 15 even when the subject moves fast.

Further, the control / processing section 5 generates a light emission signal at a preset timing by the shutter controller circuit 18 and supplies the light emission signal to the light projecting section 1, and at the same time, the shutter is turned on in a phase opposite to the light emission signal. Signal, a shutter-on signal having the same phase is generated and supplied to the electronic shutters 12 and 14 of the photoelectric conversion units 3 and 4, respectively, while the CCD controller circuit 16 reads out timing corresponding to the vertical synchronizing signal. Each optical / electrical conversion unit 3,
Each of the four CCDs 13 and 15 is controlled to output an image signal, a video signal processing circuit 17 extracts these difference images, and this is output as a video signal.

In this case, the video signal processing circuit 17 operates as shown in FIG.
As shown in FIG.
The difference image between the image signal output from the CCD 15 and the image signal output from the other CCD 15 is extracted and output as a video signal.

As described above, in this embodiment, while the operation of irradiating the object to be imaged with light in a pulsed manner is repeated, the reflected light (optical image) from the object becomes in-phase and anti-phase with the light. ) Is taken in and converted into an image signal, the difference image is calculated to extract the image of the illuminated part. It is possible to extract the image of the illuminated portion without being affected by.

FIG. 6 is a block diagram showing another embodiment of the floodlight imaging device according to the present invention. In addition, in this figure,
The same parts as those in FIG. 1 are designated by the same reference numerals.

The projection image pickup apparatus shown in this figure differs from the apparatus shown in FIG. 1 in that the video signal output from the video signal processing circuit 17 by the integrator circuit 25 is set in units of one image (3
The shutter controller circuit 1 based on the signal level of the averaged image signal obtained by the averaging process by the phase shift circuit 26 configured by a microprocessor or the like.
The light emission signal output from 8 and the pulse position of each shutter-on signal are output from the integration processing circuit 25 within one cycle, with the pulse interval kept constant, the timing being advanced or delayed. This is to automatically detect the timing when the signal level of the averaged image signal becomes maximum.

As a result, in this embodiment, for example, when the projection image pickup device is mounted on an automobile, the two automobiles run in parallel and the lights emitted by these automobiles are in a phase opposite to each other. Even so, the value of the video signal output from the video signal processing circuit 17 can be prevented from becoming zero.

Further, in this embodiment, the integrating circuit 25 is provided on the output side of the video signal processing circuit 17, and
Although the phase shift circuit 26 is provided on the output side of the integrating circuit 25, the phase shift circuit 26 is provided in the video signal processing circuit 17 used in the projection image pickup apparatus shown in FIG. 1, that is, in the video signal processing circuit 15 shown in FIG. The absolute value calculating circuit is provided after the differential amplifying circuit 19, and the absolute value calculating circuit full-wave rectifies the video signal output from the differential amplifying circuit 19 to obtain the absolute value. May be output as.

By doing so, the light / electric conversion unit 4 which is in phase when light is projected by the strong light of another vehicle while the phase is opposite to the light projection timing of the own vehicle. The image signal output from the opto-electric conversion unit 3 having the opposite phase is larger than the image signal output from, and the video signal output from the differential amplifier circuit 19 shown in FIG. However, it is possible to obtain the same effect as that of the other embodiments described above by making this a positive polarity by the absolute value calculation circuit.

Further, in each of the above-described embodiments, the shutter controller circuit 18 generates a pulsed light emission signal or each shutter-on signal to drive the light emitter 6 and each electronic shutter 12, 14. Generates a sine wave light emission signal and each shutter-on signal,
Alternatively, the electronic shutters 12 and 14 may be driven.

When the projection image pickup device shown in each of the above-mentioned embodiments is used as an optical cutting machine for measuring the height of an object, a laser slit light can be generated as the light emitter 6. Can be made unaffected by external light.

Further, when the projection image pickup device shown in each of the above-mentioned embodiments is used as a visual device of an automobile, by using a light emitting body such as a discharge lamp or a light emitting body which emits laser light It is possible to obtain a video signal that is not affected, and it is possible to detect the white line, eliminate the shadow that was generated when the weather was fine, and display the front image even when the backlight is generated when the sun is in the traveling direction. It is possible to obtain a clear image even at night.

[0039]

As described above, according to the present invention, a normal CCD can be used to extract an image of an illuminated portion of a fast-moving subject without being affected by external light. it can.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a floodlight imaging device according to the present invention.

FIG. 2 is a timing chart showing an example of a relationship between an on / off operation of each electronic shutter shown in FIG. 1, an on / off operation of a light emitter, and a read operation of each CCD.

FIG. 3 is a schematic diagram showing an example of a basic relationship between the amount of incident light of each CCD shown in FIG. 1 and accumulated charges.

FIG. 4 is a waveform chart showing an example of a relationship between a light emitting operation of the light emitting body shown in FIG. 1, an on / off operation of each electronic shutter, and an amount of electric charge actually accumulated in each CCD.

5 is a circuit diagram showing a detailed circuit configuration example of the video signal processing circuit shown in FIG.

FIG. 6 is a block diagram showing another embodiment of the floodlight imaging device according to the present invention.

FIG. 7 is a block diagram showing an example of a conventionally known imaging device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light projecting section 2 Optical section 3, 4 Optical / electrical converting section 5 Control / processing section 6 Light emitting body 7, 10 Lens 11 Spectral prism 12, 14 Electronic shutter 13, 15 CCD 16 CCD controller circuit 17 Video signal processing circuit 18 Shutter controller circuit

Claims (1)

[Claims] 1. A light projecting unit that repeatedly emits light within one frame period to irradiate a subject with light, an optical unit that captures an optical image of the subject and divides it into a plurality, and light is emitted from the light projecting unit. When the optical / electrical conversion section of the first optical / electrical conversion section receives the one optical image divided by the optical section and generates an image signal, the optical / electrical conversion section of the first optical / electrical conversion section is provided immediately before or after the optical / electrical conversion period. A second optical / electrical conversion unit that captures another optical image divided by the optical unit and generates an image signal when no light is emitted from the light projecting unit; And a control / processing unit that generates a video signal by calculating a difference image between the image signal output from the first optical / electrical conversion unit and the image signal output from the first optical / electrical conversion unit. Imaging device.