Scanning type image pick-up apparatus and a scanning type laser beam receive apparatus

The present invention has an object of realizing highly reliable search with high precision by obtaining a clear view image over a wide view. In particular, a reflection mirror is formed so as to correspond to an image pick-up element at a focus surface of a converging lens of an image pick-up camera and the image pick-up camera is arranged to be capable of freely performing scanning by a scanning mechanism portion. As a result, with the image pick-up camera kept performing linear scanning, the reflection mirror performs triangular scanning in a direction opposite to the scanning direction of the image pick-up camera for every frame cycle T and a light wave taken in by the converging lens is introduced to the image pick-up element for every one frame, thereby to obtain a static view image. The desired object is thus achieved.

BACKGROUND OF THE INVENTION

The present invention relates to a scanning type image pick-up apparatus and a scanning type laser beam receive apparatus suitable for passively or actively scanning a wide view-field by a two-dimensional manner.

In general, in this kind of scanning type image pick-up apparatus, an image pick-up camera internally including an image pick-up element of a charge storing type is used to obtain a light wave. In this image pick-up camera, the image pick-up element has a view angle θ and therefore, a method of scanning a search range to take in the view image is adopted in case of searching a wide view.

In the image pick-up camera as described above, the image pick-up element is provided at a focus position of an optical system, and image data is obtained by taking in light waves of a visible region (e.g., 0.4 μm to 0.8 μm) and an infrared region (e.g., 3 μm to 12 μm) received by the optical system and performing photoelectric conversion thereon. Therefore, if an angle range equivalent to an instant view angle of one pixel of the image pick-up element is scanned in one direction at a speed faster than the speed at which the image pick-up element is exposed, a so-called image flow is caused and the view image obtained thereby becomes unclear.

Therefore, a conventional scanning type image pick-up apparatus adopts a reflection mirror step scanning method in which a reflection mirror is provided before an image pick-up camera and the reflection mirror is scanned in steps for every unit angle equivalent to a view angle in synchronism with the frame time of the image pick-up element, thereby to pick up light waves into an image pick-up element within one frame time (or exposure time) and to obtain a view image, or a camera step scanning method in which an image pick-up camera directly performs scanning in steps, thereby to pick up light waves into an image pick-up element within one frame time (or exposure time) and to obtain a view image.

However, if the scanning type image pick-up apparatus as described above is constructed so as to have a wide view range, a large reflection mirror is required from the limitations of the focal distance and the image pick-up distance, in case of the former method, and an optical system such as a converging lens must be a large size, in case of the latter method. Thus, in both cases, the apparatus has a very heavy weight. Therefore, in any of these methods, a large driving force is required for step scanning, and a time delay occurs when scanning is started, so that it is difficult to obtain stable view images.

For example, since a reflection mirror or an image pick-up camera has a large size and a heavy weight, it is very difficult to perform step scanning with a high speed of about an image pick-up element frame frequency 60 Hz and a frame cycle 16.7 ms, and therefore, a problem occurs in that a clear image is difficult to obtain. The same problem occurs in case of a scanning type laser beam receive apparatus.

BRIEF SUMMARY OF THE INVENTION

As has been explained above, a conventional scanning type image pick-up apparatus has a problem in that it is difficult to obtain a clear view image when search over a wide view is realized.

The present invention has been made in view of the above situation, and has an object of providing a scanning type image pick-up apparatus and a laser beam receive apparatus which obtain a clear view image over a wide view to realize highly reliable search with high precision.

A scanning type image pick-up apparatus comprising: an image pick-up camera for converging a light wave by a first optical system, changing an optical path of the light wave by a second optical system, and taking in the light wave into a charge storage type image pick-up element, thereby to obtain a view image, the second optical system being arranged to be capable of freely performing scanning on the image pick-up element with the light wave from the first optical system; camera scanning means for causing the image pick-up camera to linearly scan a view range, thereby to take in the light wave into the first optical system; and first optical system scanning means for causing the second optical system of the image pick-up camera to perform triangular scanning in a direction opposite to a scanning direction of the image pick-up camera for every frame cycle of the image pick-up camera, thereby to introduce the light wave converged by the first optical system into the image pick-up element.

A scanning type image pick-up apparatus comprising: an image pick-up camera for converging a light wave by a first optical system, changing an optical path of the light wave by a second optical system, and taking in the light wave into a charge storage type image pick-up element, thereby to obtain a view image, the second optical system being arranged to be capable of freely performing scanning so as to correspond to the first optical system and the image pick-up element; camera scanning means for causing the image pick-up camera to linearly scan a view range, thereby to take in the light wave into the first optical system; and a rotation mechanism for rotating the second optical system of the image pick-up camera around an optical axis by an angle decided by scanning angle speeds in two axial directions of the two-dimensional scanning means and around an axis parallel to an incidence surface of the image pick-up element at an angle speed decided by scanning angle speeds in the two axial directions of the two-dimensional scanning means.

In addition, a scanning type laser beam receive apparatus comprising: a laser radar for converging a laser beam by a first optical system, for changing an optical path of the laser beam by a second optical system, and for taking in the laser beam into a laser beam receiver, thereby to obtain a view image, the second optical system being arranged to be capable of freely performing scanning so as to correspond to the first optical system and the laser beam receiver; and two-dimensional scanning means for causing the laser radar to linearly scan a view range, thereby to take in the laser beam into the first optical system, characterized in that the second optical system of the laser radar includes a mechanism which rotates the second optical system around an optical axis by an angle decided by scanning angle speed in two axial directions of the two-dimensional scanning means and around an axis parallel to a light receive surface of the laser beam receiver at an angle speed decided by scanning angle speeds in the two axial directions of the two-dimensional scanning means.

Another scanning type image pick-up apparatus characterized by comprising: an image pick-up camera for converging a light wave by a first optical system, for changing an optical path of the light wave by a second optical system, and for taking in the light wave into a charge storage type image pick-up element, thereby to obtain a view image, the second optical system being arranged to be capable of freely performing scanning with use of an electro-optical deflector capable of electrically deflecting the light wave so as to correspond to the first optical system and the image pick-up element; scanning means for causing the image pick-up camera to linearly scan a view range, thereby to take in the light wave into the first optical system; and deflector drive means for causing the electro-optical deflector to deflect an optical axis at an angle decided by a scanning angle speed of the scanning means.

Or, another scanning type image pick-up apparatus characterized by comprising: an image pick-up camera for converging a light wave by a first optical system, for changing an optical path of the light wave by a second optical system, and for taking in the light wave into a charge storage type image pick-up element, thereby to obtain a view image, the second optical system being arranged to be capable of freely performing scanning in a two-dimensional direction with use of first and second electro-optical deflectors respectively capable of electrically deflecting the light wave in directions perpendicular to each other so as to correspond to the first optical system and the image pick-up element; two-dimensional scanning means for causing the image pick-up camera to linearly scan a view range, thereby to take in the light wave into the first optical system; first deflector drive means for causing the first electro-optical deflector to deflect an optical axis at an angle decided by a scanning angle speed of the two-dimensional scanning means in a first axial direction thereof; and second deflector drive means for causing the second electro-optical deflector to deflect an optical axis at an angle decided by a scanning angle speed of the two-dimensional scanning means in a second axial direction thereof perpendicular to the first axial direction.

Or, another scanning type image pick-up apparatus characterized by comprising: an image pick-up camera for converging a light wave by a first optical system, for changing an optical path of the light wave by a second optical system, and for taking in the light wave into a charge storage type image pick-up element, thereby to obtain a view image, the second optical system being arranged to be capable of freely performing scanning in a two-dimensional direction with use of an electro-optical deflector capable of electrically deflecting the light wave so as to correspond to the first optical system and the image pick-up element and with use of a rotation mechanism for rotating the electro-optical deflector around an optical axis; two-dimensional scanning means for causing the image pickup camera to linearly scan a view range, thereby to take in the light wave into the first optical system; and deflector drive means for rotating the electro-optical deflector around an optical axis by an angle decided by scanning angle speeds of the two-dimensional scanning means in two axial directions thereof, with respect to the rotation mechanism of the image pick-up camera, and for causing the electro-optical deflector to deflect an optical axis around an axis parallel to a surface of the image pick-up element at an angle speed decided by the scanning angle speeds of the two-dimensional scanning means in the two axial directions thereof.

Another scanning type laser beam receive apparatus characterized by comprising: a laser radar for converging a laser beam by a first optical system, for changing an optical path of the laser beam by a second optical system, and for taking in the laser beam into a laser beam receiver, thereby to obtain a view image, the second optical system being arranged to be capable of freely performing scanning with use of an electro-optical deflector capable of electrically deflecting the laser beam so as to correspond to the first optical system and the laser beam receiver; scanning means for causing the laser radar to linearly scan a view range, thereby to take in the laser beam into the first optical system; and deflector drive means for causing the electro-optical deflector to deflect an optical axis at an angle decided by a scanning angle speed of the scanning means.

Or, another scanning type laser beam receive apparatus characterized by comprising: a laser radar for converging a laser beam by a first optical system, for changing an optical path of the laser beam by a second optical system, and for taking in the laser beam into a laser beam receiver, thereby to obtain a view image, the second optical system being arranged to be capable of freely performing scanning in a two-dimensional direction with use of first and second electro-optical deflectors respectively capable of electrically deflecting the laser beam in directions perpendicular to each other so as to correspond to the first optical system and the laser beam receiver; two-dimensional scanning means for causing the laser radar to linearly scan a view range, thereby to take in the laser beam into the first optical system; first deflector drive means for causing the first electro-optical deflector to deflect an optical axis at an angle decided by a scanning angle speed of the two-dimensional scanning means in a first axial direction thereof; and second deflector drive means for causing the second electro-optical deflector to deflect an optical axis at an angle decided by a scanning angle speed of the two-dimensional scanning means in a second axial direction thereof perpendicular to the first axial direction.

Or another scanning type laser beam receive apparatus characterized by comprising: a laser radar for converging a light wave by a first optical system, for changing an optical path of the laser beam by a second optical system, and for taking in the laser beam into a laser beam receiver, thereby to obtain a view image, the second optical system being arranged to be capable of freely performing scanning in a two-dimensional direction with use of an electro-optical deflector capable of electrically deflecting the laser beam so as to correspond to the first optical system and the laser beam receiver and with use of a rotation mechanism for rotating the electro-optical deflector around an optical axis; two-dimensional scanning means for causing the laser radar to linearly scan a view range, thereby to take in the laser beam into the first optical system; and deflector drive means for rotating the electro-optical deflector around an optical axis by an angle decided by scanning angle speeds of the two-dimensional scanning means in two axial directions thereof, with respect to the rotation mechanism of the laser radar, and for causing the electro-optical deflector to deflect an optical axis around an axis parallel to a surface of the laser radar at an angle speed decided by the scanning angle speeds of the two-dimensional scanning means in the two axial directions thereof.

DETAILED DESCRIPTION OF THE INVENTION

In the following, embodiments of the present invention will be explained with reference to the drawings.

Firstly, the basic structure of a scanning type image pick-up apparatus according to the present invention will be explained with reference toFIG. 1.

InFIG. 1, an image pick-up camera10for picking up light waves is mounted on a scanning mechanism portion11and is arranged to be capable of freely scanning one axial direction (e.g., azimuth direction) by the scanning mechanism portion11. The light waves are those included in a visible region described above (e.g., 0.4 μm to 0.8 μm) and an infrared region (e.g., 3 μm to 12 μm).

The scanning mechanism portion11described above comprises a torquer11aand a gimbal mechanism11b. The scanning mechanism portion11has an input end connected with an output end of an adder12through a servo amplifier13. The adder12has a minus input end connected with an output end of an angle sensor14and is inputted with a scanning angle signal of the scanning mechanism portion11through the angle sensor14. Further, the adder12has a plus input end connected with a camera scanning command signal output end of a scanning command signal generator portion15.

Specifically, the adder12generates a camera drive signal by obtaining a difference between a camera scanning command signal (i.e., a signal for instructing a scanning angle of an image pick-up camera10) outputted from the scanning command generator portion15and an actual scanning angle signal from an angle sensor14, and outputs the camera drive signal to the scanning mechanism portion11through the servo amplifier13. The scanning mechanism portion11controls the scanning angle φ the image pick-up camera10to be linear on the basis of the camera drive signal inputted (ref.FIG. 3).

The image pick-up camera10is constructed as a combination of a converging lens10a, a reflection mirror10b, and a charge storage type image pick-up element10chaving a view angle θ. A light wave picked up is converged by the converging lens10aand the light wave thus converged is imaged on the image pick-up element10cthrough the reflection mirror10b, thus obtaining a static view image.

Here, the reflection mirror10bis provided to be capable of freely performing triangular scanning in a camera scanning direction by a mirror scanning drive portion17in correspondence with the focusing surface of the converging lens10a, and the light wave converged by the converging lens10ais imaged on the image pick-up element10c. The reflection mirror10bis equipped with an angle sensor18, and an output end of the angle sensor18is connected with a minus input end of an adder19. A plus input end of the adder19is connected with a mirror scanning command signal output end of the scanning command signal generator portion15.

Specifically, the adder19generates a mirror drive signal by obtaining a difference between a mirror scanning command signal (or a signal for instructing a triangular scanning angle of the reflection mirror10b) from the scanning command signal generator portion15and an actual mirror angle signal from the angle sensor18, and outputs the mirror drive signal through a servo amplifier20to the mirror scanning mechanism portion17described above. The mirror scanning mechanism portion17causes the reflection mirror10bto perform triangular scanning or so-called swing scanning in the direction opposite to the camera scanning direction, on the basis of the mirror drive signal inputted (ref.FIG. 3B).

Here, a light wave enters into the image pick-up element10cat an incidence angle Δφ (ref.FIGS. 3C and 3D), and a desired view angle θ is maintained. Simultaneously, the image pick-up element10cis controlled by a synchronous trigger for every frame cycle T, and exposure of an optical image and charge reading operation are carried out (ref.FIGS. 3E and 3F), so that a static view image is obtained.

The scanning command signal generator portion15generates a camera scanning command signal for causing the image pick-up camera10to perform scanning and a mirror scanning command signal for causing the reflection mirror10bto perform scanning, on the basis of a command signal not shown, as described above.

In the structure as described above, for example, where the view angle θ is set to 3° and the frame frequency and the frame cycle are 60 Hz and T ( 1/60) s (1.67 ms), the scanning command signal generator portion15generates such a camera scanning command signal which causes the image pick-up camera10to scan one direction (e.g., the azimuth direction) at an angle speed of 3°/( 1/60)=180° and the portion15outputs the camera scanning command signal to the adder12. The adder obtains a difference between the camera scanning command signal and a camera angle signal from an angle sensor14, generates a camera drive signal, and controls and drives a scanning mechanism portion11through a servo amplifier13. In this manner, the image pick-up camera10is controlled so as to scan one direction (e.g., the azimuth direction) at an angle speed of 3°/( 1/60)=180° within a view, and light waves are picked up by a converging lens10a.

Simultaneously, the scanning command signal generator portion15generates a mirror scanning command signal which causes the reflection10bof the image pick-up camera10to perform triangular scanning in a direction opposite to the camera scanning direction at an angle speed of ½ of 180°/s in synchronism with a synchronous trigger of a frame cycle T of the image approximately for every 1/60 s (e.g., 16 ms), and outputs the mirror scanning command signal to the adder19. The adder obtains a difference between the scanning command signal and a mirror angle signal from the angle sensor18, to generate a mirror drive signal, and controls and drives the mirror scanning mechanism portion17through the servo amplifier20. In this manner, the reflection mirror10bperforms triangular scanning at an angle speed of ½ of 180° in the direction opposite to the camera scanning direction in synchronism with a synchronous trigger of a frame cycle T of the image pick-up element10capproximately for every 1/60 s (e.g., 16 ms), and light waves converged by the converging lens10aare introduced at an incidence angle Δφ, to form an image.

The image pick-up element10cmaintains a desired exposure time Ta so that a desired charge reading time Tb is maintained thereby to attain a static view image at a view angle θ.

In case of scanning a direction substantially perpendicular to the scanning direction on condition that the image pick-up camera10has completed scanning in one direction, for example, the image pick-up camera10together with the scanning mechanism portion11is caused to scan this direction and the image pick-up camera10and the reflection mirror10brepeat scanning in the same manner as described above, thereby to obtain a static view image. The time at which scanning is performed in the direction substantially perpendicular to the scanning direction is set within the charge reading time Tb.

Thus, the image pick-up apparatus described above is arranged such that the reflection mirror10bis formed on the focus plane of the converging lens10aof the image pick-up camera10so as to freely perform scanning in correspondence with the image pick-up element10cand such that the image pick-up camera10is arranged so as to freely perform scanning through the image pick-up element10c. In this manner, with the image pick-up camera10kept performing linear scanning, the reflection mirror10bis caused to perform triangular scanning in the direction opposite to the scanning direction of the image pick-up camera10for every frame cycle T of the image pick-up element10c, and light waves picked up by the converging lens10aare introduced into the image pick-up element10cfor every frame, thereby to obtain a static view image.

As a result, since only the reflection mirror10bhaving a relatively small size enough to take in an image formed on the focus plane of the converging lens10ainto the image pick-up element10cneeds to perform scanning in correspondence with the image pick-up camera10, secure operation control for obtaining image data can be easily realized within a view angle of the image pick-up element10c. Therefore, a clear precise static image can be securely obtained within a wide view picked up by the image pick-up camera10.

In addition, in this manner, as the sensitivity of the image pick-up element10cis raised to be high, it is possible to obtain a clear static view image which matches with such a high sensitivity. Therefore, sensitivity performance of the image pick-up element10ccan be effectively used.

Note that the above embodiment describes a case in which the image pick-up camera10is arranged so as to freely scan one axial direction with use of the scanning mechanism portion11. However, the scanning mechanism potion11may be constructed so as to scan two axial directions substantially perpendicular to each other, e.g., the azimuth direction and the elevation direction, and the image pick-up camera10itself may be constructed so as to scan two directions substantially perpendicular to each other.

Further, the above embodiment has been explained as a case in which the reflection mirror10bis provided in the image pick-up camera10so as to perform scanning freely and light waves converged by the converging lens10aare reflected by the reflection mirror10bso as to form an optical image on the image pick-up camera10. However, an optical phase member such as an optical phase shifter or the like which makes light waves passing and set in a phase may be provided on the focus plane of the converging lens10a, and light waves converged by the converging lens10amay be introduced to the image pick-up element10cthrough the optical phase member. In this case, substantially, the same effects as obtained in the above embodiment can be expected.

In the structure shown inFIG. 1, the rotation (or swing) shaft of the reflection mirror10bfor restricting an image flow must be set in parallel with one scanning axis of the entire image pick-up camera10, and therefore, operation of restricting an image flow cannot be performed in the other direction. For example, this means that the axis of the reflection mirror10bis set in parallel with one of two scanning axes when two axes of a horizontal direction and a vertical direction are adopted for search scanning, and the scanning direction vertical to the axis of the reflection mirror10bis the main scanning direction. For example, when search scanning is performed in an obliquely upward direction, horizontal components of an image flow can be restricted and vertical components of an image flow cannot be restricted. This is a main problem to be solved by the present invention.

FIG. 4shows a structure of a first embodiment of a scanning type image pick-up apparatus according to the present invention. Note that those components ofFIG. 4which are the same as those ofFIG. 1are referred to by the same reference symbols and only those components ofFIG. 4which are different from those ofFIG. 1will now be described in detail below.

InFIG. 4, an image pick-up camera10is mounted on a scanning mechanism portion11and is caused to scan an arbitrary direction decided by synthesizing two-dimensional directions (e.g., the horizontal direction and the vertical direction) by the scanning mechanism portion11.

The scanning mechanism portion11is equipped with an angle sensor (or angle speed sensor)14and a servo amplifier13with respect to two axes to be scanned. An image pick-up camera is caused to scan arbitrary vertical and horizontal directions by a camera scanning command signal from a scanning command signal generator portion15to an adder12.

Meanwhile, the image pick-up camera10introduces light waves passing through a converging lens10a, to a reflection mirror lob. The reflection mirror10bis equipped with an angle sensor18and a mirror scanning mechanism portion17which is caused to perform scanning (i.e., reverse scanning) in a direction opposite to the scanning direction of the image pick-up camera10. The scanning command signal generator portion15supplies a signal to the adder19, thereby to drive the mirror scanning mechanism portion17. The scanning command signal generator portion15takes in an angle and an angle speed from the angle sensor14, to control the angle of reverse scanning and the angle of the axis.

Further, the reflection mirror10bis provided with a rotation mechanism21around an optical axis and an angle sensor22, together with the mirror scanning drive portion17and the angle sensor18. Specifically, the rotation mechanism21is constructed by rotatably fixing a scanning drive shaft to a ring211and by rotating the ring211by rotating a motor213through a transmission member212such as a gear or the like. In this case, the angle sensor22may be equipped on the rotation shaft of the motor213. In this manner, the reflection mirror10bis capable of changing the axis of the reverse scanning on the basis of a signal from the scanning command signal generator portion15, like triangular scanning.

Specifically, a command signal for instructing a mirror scanning angle outputted from the scanning command signal generator portion15is converted into a drive signal by a servo amplifier23, and the rotation mechanism21is driven on the basis of the drive signal. When the reverse scanning axis of the reflection mirror10bis inclined as a result, the inclination angle is detected by an angle sensor22and is inputted to a minus input end of an adder24. The adder24carries out a subtraction by reducing an output angle of the angle sensor22from an angle specified by the mirror scanning command signal inputted to a plus input end of this adder. In this manner, the reverse scanning axis of the reflection mirror10bis set to an inclination angle corresponding to the command signal.

Examples of calculating an angle by which the scanning axis of the reflection mirror10bshould be rotated and an angle speed of the reverse scanning will be described below. For example, where the scanning directions of the image pick-up camera10are the horizontal and vertical directions and the reference scanning direction of the reflection mirror10bis the horizontal direction, the angle by which the scanning axis of the reflection mirror10bshould be rotated is expressed as follows.
0=tan−1(ωv/ωh)

The angle speed of the reverse scanning is expressed as follows.
ω=√{square root over (ωv2+ωh2)}
Here, ωv is a scanning angle speed in a vertical direction and ωh is a scanning angle speed in a horizontal direction.

Note that it is apparent that refraction depending on a parallel optical plate may be used although a reflection mirror10bis shown in the present embodiment. In addition, although frequencies of light waves are not limited, it is apparent that the present invention is applicable to overall light waves including ultraviolet light waves, visible light waves, infrared light waves, and the like. Further, in case of applying the present invention to a scanning type laser beam receive apparatus, the image pick-up camera10may be replaced with a laser radar. In this case, a laser beam receiver may be used in place of the image pick-up element10c.

In the structure of the embodiment described above, it is necessary to drive mechanically the reflection mirror, mechanical limitations cannot be avoided, e.g., the adjustable scanning angle speed is limited and the adjustable direction is limited to only one direction. In the following embodiment, this problem will be solved.

FIG. 6shows a structure of a second embodiment of a scanning image pick-up apparatus according to the present invention. InFIG. 6, an image pick-up camera31for taking in a light wave is mounted on a scanning mechanism portion35and is provided so as to freely scan one axial direction (e.g., an azimuth direction) through the scanning mechanism portion35. A sensor portion36is provided on the scanning axis. The light waves adopted are those in a visible region (e.g., a range of 0.4 μm to 0.8 μm) and an infrared region (e.g., a range of 3 μm to 12 μm).

The above scanning mechanism portion35comprises a torquer and a gimbal mechanism and has an input end connected with an output end of an adder38through a servo amplifier37. The adder38has a plus input end connected with a camera scanning command signal output end of a scanning command signal generator portion39.

Specifically, the adder38generates a camera drive signal by obtaining a difference between a camera scanning command signal (e.g., a signal for instructing a scanning angle of the image pick-up camera31) outputted from the scanning command signal generator portion39and an actual scanning angle signal from the sensor portion36, and outputs the camera drive signal to the scanning mechanism portion35. The scanning mechanism portion35controls the scanning angle φ of the image pick-up camera31on the basis of a camera drive signal inputted, such that scanning is performed linearly (ref.FIG. 7A).

The image pick-up camera31is constructed by arranging a converging lens32, an electro-optical deflector34a, and a charge storage type image pick-up element33having a view angle θ on an optical axis. Light waves picked up are converged by the converging lens32and the converged light waves are imaged on the image pick-up element33through the electro-optical deflector34a, thereby to obtain a static view image.

Here, the electro-optical deflector34ahas a structure in which a plurality of prisms made of electro-optical crystal having a so-called electro-optical effect that the refraction factor is changed by applying an electric field are adhered on each other such that optical axes of the prisms are inverted one another. When a light wave enters into the deflector34aapplied with a uniform electric field, the light wave is deflected and injected out. The deflection amount can be expressed in form of a function concerning an applied electric field. This means that the deflection amount can be controlled by an applied voltage.

In this apparatus, therefore, the angle speed in a scanning direction obtained by the sensor portion36is inputted into a deflector control signal generator portion42, thereby to generates a control signal (or angle command signal) corresponding to a return angle equivalent to an angle movement amount. The control signal is converted into a drive voltage by the servo amplifier40athrough the adder41aand is supplied to the electro-optical deflector34a. A voltage change caused by deflection by the electro-optical deflector34ais returned and inputted into the adder41a, thereby to perform deflection corresponding to an angle specified by the control signal.

Where the frame cycle T, exposure time Ta, and charge reading time Tb of the image pick-up element33are set as shown inFIG. 7E, the optical deflection angle can be returned in the reverse direction by an angle equivalent to a scanning angle at the frame cycle, as shown inFIG. 7D, when a synchronous trigger corresponding to the frame cycle T is supplied to the deflector control signal generator portion42at a timing shown inFIG. 7D. Therefore, the light movement angle on the focus plane of the image pick-up element33is constant at the portion of the exposure time Ta, as shown inFIG. 7C, and a static image is thereby obtained, so that a function equivalent to rotation control of a reflection mirror as described before can be realized.

Thus, according to the structure of the present embodiment, an angle speed detection output from the sensor portion36set on a scanning axis (or rotation axis) is used as a feed back signal to the electro-optical deflector34a, and therefore, a return angle equivalent to an angle movement amount depending on scanning by the image pick-up camera31can be supplied to the electro-optical deflector34a. Specifically, an image flow caused by scanning can be equivalently restricted and an image during an exposure time can be stopped statically.

Also in the present embodiment, the image pick-up camera31may be replaced with a laser radar and a laser beam receiver may be used in place of the image pick-up element in case of applying the present invention to a scanning type laser beam receive apparatus.

Although an image flow only in the horizontal direction or the vertical direction can be prevented by using one electro-optical deflector, as described above, prevention of an image flow in case of simultaneous scanning (or two-dimensional scanning) in both the horizontal and vertical directions can be realized by the following third and fourth embodiments.

FIG. 8shows a structure of a third embodiment of a scanning type image pick-up apparatus according to the present invention. Note that those components ofFIG. 8which are the same as those ofFIG. 6are referred to by the same reference symbols and only those portions which are different from those ofFIG. 6will be specifically described below.

The scanning mechanism portion35according to the present embodiment causes an image pick-up camera31to scan two-dimensional directions (which are a horizontal direction and a vertical direction, for example) and a sensor portion36detects a scanning angle in each of the directions.

Meanwhile, the image pick-up camera31is constructed by arranging a converging lens32, a first electro-optical deflector34a, a second electro-optical deflector34b, and a charge storage type image pick-up element33on an optical axis. Light waves taken in are converged by the converging lens32. The light waves converged are deflected in a direction opposite to the horizontal scanning direction by the first electro-optical deflector34aand are deflected in a direction opposite to the vertical scanning direction by the second electro-optical deflector34b. Thereafter, the light waves are imaged on the image pick-up element33, thereby to obtain a static view image.

In this case, a deflector control signal generator portion42controls the first electro-optical deflector34aso as to perform deflection in a direction opposite to the horizontal scanning direction at an equal angle speed through an adder41aand a servo amplifier40a, and also controls the second electro-optical deflector34bso as to perform deflection in a direction opposite to the vertical scanning direction through an adder41band a servo amplifier40b.

As is apparent from the above, the scanning type image pick-up apparatus according to the present embodiment has an independent electro-optical deflector for each of the horizontal and vertical directions, so that corrections can independently made in both the horizontal and vertical directions. Therefore, an image flow can be restricted independently in both the horizontal and vertical directions by independently feeding back the angle speeds in the horizontal and vertical directions to the electro-optical deflectors34aand34b.

FIG. 9shows a structure of a fourth embodiment of a scanning type image pick-up apparatus according to the present invention. Note that those components which are the same as those ofFIG. 6are referred to by the same reference symbols and only those components which are different from those ofFIG. 6will be specifically described below.

A scanning mechanism portion35causes an image pick-up camera31to scan two-dimensional directions (which are a horizontal direction and a vertical direction, for example) like in the third embodiment, and a sensor portion36detects a synthesis scanning angle speed concerning both of the directions.

Meanwhile, the image pick-up camera31is constructed by arranging a converging lens32, an electro-optical deflector34a, and a charge storage type image pick-up element33on an optical axis and by providing a rotation mechanism44for rotating the electro-optical deflector34around the optical axis. Light waves taken in are converged by the converging lens32and the light waves thus converged are deflected in a direction opposite to the scanning direction by the electro-optical deflector34a. The light waves are thereafter imaged on the image pick-up element33, thereby to obtain a static view image.

In this case, a deflector rotation signal generator portion43, an adder41c, and a servo amplifier40care provided for control and drive the rotation mechanism44. The deflector rotation signal generator portion43drives the rotation mechanism44through the adder41cand the servo amplifier40con the basis of synthesis angle speed data from the sensor portion36, thereby to cause the deflection direction of the first electro-optical deflector34bto correspond to the scanning direction, and the deflector control signal generator portion42controls the electro-optical deflector34aso as to perform deflection in a direction opposite to the scanning direction at an equal angle speed through the adder41aand the servo amplifier40a.

As is apparent from the above, the scanning type image pick-up apparatus according to the present embodiment has an electro-optical deflector34awhich is freely rotatable around an optical axis and the electro-optical deflector34ais rotated and controlled such that the moving direction of an image corresponds to the deflection direction of light waves. Specifically, the angle speeds in the horizontal and vertical directions are synthesized with each other thereby to obtain the scanning direction and the scanning angle speed of the image pick-up camera31. The signal concerning the scanning direction is fed back to control rotation of the electro-optical deflector34aaround the optical axis and the signal concerning the scanning angle speed is fed back to control the deflection amount of light waves. Therefore, an image flow can be restricted both in the horizontal direction and the vertical direction.

As described above, according to the structures of the third and fourth embodiments, a scanning type image pick-up apparatus can realize restriction of an image flow without use of a mechanical operating portion. In addition, it is possible to realize a scanning type image pick-up apparatus whose scanning direction is not limited to one direction.

Further, since not only the deflection amount but also the deflection direction can be controlled electrically, it is possible to carry out easily such control which has been difficult to realize by a mechanical means, e.g., inversion of the phase in accordance with inversion of the rotation direction by reciprocal scanning.

Note that the image pick-up camera31may be replaced with a laser radar and a laser beam receiver may be used in place of the image pick-up element10cin case of applying the third or fourth embodiments to a scanning type laser beam receive apparatus.

As has been specifically described above, according to the present invention, it is possible to provide a scanning type image pick-up apparatus and a scanning type laser beam receive apparatus which are capable of obtaining a clear view image over a wide view field and realize highly reliable search with high precision.