JPS6058789A - Steroescopic image pickup system - Google Patents

Abstract

PURPOSE:To make stereoscopic image pickup and multiband observation at point just under optical fiber bundles possible with a simple constitution by arranging all optical fiber bundles, which transmit plural pictures directly, one-dimensionally on the focal surface of an optical system and arranging their aperture ends one-dimensionally on a line, which is approximately orthogonal to the advance direction of an image pickup device, nearly in parallel with one another. CONSTITUTION:Aperture ends of optical fiber bundles 9, 10, and 11 are so arranged that images of the ground surface at points just under and at points W(m) distant from these point are picked up. In a position A, images of the ground surface at points P, O, and Q are focused to aperture ends of optical fiber bundles 9, 10, and 11, which are arranged in a focal surface 8 in parallel with one another, by an optical system 27 having a wide allowable incidence angle and are led to photodetectors through optical fiber bundles and are converted to electric signals. The pickup device continues image pickup while advancing in a speed (v), and the image of the ground surface at the point P is focused to the aperture end of the optical fiber bundle in a position B, and this image is combined with information of the ground surface at the point which is focused to the aperture end of the optical fiber bundle 9 in the position A to obtain stereoscopic information of the ground surface at the point P.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an imaging method for obtaining three-dimensional information such as the ups and downs of the earth's surface from an artificial satellite or the like orbiting the earth.

BACKGROUND ART In so-called remote sensing, which observes conditions on the earth's surface from artificial satellites, it is desired to obtain not only two-dimensional information but also three-dimensional information on the earth's surface, especially in the field of resource exploration. It is generally well known that in order to obtain three-dimensional information about a target object, it is necessary to synthesize observation images from two distant points. When trying to obtain a stereoscopic image of the earth's surface from an artificial satellite, it is usually difficult to obtain a stereoscopic image at the same time using a single satellite because the distance to the earth's surface is large. For this reason, it has been proposed to obtain stereoscopic images using vertical movement of satellites.

An example of a stereoscopic imaging method that has been proposed in the past is shown in FIG. In FIG. 1, reference numeral 1 indicates an artificial satellite, and reference numeral 2 indicates an imaging device for performing stereoscopic imaging. The imaging device 2 has two optical systems 3 and 4 for performing stereoscopic imaging, and photoelectric conversion elements 5 and 6 are arranged at the focal plane of each optical system, respectively.

In FIG. 1, an artificial satellite 1 moves at a speed V relative to the earth's surface. At position A, the forward imaging optical system 3 is located at the ground surface P.
is imaged and focused on the photoelectric conversion element 5. Similarly, the rear imaging optical system 4 images the ground surface Q and forms the image on the photoelectric conversion element 6. The satellite 1 continues to take images while moving, and when it reaches position B, the rear imaging optical system 4 takes an image of the ground surface P. Using this image data and the image data of the ground surface P captured by the optical system 3 from the above-mentioned position A, it is possible to obtain three-dimensional information of the ground surface P using the same principle as when stereoscopic vision is normally performed with human eyes. I can do it.

A drawback of this conventional method is that it requires at least two optical systems to obtain stereoscopic information.

Compared to the case where plane information is obtained by imaging only the point directly below the satellite, the increase in the number of optical systems causes a large increase in weight and size, which is a disadvantage for use on a satellite with large restrictions. Furthermore, since it is necessary to precisely set the alignment between the two optical systems, a complicated setting method is also required for mounting the optical systems.

Further, since this type of imaging device is normally required to perform stereoscopic viewing and to image a point directly below, in this case, three optical systems are required as shown in FIG. As is clear from this figure, in the case of , the above-mentioned two weight dimensions and alignment conditions become even more disadvantageous.

As a method using a small number of optical systems, stereoscopic viewing using a configuration as shown in FIG. 3 is also possible. This system has one optical system, and a movable mirror 7-7 is provided on the front side of the optical system as shown in the figure, and stereoscopic viewing is achieved by switching the angle of the movable mirror 7-7. This method has the advantage of being able to select the imaging location by setting the angle of the movable mirror 7, but has the disadvantage that it requires a large movable mechanism and that two locations cannot be captured at the same time, resulting in discontinuous stereoscopic images. .

An object of the present invention is to provide an imaging method that eliminates the drawbacks of these conventional methods and can perform three-dimensional imaging and multiband observation of a direct point with a progressive structure.

The present invention will be explained in detail below with reference to the drawings.

FIG. 4 is an explanatory diagram showing the principle of the three-dimensional imaging method according to the present invention, and FIG. 5 is a partially enlarged view of a portion connecting the imaging plane and the light receiving element in the method shown in FIG. 4. In the figure, 2
Reference numeral 7 indicates a wide-angle optical system for imaging the ground surface, and reference numeral 8 indicates an imaging plane of this optical system.

Reference numerals 9 to 11 designate optical fiber bundles for directly transmitting images, and as shown in the figure, all of them have open ends arranged one-dimensionally on the imaging plane of the optical system. The opening ends are further arranged one-dimensionally on a line that is approximately perpendicular to the traveling direction of the imaging device, and are arranged substantially parallel to each other.

The other open ends of the optical fiber bundles 9-11 are connected to light receiving elements 12-14 as shown in the embodiment of FIG. Also,
Each of the optical fiber bundles 9 to 11 is composed of a collection of seven independent thin optical fibers as an optical signal transmission system. Therefore, the optical signal incident on the entrance aperture end of each optical fiber is transmitted to each pixel that performs photoelectric conversion of the light receiving element without leaking to others. Further, by arranging the output aperture ends of the original fibers 9 to 11 and the photoelectric conversion parts of the light receiving elements 12 to 14 very close to each other or in close contact with each other, leakage to surrounding pixels can be prevented. The image of the ground surface formed at the aperture end from this K is faithfully transmitted to the light receiving element.

A multi-element C0D (charge-coupled device) is used as a light receiving element.
The optical signal supplied to the input end of the fiber bundle is supplied to the light receiving element such as COD, and is output as a time series signal by electronic scanning, similar to high-speed facsimile etc. .

Although the dimensions of the photoelectric conversion parts of the light receiving elements 12 to 14 are very small, the package that accommodates them is large as shown in Figure 5, and there are also extraction electrodes on both sides and a printed circuit part that supplies signals to them. area is required. therefore,
It is very difficult to arrange the light receiving elements 12 to 14 directly within the image plane, which necessitates the use of an optical fiber bundle as in the present invention. In particular, with the recent demand for higher resolution, it has become necessary to have a number of pixels in a scanning line that is several times the number of pixels of one one-dimensional light receiving element. In this case, for example, as shown in FIG. 6, it is possible to take advantage of the characteristics of the system according to the present invention and perform stereoscopic imaging by branching the output ends of the optical fiber bundles 9 to 11 and connecting them to each light receiving element. I can do it.

Furthermore, by using an optical fiber bundle, FIG.
) and (b), it is possible to obtain effects that could not be achieved with the method of arranging the light receiving element directly on the imaging plane. That is, as shown in FIG. 7(a), by curving the input end of the fiber bundle by polishing or the like, it is possible to eliminate the problem of field curvature occurring in the optical system. Also, Fig. 7 (bl
By arranging the fiber bundles in accordance with the distortion aberration caused by the optical system, it is possible to eliminate the influence of the distortion aberration.

As shown in FIG. 4, the open ends of the optical fiber bundles 9 are arranged so as to image the ground surface in front of the JW (rr11) from the point directly below them. Similarly, the open ends of the fiber bundles 10 and 11 are also located directly below the points directly below them. and W (E) are arranged so as to image the ground surface behind them.

As shown in the figure, the optical system 27 has a large allowable angle of incidence.
, the ground surface P, 0. The images of Q are respectively formed on the open ends of the optical fiber bundles 9, 10 and 11 arranged parallel to each other in the image forming plane 8, and guided by the optical fiber bundles to a light receiving element where they are converted into electrical signals. be done. The imaging device continues imaging while moving at a speed V, and at position B, the optical fiber bundle 1
An image of the ground surface P is formed at the aperture end of 1, and three-dimensional information of the ground surface P is obtained together with the information of the ground surface P imaged at the aperture end of the light 7 eyeper bundle 9 at the aforementioned position A. .

The output signals of the light receiving elements 12 to 14 connected to the optical fiber bundle are processed by the signal processing circuit 15. The signal is sent to the ground station via the transmitter 16 and antenna 17.

FIG. 8 shows an example of a system diagram of a ground station device when the system according to the present invention is used. In the figure, 18 is a receiving antenna, 19 is a receiving demodulator, and 20 is a distribution circuit. The output signals 21, 22 and 23 of the distribution circuit 20 are respectively
It corresponds to the output signal of 2113.14.

As shown in Figure 4, if the distances between the imaging position directly below the satellite and the front and rear imaging positions are each W (ml), the time it takes for the satellite to move from position A to position B is W 2τ = - (sec) That is, after an image of the ground surface P is formed on the open end of the optical fiber bundle 9, an image of the same ground surface is formed on the open end of the optical fiber bundle 11 2τ seconds later.

Therefore, as shown in FIG. 8, if a relative time delay of 2τ (sec) is given to the demodulated output 21 corresponding to the light receiving element 12, the output of the delay circuit 24 becomes the demodulated output 23 corresponding to the light receiving element 14. The image processing and recording section 25 can obtain stereoscopic image information using signals obtained by imaging the same ground surface from different angles.

Similarly, τ
By providing a time delay of (sec), information on the same ground surface can be input to the image processing recording section.

The delay circuit shown in FIG. 8 can be configured with a digital memory circuit or the like, and on the transmitting side of FIG. By providing a time delay, it is also possible to eliminate the delay circuit in the receiving section.

Further, in the embodiments described above, an example was explained in which a one-dimensional pixel arrangement, for example, a -dimensional COD, was used as a light receiving element, but since the method according to the present invention uses an optical fiber bundle, It is also clear that a two-dimensional COD in which pixels are arranged in a plane as shown in the figure can be used. In this case, as shown in Figure 1, the arrangement of the aperture ends on the imaging plane side of the optical fiber bundle is the same as in Figures 5 and 6, but the output end on the light receiving element side is It is branched into a number corresponding to , and connected to the corresponding pixel position.

This method makes it possible to effectively utilize the extremely large number of pixels that the two-dimensional COD has, making it possible to perform high-resolution stereoscopic imaging.

As is clear from the above description, the imaging method according to the present invention can have various applied configurations as shown below.

(2) Stereoscopic viewing using the light receiving elements connected to the fiber bundles 9 and 11, and multiband observation using the light receiving element 10 connected to the fiber bundle 10.

2) In the above configuration, switching reception such as stereoscopic viewing only, multiband observation only, etc. is to be performed by commands from the ground.

3) Make the observation wavelength ranges of fiber bundles 9 and 10.11 the same, and obtain stereoscopic tremors @j between 9.11, 10, 1.1, and 9, 10, respectively. Alternatively, one of them can be made redundant and used as a spare.

It should be noted that it is clear from the above description that the method of the present invention can also be applied to three-dimensional observation from a flying object such as an aircraft.

As described above, according to the present invention, a compact, lightweight, and highly reliable stereoscopic imaging system can be obtained with an extremely simple configuration.

[Brief explanation of drawings]

Figure 1 is a conceptual diagram showing an example of a conventional stereoscopic imaging system;
The figure is a conceptual diagram when imaging a direct point using the method in Figure 1, Figure 3 is a conceptual diagram showing another example of the conventional stereoscopic imaging method, and Figure 4 is a conceptual diagram showing another example of the conventional stereoscopic imaging method.
5 is an enlarged perspective view showing an example of the configuration of the fiber bundle and light receiving element section in FIG. 4, and FIG. FIG. 7 is a block diagram of a satellite transmitting unit that adopts the above method. It is a partially enlarged perspective view showing the configuration of a fiber bundle and a light receiving element section when a two-dimensional CCD 1 is used in the system of the present invention. In the figure, 1...satellite, 2.2'...
・Imaging device, 3.4...Optical system, 5,6...
...Photoelectric conversion element, 7...Movable mirror, 27
...Wide angle optical system, 8...Optical system 27
Image plane, 9-11...Fiber bundle, 12-1
4... Light receiving element, 15... Signal processing circuit, 16... Transmitting unit, 17... Transmitting antenna, 18... Receiving antenna , 19...
...Reception demodulation section, 20...Distribution circuit, 21-2
3...Distribution circuit, output signal of 20, 24.26
. . . Delay circuit, 25 . . . Image processing recording section. 0t 爲4Figure 7Figure 4 Figure 8

Claims (1)

[Claims] In a three-dimensional imaging method that obtains a three-dimensional image of an object to be imaged, one aperture end is arranged within the same imaging plane of an imaging optical system in an imaging device that moves relative to the object to be imaged, and the other an optical fiber bundle whose aperture ends are coupled to a photoelectric conversion section of a multi-element photoelectric conversion element, the aperture ends in the imaging plane having a one-dimensional array configuration of at least two sets, and the at least two sets of aperture end arrays The imaging device is arranged substantially perpendicularly to the moving direction of the imaging device and parallel to each other, and images at least the front and rear of the imaging device in the moving direction, and extracts imaging data of the front and rear from the multi-element photoelectric conversion element. , a stereoscopic imaging method characterized in that the stereoscopic image is obtained based on this data.