JPS6039994A - Stereoscopic image pickup system - Google Patents

Abstract

PURPOSE:To attain stereoscopic image pickup and multi-band observation at a point directly under an image pickup device by providing plural photodetectors arranged in parallel with each other to the image forming plane of a wide angle optical system in the image pickup device. CONSTITUTION:An image of ground surfaces O, P and Q is formed respectively on photodetectors 11, 9 and 10 arranged in parallel with each other in the image forming plane 8 at a position A by an optical system 27 having a large permissible incident angle in the image pickup device 2'. A satellite 1 continues image pickup while being progressed in a velocity (v), the ground surface P is image picked up by a rear image pickup element 10 at a position B and the stereoscopic information of the ground surface P is obtained by the information image picked up by the photodetector 9 at the point A.

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.

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 three-dimensional image of the earth's surface from an artificial satellite, it is usually difficult to obtain a three-dimensional image at the same time using one satellite because the distance to the earth's surface is large. For this reason, it has been proposed to obtain stereoscopic images by utilizing the positional movement of satellites.

An example of a stereoscopic imaging method that has been proposed in the past is shown in FIG. In FIG. 1, ■ indicates an artificial satellite, and 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 a photoelectric conversion element 5.6 is arranged at the focal plane of each optical system.

In FIG. 1, one artificial satellite l 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 l continues to take images while it is moving, and when it reaches the position B, the rear imaging optical system 4 takes an image of the ground surface P. Based on this image data and the image data of the ground surface P captured by the optical system 3 from the above-mentioned position A, 1. Obtain stereoscopic information of the ground surface P using the same principle as when stereoscopic viewing is performed with normal 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 required for mounting the optical systems.

Furthermore, 1. Usually, this type of imaging device is required to perform stereoscopic viewing and also to perform imaging of a point directly below.

In this case, three optical systems are required as shown in FIG. As is clear from this figure, in this case, the aforementioned 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. In this system, there is only one YS system, and a movable mirror 7 is provided in front of it as shown in the figure, and stereoscopic viewing is achieved by changing the angle of the movable mirror 7.

This method has the advantage of being able to select the imaging location by setting the movable mirror 70 angle, but has the disadvantages of requiring measures for large towns and the inability to capture images at two locations at the same time, resulting in discontinuous stereoscopic images. There is.

It is an object of the present invention to provide an imaging method that eliminates the drawbacks of these conventional methods and can perform stereoscopic imaging and multiband observation of a direct point with a simple configuration.

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 stereoscopic imaging method according to the present invention, and FIG. 5 shows an example of a system diagram of a satellite transmitter using this method. In the figure, 27 is a wide-angle optical system for imaging the ground surface, 8 is an imaging plane of this optical system, and 9 to t'i are all light receiving elements arranged within the imaging plane of this optical system. Adashi,
9 is for front imaging.

Reference numeral 10 denotes a light-receiving element for rear imaging, and ti represents a light-receiving element for directly below-point imaging.

As shown in FIG. 4, the optical system 7 with a large permissible angle of incidence allows the ground surface to be 0.05 m at position A. The images P and Q are respectively formed on light-receiving elements 11°9 and to arranged in parallel to each other within the image plane 8. The satellite continues to take images while moving at a speed V, and at the position meter 1, the rear image sensor 1O takes an image of the ground surface P, and based on the information taken from the above-mentioned position A by the light receiving element 9, the ground surface P is taken. Stereoscopic information of P can be obtained.

A photoelectric conversion element such as a multi-dimensional COD (charge-coupled device) is used as the light-receiving element, and a time-series signal is outputted by electronic scanning, similar to a high-speed facsimile. The output signals of these light receiving elements 9, 10.11 are processed by the signal processing circuit 12.1 in FIG. The signal is sent to the ground station via the transmitter 13 and antenna 14.

FIG. 6 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, 15 is a receiving antenna, 16 is a receiving demodulator, and 17 is a distribution circuit. The output signals 18 and 20°19 of the distribution circuit 17 correspond to the output signals 9.11 and to of the transmitting section, respectively.

As shown in Figure 4, the imaging position directly below the satellite and the front.

Letting the distance to the rear imaging position be VVtnl, τ
? The time it takes for star j to move from position to position B is W 2τ=-(formula). That is, after the front imaging light-receiving element 9 images the ground surface P, the rear imaging light-receiving element 1O images the same ground surface 2τ seconds later. Therefore, as shown in FIG. 6, for the demodulated output 18 corresponding to the light receiving element 9,
If a relative time delay of 2τ (east) is given, delay circuit 2
The output 1 is a signal obtained by imaging the same ground surface from a different angle as the demodulated output 19 corresponding to the light receiving element 10. The 1 image processing and recording section 22 can obtain stereoscopic image information.

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

The delay circuit shown in FIG. 6 can also be configured with a digital memory circuit, etc. Also, in the transmitter section of FIG. By doing so, it is also possible to eliminate the delay circuit in the receiving section.

As is clear from one or more of the explanations, the imaging method according to the present invention can have various applied configurations as shown below.

1. Light receiving element 9. For stereoscopic viewing, receiving element 11
simultane band observation using multiple photodetectors.

2. In the above configuration, reception can be switched between stereoscopic viewing only, multiband observation only, etc. based on commands from the ground.

3. The wavelength ranges of the light-receiving elements 9 to xi are made the same, and three-dimensional information is obtained between 9° and 10, between to and tt, and between 9 and 10. Alternatively, one of them can be made redundant and used as a spare.

It should be noted that it is clear from the above explanation that this method 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.
The figure is a conceptual diagram showing an embodiment of the stereoscopic imaging method according to the present invention.
FIG. 5 is a block diagram of a satellite transmitter employing the system shown in FIG. 4, and FIG. 6 is a block diagram of a ground station device. In the figure, l...Satellite, 2.2'...
・Imaging device. 3.4... Optical system, 5, 6... Photoelectric conversion element, 7... Movable Mi7-, 27...
wide-angle optical system, 8...) as the imaging plane of system 27,
9-11... Light receiving element, 12... Signal processing circuit, 13...- Transmitting section, 14...
Transmitting antenna, 15...Receiving antenna, 16.
...Receiving circular part, 17...Distribution circuit, 1
8-20... Output signal of distribution circuit 17, 21.
23... Delay circuit, 22... Image processing recording section. Agent Patent Attorney Susumu Uchihara - Shichiriki 4 Figure / U 576 - / Zoto 6 Close

Claims (1)

[Claims] In a three-dimensional imaging method in which a three-dimensional image of the object is obtained using an imaging device that moves relative to the object, two or more images are parallel to each other and parallel to the same imaging plane of the imaging optical system in the imaging device. It has a multi-element photoelectric conversion element that is arranged substantially perpendicular to the movement and captures images at least in front and back in the movement direction, and the three-dimensional image is obtained from the front and rear image data obtained from the multi-element photoelectric conversion element. A three-dimensional imaging method that is characterized by the following: