Photography – Aerial camera – Support or holder
Patent
1996-08-14
1998-06-09
Gray, David M.
Photography
Aerial camera
Support or holder
348145, 364420, G03B 3900
Patent
active
057650446
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an airborne apparatus for photographing a selected piece of ground surface to provide data of ground image for determining the shape and height of the land.
2. Description of the Prior Art
Air photographs have been widely used for determining the shape and height of a selected piece of land. In general, air photographs are taken of overlapping area sections of a selected piece of land, thereby providing a series of latent images taken at regular intervals on a film. The film is developed, and the developed images are printed.
Alternatively, an airborne scanner-and-line sensor is used to provide required land images in the form of digital data.
Each of the series of the so taken pictures, however, is made up by the collection of image fractions recorded by beams of light reflected in different directions, and therefore such collection of image fractions is not continuous. In addition to this problem the image quality varies with the photosensitivity of the film, developing and printing conditions and other factors.
Nobody can tell what image is like before developing, and therefore, if pictures are found to be defective or useless after developing, the same pictures have to be taken again.
To determine the shape and height of a selected piece of land from air photographs three coordinate points X.sub.0, Y.sub.0 and Z.sub.0 of the instantaneous position of the airborne camera and three inclinations about three coordinate axes .omega., .phi. and u must be determined analytically by using known points (reference points) in the coordinate system. A lot of work is required for finding the reference points in the coordinate system.
To automatize such air photographing-and-analyzing work it is necessary to have an analogue-to-digital conversion occur for the developed film for digitization.
The present invention aimes at photographing continuously a selected piece of land by an airborne three-line sensor camera, and at making a record the land image data in the form of digital data directly from the so taken air photographs. Also, the present invention aimes at effecting feedback control of the attitude of the airborne camera by using attitude data provided by a gyro associated with the three-line sensor camera, thereby setting the camera so that its optical axis may be vertical at all times, thus assuring that distortion-free images may be provided. Finally, the present invention aimes at making a record of each of the attitude data provided by the gyro and the instantaneous position data provided by a GPS in addition to the record of land image data recorded in the form of digital data, thereby permitting a required correction to be made later by using appropriate softwares.
SUMMARY OF THE INVENTION
An airborne photographing apparatus according to the present invention comprises: an airborne three-line sensor camera for taking pictures of a selected piece of land in three directions, that is, forward obliquely, vertically and backward obliquely; a gyro mounted in the housing of the three-line sensor camera for determining the attitude of the camera while photographing; a GPS for providing the instantaneous position data of the camera in the three-dimensional space; a stabilizer for controlling the attitude of the camera to set its optical axis to be vertical at all times, and at the same time for absorbing the vibration of the aeroplane; a data processing unit for processing the attitude data from the gyro and the position data from the GPS and outputting signals for controlling the stabilizer; a data recorder for recording the land image data from the camera, the attitude data from the gyro and the position data from the GPS; an image display for showing the land image data from the camera; and a data analyzer for converting the land image data from the camera into the land image data given in terms of fixed coordinates on the basis of the land image data, attitude data and position data all recorded by the data recorder,
REFERENCES:
patent: 5596494 (1997-01-01), Kuo
Matsumoto Yoshitaka
Murai Shunji
Core Corp.
Gray David M.
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