Method and apparatus for scanning an object
First Claim
1. A method for producing an image of the surface of an object, comprising the steps:
- a) flying over the object while periodically scanning the object in a plurality of scanning sweeps in a scanning direction transversely to the flying direction with a scanner comprising a row of individual equal-sized detectors oriented transversely to the direction of scanning,b) during each scanning sweep the output signal of each individual detector is scanned in a plurality of short scanning periods Δ
t each corresponding to a small incremental angle of the object for generating a sequence of fundamental detector signals, whereby the fundamental detector signals become associated with respective fundamental object pixels each of whose width is perpendicular to the said scanning direction and each of whose size is a function of the distance range of the object pixel from the scanner,c) storing the fundamental detector signals of all individual detectors of the row for each scanning sweep,d) combining the stored fundamental detector signals to form therefrom an image of the object composed of a grid of standard object pixels (B) having the same size independently of their distance range from the scanner and such that during each scanning sweep a strip (j) corresponding to the surface of the object is formed, each said strip, in its width and length, being respectively composed of a constant quantity of standard object pixels.
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Accused Products
Abstract
The invention is directed to a method and an apparatus for scanning the terrain surface and other objects transversely to the flight direction or direction of motion of the scanner with a detector row arranged perpendicularly to the direction of scanning and containing several individual detectors of equal size, wherein the terrain- or object strip to be scanned is divided into various distance ranges, within which the fundamental detector signals within the detector row as well as of consecutive exposure periods are collated respectively in such a way by averaging, that the collated individual signals form or cover respectively one object pixel of approximately constant magnitude independent of the scanning distance, and wherein these object pixels stand always at right angles with respect to the scanning beam and where each scanning sweep produces a terrain- or object strip with approximately equal object pixel size as well as constant object pixel number along the width and length of the scanned strip. This method and apparatus eliminates the known deficiency of opto-mechanical scanners, whose scanned strips have changeable strip widths as a function of the scanning distance.
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Citations
18 Claims
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1. A method for producing an image of the surface of an object, comprising the steps:
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a) flying over the object while periodically scanning the object in a plurality of scanning sweeps in a scanning direction transversely to the flying direction with a scanner comprising a row of individual equal-sized detectors oriented transversely to the direction of scanning, b) during each scanning sweep the output signal of each individual detector is scanned in a plurality of short scanning periods Δ
t each corresponding to a small incremental angle of the object for generating a sequence of fundamental detector signals, whereby the fundamental detector signals become associated with respective fundamental object pixels each of whose width is perpendicular to the said scanning direction and each of whose size is a function of the distance range of the object pixel from the scanner,c) storing the fundamental detector signals of all individual detectors of the row for each scanning sweep, d) combining the stored fundamental detector signals to form therefrom an image of the object composed of a grid of standard object pixels (B) having the same size independently of their distance range from the scanner and such that during each scanning sweep a strip (j) corresponding to the surface of the object is formed, each said strip, in its width and length, being respectively composed of a constant quantity of standard object pixels. - View Dependent Claims (2, 3, 4, 5)
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6. Apparatus for scanning in a plurality of scanning sweeps a terrain surface or other objects transversely to the direction of flight or direction of motion (X) of a scanner with a scanning element and a detector row arranged at right angles to the scanning direction (Y), said scanner comprising a plurality (M) of individual detectors (D) of equal size, means connected to the scanner for forming detector signals and therefrom, by scanning the output signal of each individual detector within each scanning sweep over a plurality of short scanning periods Δ
- ty, object pixels of equal size (Bx =By =B) independently of the scanning distance (E) or the scanning angle (ω
), said object pixels (B) extending always perpendicularly to the scanning direction and said object pixels always forming a uniform grid with constant object pixel quantity (n) within the constant width (Bn) of the scanned object strip over the entire region of one sweep, said means for forming said detector signals comprising means for digital control of the scanning period Δ
t/y in accordance with the following formula;
##EQU13## where E is the scanning distance, h is the flight altitude, ω
is the scanning angle, and ω
the angular velocity of the scanning element. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
- ty, object pixels of equal size (Bx =By =B) independently of the scanning distance (E) or the scanning angle (ω
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14. Reconnaissance apparatus comprising means for scanning an object while flying over it, an array of individual, equal-sized detectors (1) arranged in a row transverse to the flying direction for generating signals during the scanning over consecutive exposure periods forming a non-uniform pixel grid image representative of the scanned object, and means for transforming the non-uniform pixel grid image into a regular pixel grid image to achieve a more uniform resolution;
- said transforming means comprising
a) a first memory (3) for storing the signal of individual detectors (1) within one exposure period, b) a first processor (4) for combining signals of the individual detectors (1) into groups, c) a second memory (5) for storing the signals of consecutive exposure periods corresponding to each of the groups, d) a second processor (9) for combining individual groups of consecutive exposure periods for generation of object pixels, and e) a bulk storage (11) for storing the object pixels. - View Dependent Claims (15, 16, 17, 18)
- said transforming means comprising
Specification