US3700801A
Expired / Lapsed
US
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Image analysis and correlation system and method
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1966-10-03
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Granted: 1972-10-24
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Expires: 1986-10-03
Abstract
Abstract This invention described improved correlation techniques between images by reducing the optical images into electrical signals. Unreliable techniques eliminate variations due to perspective sun angle and optical distortion by using improved techniques for relating the data received from different sources. An improved system and method is described for the analysis of a reference image to an optically-sensed image which performs a Fourier analyses on the electrical signals representing an image. Spatial frequency component amplitudes and/or phases comprising the Fourier frequency components are isolated and quantified for use in a computer.
Inventors
- 👤 Charles B Dougherty
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:42
CPC Classifications
G; G06; G06E; G06E3/00; G06E3/001; F; F41; F41G; F41G7/00; F41G7/34; F41G7/343; G01; G01S; G01S3/00; G01S3/78; G01S3/782; G01S3/785; G01S3/786; G01S3/7864; G01S3/7865; G06F; G06F3/00; G06F3/002
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
124 words
A method of analyzing the content of an image, including: separating said image into small segments which taken together constitute said image; quantifying the light intensities of each separate constituent small segment of said image; expressing the quantifications of the light intensities of the separate constituent small segments of said image in electrical signals having amplitudes which are a function of said light intensity of each separate constituent small segment of said images; formulating a system of standard components from which any electrical signal can be constituted; identifying all of said standard components which in total constitute each said electrical signal; and converting the identity of each said electrical signal as identified from the standard components it contains into a representation identifying said image.
Claim 2
Independent Claim
124 words
A method of analyzing the content of an image, including: separating said image into small segments which taken together constitute said image; quantifying the light intensities of each separate constituent small segment of said image; expressing the quantifications of the light intensities of the separate constituent small segments of said image in electrical signals having amplitudes which are a function of said light intensity of each separate constituent small segment of said images; formulating a system of standard components from which any electrical signal can be constituted; identifying all of said standard components which in total constitute each said electrical signal; and converting the identity of each said electrical signal as identified from the standard components it contains into a representation identifying said image.
Claim 3
Dependent Claim
47 words
The method according to claim 1 wherein the step of separating said image into small segments includes scanning said image in small segments by scanning and then periodically interrupting the scanning process, and the step of formulating standard components includes the Fourier analysis of said electrical signals.
Claim 4
Independent Claim
351 words
A system for locating points on an image, including; an optical sensor for receiving radiation from an image and developing an electrical signal representative of said image; first means electrically connected to said optical sensor for analyzing said electrical signal into its Fourier components; second means electrically connected to said first means for separating out at least three of said Fourier components for isolated analysis without reference to any other of said Fourier components; third means electrically connected to said second means for sensing the phase of each Fourier component separated out by said second means; fourth means for storing sets of reference phase characteristics of the same frequencies of Fourier components separated out by said second means at points to be located by said system; and computing means electrically connected to said third means and to said fourth means for relating the location of images sensed by said optical sensor to the location of said points to be located by said system, said optical system scans said image at certain scan frequencies and said second means separates out Fourier components having frequencies that are integral multiples of said scan frequencies, the highest frequency of Fourier component separated out by said second means is small relative to said scan frequencies, said optical sensor has an optical axis and said computing means derives a sensor location signal by identifying the point on an image which is coincident with said optical axis, said computing means locates points in terms of the constant phase contours passing through said points, the fourth means registers as Fourier component phase characteristics of said points to be located the constant phase contours intersecting at each said point to be located, the optical sensor is moved by a servo system such that its optical axis passes from point to point on said image; and the computing means is electrically connected to the servo system and supplies control signals to the servo system to cause the servo system to alter thE position of the optical sensor to bring the optical axis into coincidence with each said point to be located.
Claim 5
Independent Claim
351 words
A system for locating points on an image, including; an optical sensor for receiving radiation from an image and developing an electrical signal representative of said image; first means electrically connected to said optical sensor for analyzing said electrical signal into its Fourier components; second means electrically connected to said first means for separating out at least three of said Fourier components for isolated analysis without reference to any other of said Fourier components; third means electrically connected to said second means for sensing the phase of each Fourier component separated out by said second means; fourth means for storing sets of reference phase characteristics of the same frequencies of Fourier components separated out by said second means at points to be located by said system; and computing means electrically connected to said third means and to said fourth means for relating the location of images sensed by said optical sensor to the location of said points to be located by said system, said optical system scans said image at certain scan frequencies and said second means separates out Fourier components having frequencies that are integral multiples of said scan frequencies, the highest frequency of Fourier component separated out by said second means is small relative to said scan frequencies, said optical sensor has an optical axis and said computing means derives a sensor location signal by identifying the point on an image which is coincident with said optical axis, said computing means locates points in terms of the constant phase contours passing through said points, the fourth means registers as Fourier component phase characteristics of said points to be located the constant phase contours intersecting at each said point to be located, the optical sensor is moved by a servo system such that its optical axis passes from point to point on said image; and the computing means is electrically connected to the servo system and supplies control signals to the servo system to cause the servo system to alter thE position of the optical sensor to bring the optical axis into coincidence with each said point to be located.
Claim 6
Dependent Claim
25 words
The system of claim 3 wherein the first and second means are analog devices and the fourth means and the computing means are digital devices.
Claim 7
Dependent Claim
29 words
The system of claim 3 wherein said computing means also provides an electrical signal indicative of the slant range from each point for which a location signal is supplied.
Claim 8
Dependent Claim
49 words
The system of claim 5 wherein the computing means is electrically connected to pass said electrical signals indicative of slant range back to said fourth means; and said fourth means supplies varying values of phase characteristics corresponding to the slant range information received by it from the computing means.
Claim 9
Dependent Claim
164 words
The system of claim 3 wherein said computing means derives a signal approximating the orientation of said optical axis by expressing the location of said optical axis relative to a point to be located in terms of the location of said point to be located plus a certain vector sum by which the point at said optical axis intersects the plane of said image is displaced from said point to be located, said vector is expressed in terms of its components along an ordinate and an abscissa and the difference in phase between said point to be located and said point at which said optical axis intersects the plane of said image is derived by multiplying said vector components by partial derivatives of the constant phase contours of the Fourier components separated out by said second means, and said partial derivatives are stored by said fourth means and are the partial derivatives of the constant phase contours taken at the point to be located.
Claim 10
Dependent Claim
78 words
The system of claim 7 with the additions that said optical sensor is positioned by a servo system; said servo system is electrically connected to receive control signals from said computer means; said computing means derives control signals for said servo system from said vector sum components, and with the additional specification that said control signals supplied by said computing means control said servo system in such manner that said vector sum components are made to approach zero.
Claim 11
Dependent Claim
69 words
The system according to claim 3 with the additions that said optical sensor has an aperture having certain dimensions and that the wavelengths of said Fourier components separated out by said second means are exact sub-multiples of one of said aperture dimensions, said wavelengths of said Fourier components are the lowest possible exact sub-multiples of one of said aperture dimensions consistent with having each wavelength different from the others.
Claim 12
Dependent Claim
28 words
The system according to claim 9 wherein the highest Fourier frequency does not exceed one half the number of image elements on a side of the said aperture.
Claim 13
Independent Claim
128 words
A system for determining location relative to an image including: an optical-electrical transducer for receiving radiation from the image and deriving from said signal representative of said image an image forming constant phase contour, said optical-electrical transducer having as a reference axis indicative of the orientation of said optical-electrical transducer; first means for extracting a plurality of Fourier components from said electrical output signal; second means for storing selected values of said Fourier components at a number of points in said image forming constant phase contours, the number of constant phase contours stored exceeds five, and with the addition that said optical-electrical transducer scans said image at certain scan frequencies and said first means separates out Fourier components having frequencies that are integral multiples of said scan frequencies.
Claim 14
Independent Claim
128 words
A system for determining location relative to an image including: an optical-electrical transducer for receiving radiation from the image and deriving from said signal representative of said image an image forming constant phase contour, said optical-electrical transducer having as a reference axis indicative of the orientation of said optical-electrical transducer; first means for extracting a plurality of Fourier components from said electrical output signal; second means for storing selected values of said Fourier components at a number of points in said image forming constant phase contours, the number of constant phase contours stored exceeds five, and with the addition that said optical-electrical transducer scans said image at certain scan frequencies and said first means separates out Fourier components having frequencies that are integral multiples of said scan frequencies.
Claim 15
Dependent Claim
55 words
The system of claim 11 with the additions that said optical-electrical transducer is positioned by a servo system to vary the orientation of its reference axis; said servo system is electrically connected to rEceive control signals from said third means; and said third means derives control signals for said servo system from said electrical signal.
Claim 16
Dependent Claim
78 words
The system according to claim 11 with the additions that said optical-electrical transducer has an aperture for receiving radiation having certain dimensions and that the wavelengths of said Fourier components separated out by said second means are exact sub-multiples of one of said aperture dimensions, said wavelengths of said Fourier components are the lowest possible exact sub-multiples of one of said aperture dimensions consistent with having each constant phase contour different from all the other constant phase contours.
Claim 17
Dependent Claim
242 words
The system of claim 11 wherein the second means registers as Fourier component phase characteristics of said points the Fourier spatial frequency constant phase contours intersecting at each said point, the optical-electrical transducer is moved by a servo system such that its reference axis passes from point to point on said image; third means electrically connected to the servo system and supplies control signals to the servo system to cause the servo system to alter the position of the optical-electrical transducer to bring the reference axis into coincidence with said point to be located, the third means also provides an electrical signal indicative of the slant range from each point for which a location signal is supplied, said third means derives a signal approximating the orientation of said reference axis by expressing the location of the reference axis relative to a reference point on the image in terms of the location of said reference point plus a certain vector sum by which the point at which reference axis intersects said image is displaced from said reference point, wherein said vector sum is expressed in terms of its components along an ordinate and an abscissa and the difference in phase between said reference point and said point at which said reference axis intersects the plane of said image is derived by multiplying said vector components by partial derivatives of the constant phase contours of the Fourier components separated out by said second means.
Claim 18
Dependent Claim
36 words
The system according to claim 14 with the additional specification that said control signals supplied by said third means control said servo system in such manner that said vector sum components are made to approach zero.
Claim 19
Independent Claim
149 words
A method of analyzing the characteristics of images when viewed from different angles, comprising: scanning an image from a first angle through a first aperture having a certain height and a certain width; transducing radiation from said image passing through said first aperture into first electrical signals representative of the intensity of said radiation; scanning said image through a second aperture at a second angle not identical to said first angle, said second aperture being substantially identical to said first aperture; transducing radiation passing through said second aperture into second electrical signals representative of the intensity of said radiation; separating out selected identical frequencies of Fourier components from said first electrical signal and said second electrical signal; plotting for selected points throughout said image the difference in phase at each said selected point between identical frequencies of Fourier components of said first electrical signal and said second electrical signal.
Claim 20
Independent Claim
149 words
A method of analyzing the characteristics of images when viewed from different angles, comprising: scanning an image from a first angle through a first aperture having a certain height and a certain width; transducing radiation from said image passing through said first aperture into first electrical signals representative of the intensity of said radiation; scanning said image through a second aperture at a second angle not identical to said first angle, said second aperture being substantially identical to said first aperture; transducing radiation passing through said second aperture into second electrical signals representative of the intensity of said radiation; separating out selected identical frequencies of Fourier components from said first electrical signal and said second electrical signal; plotting for selected points throughout said image the difference in phase at each said selected point between identical frequencies of Fourier components of said first electrical signal and said second electrical signal.
Claim 21
Dependent Claim
33 words
The method of claim 16 wherein the step of scanning is performed using a scan pattern and the scan pattern is altered to ascertain the change in phase ascertained in the plotting step.
Claim 22
Dependent Claim
220 words
In combination, first means for optically sensing a certain area and converting the radiation from said area into first electrical signals; said radiation for the optical sensor passes through an aperture and a transmission reticle is positioned in optical series with the aperture, and wherein the aperture is rectangular and has two orthogonal dimensions and the reticle has properties of constantly transmitting light in the direction of a first of said orthogonal dimensions and of transmitting light according to a sinusoidal formula along a second of said orthogonal dimensions, said reticle oscillates at a frequency that is an integral multiple of the frequency of said aperture, and wherein a photo-multiplier tube performs optical-electrical conversion on radiation from said image passing through said reticle, second means for separating out and isolating from said first electrical signals at least one Fourier component thereof; third means for sensing the phase of said Fourier components separated out and isolated by said second means from said first electrical signals; reference means for providing reference electrical signals representative of a reference area; and fourth means for developing second electrical signals from the reference signals and the phase sensed by said third means, said second electrical signals having the characteristic of indicating the distance between said reference area and said area optically sensed by said first means.
Claim 23
Dependent Claim
220 words
In combination, first means for optically sensing a certain area and converting the radiation from said area into first electrical signals; said radiation for the optical sensor passes through an aperture and a transmission reticle is positioned in optical series with the aperture, and wherein the aperture is rectangular and has two orthogonal dimensions and the reticle has properties of constantly transmitting light in the direction of a first of said orthogonal dimensions and of transmitting light according to a sinusoidal formula along a second of said orthogonal dimensions, said reticle oscillates at a frequency that is an integral multiple of the frequency of said aperture, and wherein a photo-multiplier tube performs optical-electrical conversion on radiation from said image passing through said reticle, second means for separating out and isolating from said first electrical signals at least one Fourier component thereof; third means for sensing the phase of said Fourier components separated out and isolated by said second means from said first electrical signals; reference means for providing reference electrical signals representative of a reference area; and fourth means for developing second electrical signals from the reference signals and the phase sensed by said third means, said second electrical signals having the characteristic of indicating the distance between said reference area and said area optically sensed by said first means.
Claim 24
Dependent Claim
100 words
The system according to claim 18 wherein said reticle oscillates over a distance not exceeding the wavelength of its frequency of oscillation, and a photo-detector in optical series with said reticle and said aperture; a synchronous detector electrically connected to said photo-detector; means electrically connected to said synchronous detector for determining the phase of the signal from said synchronous detector, the reticle is oscillated by a servomechanism and the signal from the synchronous detector is fed back to the servomechanism to cause the center of reticle oscillation to be shifted into coincidence with the zero phase point of the image.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |