EP0504633A2
Expired / Lapsed
EP
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Minimum difference processor
Assignee: Raytheon Co
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Filing: 1992-02-26
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Granted: —
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Expires: 2012-02-26
Abstract
Abstract A process for reducing background clutter of a scene, and thus, isolating an object of interest. The process includes calculating a minimum output from a plurality of appropriately configured anti-median filters representing a minimum difference processor (MDP) filter. In a first preferred embodiment, the MDP filter includes a (5 x 5) matrix of elements wherein each element has an intensity value representation of the scene. A first anti-median filter array is configured as a horizontal array of 5 pixel elements in which the center element of the matrix is the center element of the horizontal array. A median value of the 5 elements of the horizontal array is determined, and is subtracted from the value of the center element to determine an anti-median value of the horizontal array. The same process is performed for a vertical 5 element anti-median array, and two diagonal 5 element anti-median arrays, all including the center element of the matrix as the center common element of the arrays. Once the anti-median value of each array is determined the lowest anti-median value is outputted as the output of the MDP filter. In a second preferred embodiment, the values of the remaining elements of the matrix which were not included in any of the horizontal, vertical or diagonal arrays described above are subtracted from the center element of the matrix. Again, the lowest value from the group of anti-median values together with the remaining subtracted values is outputted as the output of the MDP filter. This process enables the background clutter of the scene to be substantially suppressed or eliminated.
Inventors
- 👤 Jack M. Sacks
- 👤 Thomas K. Lo
- 👤 Nam D. Banh
- 👤 Charles A. Mcnary
- 👤 Franklin J. Meyers
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 13:04
CPC Classifications
G; G06; G06T; G06T5/00; G06T5/73; G06T5/75; G06T5/20; G06T7/00; G06T7/10; G06T7/11; G06T7/194; G06T7/20; G06T7/215; G06T2207/00; G06T2207/20; G06T2207/20024; G06T2207/20032
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
179 words
A method of image processing comprising the steps of: defining a matrix having a plurality of individual elements, each element having a corresponding value representative of the intensity of the image at the location of that element; defining a single element of the plurality of elements of the matrix having a value; determining a median value of the elements of a first array of elements in which the defined single element is an element of the first array; determining a median value of the elements of a second array of elements in which the defined single element is an element of the second array; subtracting the median value of the first array from the value of the single element of the matrix to determine an anti-median value of the first array; subtracting the median value of the second array from the value of the single element of the matrix to determine an anti-median value of the second array; and outputting the lowest value of the anti-median value of the first array and the anti-median value of the second array.
Claim 2
Dependent Claim
20 words
The method according to Claim 1 wherein the single element is a middle element of the first and second array.
Claim 3
Dependent Claim
52 words
The method according to Claim 1 wherein the first array is a horizontal array and the second array is a vertical array and the single element is a center element of the matrix such that the horizontal array and vertical array define a coordinate axis with the center element at the origin.
Claim 4
Dependent Claim
126 words
The method according to Claim 3 further comprising the steps of: determining a median value of a third array of elements of the matrix which includes the center element of the matrix as the center of the third array; determining a median value of a fourth array of elements which includes the center element of the matrix as the center of the fourth array; determining an anti-median value of the third array by subtracting the median value of the third array from the center value of the matrix; determining an anti-median value of the fourth array by subtracting the median value of the fourth array from the center value of the matrix; and outputting the lowest anti-median value of the first, second, third or fourth array.
Claim 5
Dependent Claim
40 words
The method according to Claim 4 wherein the third array is a diagonal array oriented at 45° to the horizontal and vertical array and the fourth array is a diagonal array oriented at 135° to the horizontal and vertical arrays.
Claim 6
Dependent Claim
31 words
The method according to Claim 1 wherein the matrix is a (5 x 5) matrix having 25 elements and each of the first and second arrays is a five element array.
Claim 7
Dependent Claim
82 words
The method according to Claim 5 further comprising the steps of subtracting at least one of the remaining elements of the matrix which was not included in any of the horizontal, vertical, or diagonal arrays from the value of the center element of the matrix to determine at least one subtracted value and outputting the lowest value of the anti-median values of the horizontal, vertical or diagonal arrays and the at least one subtracted value of the at least one remaining element.
Claim 8
Dependent Claim
43 words
The method according to Claim 7 wherein at least one remaining element is every element not included in any of the horizontal, vertical, or diagonal arrays and the at least one subtracted value is a subtracted value for each of the remaining elements.
Claim 9
Dependent Claim
18 words
The method according to Claim 1 wherein the matrix is scanned across an image representation of a scene.
Claim 10
Dependent Claim
16 words
The method according to Claim 9 wherein the image process is used for background clutter suppression.
Claim 11
Dependent Claim
97 words
The method according to Claim 1 further comprising the steps of: determining a median value of the elements of a plurality of other arrays of elements other than the first and second array in which the defined single element is an element of each of the other arrays; subtracting the median value of each of the plurality of other arrays from the value of the single element to determine an anti-median value of each of the plurality of other arrays; and outputting the lowest anti-median value of the plurality of arrays including the first and second array.
Claim 12
Dependent Claim
27 words
The method according to Claim 4 wherein at least one of the plurality of arrays and the first and second array include every element of the matrix.
Claim 13
Dependent Claim
189 words
A process for eliminating background clutter in an image scene comprising the steps of: defining a matrix having a plurality of individual elements aligned in rows and columns, each element having a corresponding value representative of the intensity of the image at the location of that element; defining a center element having a center value of the matrix; determining a median value of the elements of a horizontal array of elements in which the defined center element is a middle element of the horizontal array; determining a median value of the elements of a vertical array of elements in which the defined center element of the matrix represents a middle element of the vertical array; subtracting the median value of the horizontal array from the value of the center element of the matrix to determine an anti-median value of the horizontal array; subtracting the median value of the vertical array from the value of the center element of the matrix to determine an anti-median value of the vertical array; and outputting the lowest value of the anti-median value of the horizontal array and anti-median value of the vertical array.
Claim 14
Independent Claim
177 words
An apparatus for reducing background clutter of an image scene comprising: means for defining a matrix including a plurality of elements; means for defining a single element of the plurality of elements of the matrix; means for determining a median value of the elements of a first array of the plurality of elements which includes the single element as the center element of the first array; means for determining a median value of the elements of a second array of the plurality of elements which includes the single element as the center element of the second array; means for subtracting the median value of the elements of the first array from the value of the single element of the matrix to determine an anti-median value of the first array; means for subtracting the median value of the second array from the value of the single element of the matrix to determine an anti-median value of the second array; and means for outputting the lowest value of the anti-median values of the first array and the second array.
Claim 15
Dependent Claim
17 words
The apparatus according to Claim 14 wherein the single element is a center element of the matrix.
Claim 16
Dependent Claim
116 words
The apparatus according to Claim 14 further comprising: means for determining a median value of a third array of elements of the matrix which includes the single element of the matrix as the center element of the third array; means for determining a median value of a fourth array of elements which includes the single element of the matrix as the center element of the fourth array; means for determining an anti-median value of each of the third and fourth arrays by subtracting the median value of the third and fourth arrays from the value of the single element of the matrix; and outputting the lowest anti-median value of the first, second, third, or fourth array.
Claim 17
Dependent Claim
62 words
The apparatus according to Claim 16 wherein the first and second arrays are a horizontal array and a vertical array perpendicular to each other and defining a coordinate axis, and the third and fourth arrays are diagonal arrays wherein the third array is at approximately 45° to the coordinate axis and the fourth array is at approximately 135° to the coordinate axis.
Claim 18
Dependent Claim
67 words
The apparatus according to Claim 16 further comprising means for subtracting the remaining elements of the matrix which were not in any of the first, second, third or fourth arrays from the value of the single element of the matrix and means for outputting the lowest value of the anti-median values of the first, second, third or fourth arrays or the subtracted values of the remaining elements.
Claim 19
Dependent Claim
31 words
The apparatus according to Claim 14 wherein the matrix is a (5 x 5) matrix having 25 elements and each of the first and second arrays is a five element array.
Claim 20
Dependent Claim
16 words
The apparatus according to Claim 14 further comprising means to scan the matrix across the image.
References Cited (Backward Citations)
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