Infrared face detection and recognition system
First Claim
1. A detection system comprising:
- a first array of detector pixels having a first field of view;
a second array of detector pixels having the first field of view;
a subtractor connectable to each pixel pair of the first and second arrays; and
a comparator connected to the subtractor; and
wherein;
the first sensing array has a sensitivity to light in a lower portion of a reflective infrared spectrum;
the second sensing array has a sensitivity to light in an upper portion of a reflective infrared spectrum;
a pixel pair includes a first pixel at a location of the first array of detector pixels of the first array which a one-to-one correlation with a second pixel of the pixel pair at a corresponding location of the second array of detector pixels;
the subtractor detects the differences of magnitudes of output signals from the first and second pixels of each pixel pair and output a magnitude difference signal for each pixel pair; and
a comparator compares the magnitude difference signals to a certain threshold value and select the pixel pairs having magnitude difference values on one side of the threshold value.
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Accused Products
Abstract
A face detection and recognition system having several arrays imaging a scene at different bands of the infrared spectrum. The system may use weighted subtracting and thresholding to distinguish human skin in a sensed image. A feature selector may locate a face in the image. The face may be framed or the image cropped with a frame or border to incorporate essentially only the face. The border may be superimposed on an image direct from an imaging array. A sub-image containing the face may be extracted from within the border and compared with a database of face information to attain recognition of the face. A level of recognition of the face may be established. Infrared lighting may be used as needed to illuminate the scene.
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Citations
27 Claims
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1. A detection system comprising:
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a first array of detector pixels having a first field of view; a second array of detector pixels having the first field of view; a subtractor connectable to each pixel pair of the first and second arrays; and a comparator connected to the subtractor; and wherein; the first sensing array has a sensitivity to light in a lower portion of a reflective infrared spectrum; the second sensing array has a sensitivity to light in an upper portion of a reflective infrared spectrum; a pixel pair includes a first pixel at a location of the first array of detector pixels of the first array which a one-to-one correlation with a second pixel of the pixel pair at a corresponding location of the second array of detector pixels; the subtractor detects the differences of magnitudes of output signals from the first and second pixels of each pixel pair and output a magnitude difference signal for each pixel pair; and a comparator compares the magnitude difference signals to a certain threshold value and select the pixel pairs having magnitude difference values on one side of the threshold value. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A human detection system comprising:
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a multi-band camera having first and second outputs; a subtractor connected to the first and second outputs; a thresholder connected to the subtractor; a feature selector connected to the thresholder; a framer connected to the thresholder; a pixel integrator connected to the framer and the first output; an extractor connected to the integrator; a recognition system connected to the extractor. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for detecting a face in a scene, comprising:
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capturing a first image of the scene with a first sensing array sensitive to a first band of reflective infrared light; capturing a second image of the scene with a second sensing array sensitive to a second band of reflective infrared light; and wherein; the first image comprises m×
n pixels;the second image comprises m×
n pixels;the first and second images have the same field of view of the scene; each pixel P(i,j)1 of the first image is located at an ith row and a jth column; each pixel P(i,j)2 of the second image is located at an ith row and a jth column; 1≦
i≦
m;1≦
j≦
m;each pixel P(i,j)1 of the first image has a counterpart pixel P(i,j)2 in the second image in a one-to-one mapping of the first image to the second image; a difference intensity pixel Δ
IP(i,j) may be determined from an intensity of each pixel IP(i,j)1 of the first image and each counterpart pixel IP(i,j) of the second image, for all of the pixels of the first and second images;each difference intensity pixel Δ
IP(i,j) has an intensity value that is measured against an intensity threshold value and has its value nullified if it does not meet a certain range of intensity values relative to the intensity threshold value, and becomes a thresholded difference intensity pixel TΔ
IP(i,j);each thresholded difference intensity pixel together with each other thresholded difference intensity pixel forms a third image having a one-to-one mapping of pixels to the first and second images; and features of a face are sought, and if found, a face is detected in the third image and a frame is scribed as frame pixels in the third image around the face. - View Dependent Claims (18, 19, 20, 21, 22)
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23. Means for detecting faces, comprising:
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means for obtaining a first image with a first field of view of a scene at a lower reflective infrared band of light; means for obtaining a second image with the first field of view of the scene at an upper reflective infrared band of light; means for subtractively combining the first and second images into a third image; means for thresholding the pixels of the third image to result in a fourth image having only the pixels meeting a set threshold value; means for finding features of a face in the fourth image; means for inserting a frame around the face based on the features; and means for transferring the frame to be around the face in the first image. - View Dependent Claims (24, 25, 26, 27)
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Specification