Method for replacing the background of an image
First Claim
1. A digital processing method of replacing an original background of a visible light image of a scene with a predetermined replacement background, said method comprising the steps of:
- making a first infrared (IR) image of the scene at a first time while illuminating the original background with first IR radiation having a first intensity;
measuring the intensity of IR radiation at each pixel of said first IR image;
making a second IR image of the scene at a second time after deactivating said first IR radiation, while illuminating a foreground of the scene with second IR radiation having a second intensity less than said first intensity;
measuring the intensity of IR radiation at each pixel of said second IR image;
making the visible light image of the scene at a third time while illuminating the scene with visible lighting;
generating a transformed mask distinguishing said foreground from said original background by producing a difference image (DIFF), a binarized image, a binary mask and a gray-scale mask; and
producing a modified visible light image by blending said visible light image with said predetermined replacement background, using said transformed mask.
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Accused Products
Abstract
The present invention is useful in taking a visible light image for identification and other purposes without the requirement of a photobooth, regardless of the background of the visible light image. The original background of the visible light image is replaced with a preselected background. Two IR images with different intensities of IR illumination in the foreground and background regions of the scene, respectively, are compared to produce a difference image of light intensity differences between corresponding pixels of the two images. A binarized image is generated by binarizing the difference image with respect to a predetermined threshold value θ. A connectivity constraint is used to generate a binary mask from the binarized image, then a gray-scale mask is produced by multiplying the binary mask times a preselected modulation function of the difference image. Warping the gray-scale mask produces a transformed mask. Finally, the background replaced visible light image is generated by blending the transformed mask with the visible light image, and replacing the original background with the preselected background.
130 Citations
14 Claims
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1. A digital processing method of replacing an original background of a visible light image of a scene with a predetermined replacement background, said method comprising the steps of:
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making a first infrared (IR) image of the scene at a first time while illuminating the original background with first IR radiation having a first intensity; measuring the intensity of IR radiation at each pixel of said first IR image; making a second IR image of the scene at a second time after deactivating said first IR radiation, while illuminating a foreground of the scene with second IR radiation having a second intensity less than said first intensity; measuring the intensity of IR radiation at each pixel of said second IR image; making the visible light image of the scene at a third time while illuminating the scene with visible lighting; generating a transformed mask distinguishing said foreground from said original background by producing a difference image (DIFF), a binarized image, a binary mask and a gray-scale mask; and producing a modified visible light image by blending said visible light image with said predetermined replacement background, using said transformed mask. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification