Polaroid Corporation

Yibing Yang

Munib A Wober

Michael L Reisch

Ibrahim Hajjahmad

Lon E Sunshine

F Richard Soini

John C Bowman

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 .theta.. 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.

Method for replacing the background of an image

A method or system for structuring an image which corresponds to an original array of pixels, as a forward discrete even cosine transform (DCT) pyramid having a predetermined number of levels where each level is associated with a different DCT frequency band, includes, respectively, the steps or functionality of: partitioning the original array into blocks of overlapped pixels; taking a DCT of each block of overlapped pixels to generate blocks of first level DCT coefficients forming a first level of the DCT pyramid; storing the first level of the DCT pyramid; selecting and storing at least one of the first level DCT coefficients of each block of first level DCT coefficients into a first temporary array; partitioning the first temporary array into blocks of overlapped coefficients; and taking a DCT of each block of overlapped coefficients of the first temporary array to generate blocks of second level DCT coefficients forming a second level of the DCT pyramid. Additional levels can be created by repeating the previous steps, and the processed image can be restored by reversing the above sequence of steps using inverse discrete even cosine transforms.

Structuring a digital image into a DCT pyramid image representation

The invention relates to a novel process and system for removing noise from an image by first noise modeling an image signal source to generate noise masks and LUT values characteristic of noise at different frequency levels for each channel, and then applying the stored noise masks and LUT values to an image signal for noise removal. The image is first captured as an electronic image signal by the image signal source, then represented by a pyramid structure whereby each successive level of the pyramid is constructed from DC values of the previous level, and each level of the pyramid corresponds to a different frequency band of the image signal. A Wiener variant filter using DCT transforms is used to filter DCT coefficients at each level. The image is restored with reduced noise by replacing DC values with next level IDCT coefficients then performing an IDCT on the results.

Image noise reduction system using a wiener variant filter in a pyramid

The image processing system of the present invention provides electronic edge detection in keeping with ISO/JPEG/MPEG international compression standards for electronic imaging. Specifically, a novel electronic image processing system for edge detection includes: an image acquisition device for acquiring and representing an image as an electronic image signal; a video memory for storing the image signal; a display for displaying the image signal; a raster to block converter for converting the image signal into block format; a DCT/IDCT processor for transforming the converted signal in accordance with predetermined basis matrices stored in a basis matrix memory; a mask multiplier for generating a mask multiplied signal in accordance with predetermined Laplacian matrices stored in an A matrix memory; a buffer for storing the mask multiplied signal; and a controller for controlling the image processing system in accordance with instructions from a central processing unit (CPU).

System and method for image edge detection using discrete cosine

The present invention is useful in taking images for identification and other purposes without the requirement of a photobooth, regardless of the background of the image. The original background of the 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 for light intensity differences between corresponding pixels of the two images to form a mask differentiating between the foreground and background regions of the image. The mask is then applied to a visible light image of the scene and the preselected background is used to replace the original background.

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Arlington, MA, United States of America

Yibing Yang