Polaroid Corporation

Lon E Sunshine

Munib A Wober

Michael L Reisch

Ibrahim Hajjahmad

Yibing Yang

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

An image processing system for sample rate conversion of an image signal representing an image of pixels from a first sample rate to a second sample rate includes: an image acquisition device for acquiring the image signal from an image signal source at the first sample rate; a first memory for buffering the input signal; a second memory for storing predetermined discrete cosine transform coefficients; a dot product multiplier for multiplying the image signal retrieved from the first memory times the predetermined coefficients to produce an output signal at the second sampling rate; a third memory for buffering the output signal; control sequencer logic for controlling operation of the image processing system; and an output device for providing a resampled image at the second sampling rate from the output signal. The image processing system facilitates sample rate conversion by segmenting the image into segments of image data points wherein a separate and different offset is determined for each segment. A discrete cosine transform is performed on each segment of image data points to generate corresponding DCT coefficients. Thereafter, resampled image data points are generated by taking a modified IDCT of the DCT coefficients using a modified IDCT basis matrix which is dependent upon a sampling rate conversion ratio and/or an offset.

System and method for sample rate conversion of an image using discrete

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.

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Boston, MA, United States of America

Lon E Sunshine