Sigma Delta quantization for images
AssigneeBoard of Trustees of Michigan State University
InventorsRongrong Wang, He Lyu
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Abstract
A technique is presented for quantizing pixels of an image using Sigma Delta quantization. In one aspect, pixel values for an image are segmented into columns of pixel values; and for each column in the matrix, pixel values of a given column are quantized using sigma delta modulation. The pixel values in a given column are preferably quantized as a whole, thereby minimizing accumulated quantization error from a starting pixel value in the given column to a current pixel value in the given column. In another aspect, the pixels of an image are quantized using a 2D generalization of Sigma Delta modulation.
Claims10
A method for quantizing pixels of an image, comprising:
- receiving, by a sequencing circuit, pixel values for an image captured by a camera, where the pixel values are arranged in a matrix;
- grouping, by the sequencing circuit, the pixel values of the matrix into columns of pixel values;
- for each column in the matrix, quantizing, by an analog to digital converter, pixel values of a given column as a whole using sigma delta modulation thereby minimizing accumulated quantization error for the given column from a starting pixel value in the given column to a current pixel value in the given column;
- and
- reconstructing a final image from the quantized pixel values of the matrix using a decoder, where the decoder is configured to minimize an image norm subject to a quantization constraint and the quantization constraint is defined by a finite integration operator applied to a quantization error with an L-infinite norm bounded by half of the quantization step-size, wherein the quantization error is a vector such that each element of the vector contains a quantization error for a given pixel in the matrix.
An imaging system, comprising:
- a camera configured to capture an image of a scene, where the image is represented by pixel values arranged in a matrix;
- a sequencing circuit configured to receive the image from the camera and operates to grouping the pixel values of the matrix into columns of pixel values;
- and
- an analog to digital converter interfaced with the sequencing circuit and, for each column in the matrix, quantizes pixel values of a given column as a whole using sigma delta modulation, thereby minimizing accumulated quantization error for the given column from a starting pixel value in the given column to a current pixel value in the given column;
- and
- a decoder configured to receive the quantized pixel values of the matrix and reconstructing a final image from the quantized pixel values of the matrix, where the decoder minimizes an image norm subject to a quantization constraint and the quantization constraint is defined by a finite integration operator applied to a quantization error with an L-infinite norm bounded by half of the quantization step-size, and the quantization error is a vector such that each element of the vector contains a quantization error for a given pixel in the matrix.
A method for quantizing pixels of an image, comprising:
- receiving, by a sequencing circuit, pixel values for an image captured by a camera, where the pixel values are arranged in a matrix;
- grouping, by the sequencing circuit, the pixel values of the matrix into columns of pixel values;
- for each column in the matrix, quantizing, by an analog to digital converter, pixel values of a given column as a whole using sigma delta modulation thereby minimizing accumulated quantization error for the given column from a starting pixel value in the given column to a current pixel value in the given column;
- and
- reconstructing, by a decoder, a final image from the quantized pixel values of the matrix while minimizing a norm subject to a quantization constraint, where the quantization constraint is defined by a finite integration operator applied to a quantization error with an L-infinite norm bounded by half of the quantization step-size, and the quantization error is a vector such that each element of the vector contains a quantization error for a given pixel in the matrix.
Dependencies are inferred from the claim text.