Apparatus and method for quantizing and/or reconstructing multi-dimensional digital image signals
AssigneeEastman Kodak Company
InventorJohn A. Weldy
Life of this patent
Estimating the term…
Abstract
The method and apparatus of the present invention performs the quantization, sampling, and final digital image signal reconstruction in a way that reduces quantization artifacts such as contouring while retaining desired spatial (temporal) frequency response and resolution. The technique of the present invention features a spatially varying quantization step, a low pass filtering step, a second spatially varying quantization step, and a comparison step to determine the reconstructed signal.
Claims21
A method for quantizing multi-dimensional digital image signals comprising the steps of:
- a) forming a multi-leveled quantized digital image signal;
- b) reducing the number of quantization levels by further quantizing, in a spatially varying manner, the quantized digital image signal of step a) by selecting quantizers based upon the sample location indices value of each image pixel represented by said digital image signals, wherein each coordinate of each image pixel is a sample location indice value and by applying the quantized digital image signal to the selected quantizers;
- c) storing and/or transmitting the digital image signal resulting from step b);
- d) retrieving the digital image signal resulting from step c);
- and
- e) reconstructing the digital image from step d) in a manner that increases the number of levels in the digital image signal.
An apparatus for quantizing multi-dimensional digital image signals comprising:
- a plurality of quantizing means each having a plurality of steps, for receiving a multi-level quantized image signal and for reducing the number of quantization levels by further quantizing said multi-level quantized image signal, in a spatially varying manner;
- means for selecting quantizers from said plurality of quantizing means based upon the sample location indices value of each image pixel represented by said digital image signals, wherein the coordinate of each image pixel is a sample location indicia value
- means for receiving an output from said selected quantizing means and for storing and/or transmitting a digital image signal with a reduced number of quantization levels;
- means for retrieving said stored and/or transmitted digital image signal;
- and
- means for reconstructing said retrieved digital image signal to a larger number of quantization levels.
Dependencies are inferred from the claim text.