Image processing apparatus and method and image display apparatus
AssigneeMitsubishi Electric Corporation
InventorsToshiaki Kubo, Satoshi Yamanaka
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Abstract
An image processing apparatus receives n-bit image data, carries out an α-bit bit extension, and outputs (n+α)-bit image data, where n and α are positive integers. The apparatus also performs an epsilon filtering operation that uses the additional gray levels provided by the bit extension to smooth out false edges caused by the bit extension without smoothing out real edges. The output image preserves both the smoothness of regions of gradual change and the sharpness of abrupt changes in the input image.
Claims14
An image processing apparatus comprising:
- a bit extender that receives n-bit image data, carries out an α-bit bit extension, and outputs resultant basic (n+α)-bit image data, n and α being positive integers;
- and
- an edge-preserving smoothing filter for smoothing the basic (n+α)-bit image data by using additional gray levels provided by the bit extension,
- wherein the edge-preserving smoothing filter is an epsilon filter having a threshold value ε equal to 2α.
An image display apparatus comprising:
- a receiver for receiving an analog image signal and converting the analog image signal to n-bit image data, n being a positive integer;
- a bit extender for receiving the n-bit image data, performing an α-bit bit extension, and outputting resultant basic (n+α)-bit image data, α being a positive integer;
- an edge-preserving smoothing filter for smoothing the basic (n+α)-bit image data by using additional gray levels provided by the bit extension to generate smoothed (n+α)-bit image data;
- and
- a display unit for displaying the smoothed (n+α)-bit image data, wherein the edge-preserving smoothing filter is an epsilon filter having a threshold value ε equal to 2α.
An image processing method comprising:
- receiving n-bit image data by utilizing an edge-preserving smoothing filter having a threshold value ε equal to 2α, the smoothing filter performing an α-bit bit extension, and outputting resultant basic (n+α)-bit image data, n and α being positive integers;
- holding and simultaneously outputting the basic (n+α)-bit image data for a plurality of consecutive pixels;
- generating difference data indicating differences between the simultaneously output basic (n+α)-bit image data and the basic (n+α)-bit image data of a pixel of interest;
- generating decision data indicating whether the difference data are greater than the threshold value ε;
- generating a weighted average value of the difference data conditional on the decision data;
- and
- adding the basic (n+α)-bit image data of the pixel of interest to the weighted average value data.
An image processing apparatus comprising a bit-extending edge-preserving smoothing filter that receives n-bit image data, carries out an α-bit bit extension, and outputs resultant (n+α)-bit image data, n and α being positive integers,
- wherein the bit-extending edge-preserving smoothing filter comprises a bit-extending epsilon filter having a threshold value ε equal to 2α.
An image processing method comprising:
- receiving n-bit image data, performing an α-bit bit extension, and outputting resultant basic (n+α)-bit image data, n and a being positive integers;
- holding and simultaneously outputting the basic (n+α)-bit image data for pixels in a two-dimensional region having a horizontal width of h pixels and a vertical height of v pixels, h and v both being positive integers equal to or greater than 2α;
- generating difference data indicating differences between the basic (n+α)-bit image data for pixels in said two-dimensional region and the basic (n+α)-bit image data of a pixel of interest;
- generating decision data indicating whether the difference data are greater than a threshold value ε;
- generating a weighted average value of the difference data conditional on the decision data;
- and
- adding the basic (n+α)-bit image data of the pixel of interest to the weighted average value data.
Dependencies are inferred from the claim text.