US 7,023,487 B1Granted

Deinterlacing of video sources via image feature edge detection

AssigneeSilicon Image, Inc.

InventorDale R. Adams

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Abstract

An interlaced to progressive scan video converter which identifies object edges and directions, and calculates new pixel values based on the edge information. Source image data from a single video field is analyzed to detect object edges and the orientation of those edges. A 2-dimensional array of image elements surrounding each pixel location in the field is high-pass filtered along a number of different rotational vectors, and a null or minimum in the set of filtered data indicates a candidate object edge as well as the direction of that edge. A 2-dimensional array of edge candidates surrounding each pixel location is characterized to invalidate false edges by determining the number of similar and dissimilar edge orientations in the array, and then disqualifying locations which have too many dissimilar or too few similar surrounding edge candidates. The surviving edge candidates are then passed through multiple low-pass and smoothing filters to remove edge detection irregularities and spurious detections, yielding a final edge detection value for each source image pixel location. For pixel locations with a valid edge detection, new pixel data for the progressive output image is calculated by interpolating from source image pixels which are located along the detected edge orientation.

A system for the detection of image feature edges comprising:

a) a lowpass filter responsive to a first, second, third and fourth vertically aligned luma data sample rows and operative to develop a first, second, third and fourth low pass filtered luma data samples;
b) a two-dimensional pixel storage array responsive to the first, second, third and fourth lowpass filtered luma data samples and operative to develop a two-dimensional array of pixel data;
c) a first horizontal halfband highpass filter receptive to the second and third lowpass filtered luma data samples and operative to develop a first horizontal highpass filtered luma data sample;
d) a second horizontal halfband highpass filter receptive to the second and third vertically aligned luma data sample rows and operative to develop a second horizontal highpass filtered luma data sample;
e) a luma maximum/minimum/delta calculation module receptive to the two-dimensional array of pixel data and operative to develop a minimum/maximum/delta;
f) a directional halfband highpass filter array receptive to the two-dimensional array of pixel data and operative to develop a set of directional highpass filter outputs;
g) a first horizontal lowpass filter receptive to the first horizontal highpass filtered luma data sample and operative to develop a first horizontal lowpass filtered luma data sample;
h) a second horizontal lowpass filter receptive to the second horizontal highpass filtered luma data sample and operative to develop a second horizontal lowpass filtered luma data sample;
i) an above/below filter pair output averaging module responsive to the highpass filter outputs and operative to develop a set of pair-averaged filter output magnitudes;
j) an edge maximum/minimum calculation module responsive to the set of pair-averaged filter output magnitudes and operative to develop a too many maximums signal, a minimum-maximum/close signal, an edge minimum signal, a minimum edge threshold signal and a minimums signal;
k) an edge direction calculation module responsive to the minimum/maximum/delta, the set of pair-averaged filter outputs, the maximums signal, the minimum-maximum/close signal, the edge minimum signal, the minimum edge threshold signal, the minimums signal, the first horizontal lowpass filtered luma data sample and the second horizontal lowpass filtered luma data sample and operative to develop an edge direction;
and
l) a post-detection filter array responsive to the edge direction and operative to develop a final edge direction.

10 more elements

Abstract

Claims13