Method and apparatus of adaptive interpolation based on edge detection

An interpolation method for generating a target pixel at a target location within a video image, the method comprising:

• generating a plurality of measurement values, each of the measurement values corresponding to an edge direction and being generated according to a corresponding first pixel set and a corresponding second pixel set, wherein the first pixel set comprises at least a first pixel, the second pixel set comprises at least a second pixel, and the first pixel and the second pixel reside on opposite sides of the target location along the corresponding edge direction;
• identifying a minimum measurement value from the plurality of measurement values, and
• calculating a value of the target pixel according to pixels of the first and second pixel sets which correspond to the minimum measurement value;
• wherein when the minimum measurement value corresponds to a plurality of edge directions, the method further comprises:
• defining a detecting direction based on the target location, the detecting direction forming a plurality of acute angles with the plurality of edge directions corresponding to the minimum measurement value;
• and
• selecting a first pixel set and a second pixel set from one of the plurality of edge directions corresponding to the minimum angle of the plurality of acute angles in order to calculate the value of the target pixel;
• wherein the detecting direction is the vertical direction of the target location, and when the minimum acute angle simultaneously corresponds to a first edge direction and a second edge direction, the method further comprises:
• comparing the difference between an old direction and the first edge direction with the difference between the old direction and the second edge directions to select a first pixel set and a second pixel set from one of the first and second edge directions according to the comparison result in order to calculate the value of the target pixel, wherein the old direction corresponds to the first and second pixel sets being employed when calculating a previous target pixel.

An interpolation device for generating a target pixel at a target location within a video image, the interpolation device comprising:

• a measuring circuit for generating a plurality of measurement values, wherein each measurement value corresponds to an edge direction and represents a measure of variance between a plurality of pixels which correspond to the edge direction and are on opposite sides of the target location;
• an analysis circuit coupled to the measuring circuit for generating a reference value based on the pixels corresponding to a minimum measurement value and for generating a weight factor according to the minimum measurement value and at least one threshold value;
• and
• an interpolating circuit coupled to the analysis circuit for generating the target pixel according to a weighted operation of the reference value based on the weight factor.