Patent ID: 7151858

Claim:
An apparatus for correcting the edge of an input image, the apparatus comprising: an edge detector which outputs an image signal by performing a multi-stage Haar Wavelet transform on the input image, wherein the output image signal comprises edge data of the input image, the edge detector comprising: a Haar Wavelet transformer that performs the multi-stage Haar Wavelet transform in at least three stages without causing down sampling thereof, the image signal outputted by the multi-stage Haar Wavelet transform being divided into first, second, third and fourth sub-bands, a horizontal coefficient detector for detecting a horizontal coefficient of the image signal by performing a first operation on a transform coefficients obtained through the multi-stage Haar Wavelet transform, the first operation comprising: receiving a first transform coefficient having units of pixels, the first transform coefficient being generated from third sub-band having a high frequency in a vertical direction and a low frequency in a horizontal direction, the first transform coefficient being obtained by a first stage of the multi-stage Haar Wavelet transform, receiving a second transform coefficient having units of pixels, the second transform coefficient being generated from third sub-band having a high frequency in a vertical direction and a low frequency in a horizontal direction, the second transform coefficient being obtained by a second stage of the multi-stage Haar Wavelet transform, receiving a third transform coefficient having units of pixels, the third transform coefficient being generated from third sub-band having a high frequency in a vertical direction and a low frequency in a horizontal direction, the third transform coefficient being obtained by a third stage of the multi-stage Haar Wavelet transform, generating horizontal coefficients by multiplying the first transform coefficient and the third transform coefficient and adding the second coefficient to the result of the multiplication, outputting the horizontal coefficient of the image signal, a vertical coefficient detector for detecting a vertical coefficient of the image signal by performing a second operation on the transform coefficient obtained through the multi-stage Haar Wavelet transform; and an adder for adding the horizontal and vertical coefficients so as to measure a 2-D coefficient, and outputting the 2-D coefficient as edge data; a gain detector which detects a gain for correcting the edge of the input image by normalizing the edge data at a position to be corrected, wherein the edge data is obtained from the image signal output from the edge detector; a pixel value detector for detecting a corrected pixel value regarding the edge data at a position to be corrected by performing an operation on the edge data to be corrected, at least one pixel adjacent to the edge data, and the gain; and an image signal generator for generating an image whose edge is formed based on the corrected pixels.