Method and apparatus for finding areas of interest in images

An apparatus for finding an area of interest in an input image, comprising:

• (a) filtering means for filtering said input image with a filter to generate a filtered image, wherein at least part of the filter is applied to each entire row of the input image before any part of the filter is applied to any pixels of the next row of the input image;
• (b) first determining means for determining the location of an artifact in said filtered image;
• and
• (c) second determining means for determining the location of said area of interest in said input image according to said location of said artifact in said filtered image, wherein the filtering means comprises:
• (1) a (4.times.4) compression filter for filtering the input to generate a first compressed image, wherein at least part of the (4.times.4) compression filter is applied to each entire row of the input image before any part of the (4.times.4) compression filter is applied to any pixels of the next row of the input image:
• (2) a first (2.times.2) compression filter for filtering the first compressed image to generate a second compressed image, wherein at least part of the first (2.times.2) compression filter is applied to each entire row of the first compressed image before any part of the first (2.times.2) compression filter is applied to any pixels of the next row of the first compressed image
• (3) a second (2.times.2) compression filter for filtering the second compressed image to generate a third compressed image, wherein at least part of the second (2.times.2) compression filter is applied to each entire row of the second compressed image before any part of the second (2.times.2) compression filter is applied to any pixels of the next row of the second compressed image;
• and
• (4) a third (2.times.2) compression filter for optionally filtering the third compressed image to generate a fourth compressed image, wherein at least part of the third (2.times.2) compression filter is applied to each entire row of the third compressed image before any part of the third (2.times.2) compression filter is applied to any pixels of the next row of the third compressed image, wherein:
• the first (2.times.2) compression filter is applied to at least part of the first compressed image before the (4.times.4) compression filter is completely applied to the input image;
• the second (2.times.2) compression filter is applied to at least part of the second compressed image before the first (2.times.2) compression filter is completely applied to the first compressed image;
• the third (2.times.2) compression filter is optionally applied to at least part of the third compressed image before the second (2.times.2) compression filter is completely applied to the second compressed image;
• and
• if the third (2.times.2) compression filter is applied, then the filtered image comprises the fourth compressed image;
• otherwise, the filtered image comprises the third compressed image.

An apparatus for filtering an input image, comprising:

• (a) a (1.times.4) filter for receiving a plurality of pixels from the input image one row at a time and for filtering the pixels, the (1.times.4) filter having a first scale factor;
• (b) a linear (1.times.4) buffer for receiving and temporarily storing filtered pixels from the (1.times.4) filter;
• (c) a (2.times.4) filter for receiving filtered pixels from the (1.times.4) filter and the (1.times.4) buffer and for further filtering the filtered pixels, the (2.times.4) filter having a second scale factor different from the first scale factor;
• (d) a linear (2.times.4) buffer for receiving and temporarily storing the filtered pixels from the (2.times.4) filter;
• (e) a (4.times.4) filter for receiving filtered pixels from the (1.times.4) filter, the (1.times.4) buffer, and the (2.times.4) buffer and for further filtering the filtered pixels, the (4.times.4) filter having a third scale factor different from the first scale factor and different from the second scale factor;
• (f) a first (1.times.2) filter for receiving the filtered pixels from the (4.times.4) filter and for further filtering the filtered pixels, the first (1.times.2) filter having a fourth scale factor;
• (g) a first linear (1.times.2) buffer for receiving and temporarily storing filtered pixels from the first (1.times.2) filter;
• (h) a first (2.times.2) filter for receiving filtered pixels from the first (1.times.2) filter and the first (1.times.2) buffer and for further filtering the filtered pixels, the first (2.times.2) filter having a fifth scale factor different from the fourth scale factor;
• (i) a second (1.times.2) filter for receiving the filtered pixels from the first (2.times.2) filter and for further filtering the filtered pixels, the second (1.times.2) filter having the fourth scale factor;
• (j) a second linear (1.times.2) buffer for receiving and temporarily storing filtered pixels from the second (1.times.2) filter;
• (k) a second (2.times.2) filter for receiving filtered pixels from the second (1.times.2) filter and the second (1.times.2) buffer and for further filtering the filtered pixels, the second (2.times.2) filter having the fifth scale factor;
• (l) a third (1.times.2) filter for optionally receiving the filtered pixels from the second (2.times.2) filter and for optionally further filtering the filtered pixels, the third (1.times.2) filter having the fourth scale factor;
• (m) a third linear (1.times.2) buffer for optionally receiving and optionally temporarily storing filtered pixels from the third (1.times.2) filter;
• and
• (k) a third (2.times.2) filter for optionally receiving filtered pixels from the third (1.times.2) filter and the third (1.times.2) buffer and for optionally further filtering the filtered pixels, the third (2.times.2) filter having the fifth scale factor.