Fast repeated integral images
AssigneeQUALCOMM Incorporated
InventorsMing-Chang Tsai, Pawan K. Baheti, Murali R. Chari, Raghuraman Krishnamoorthi
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Abstract
A repeated integral images method filters image data in only two passes, e.g., the first pass filters horizontal rows of pixels and a second pass filters vertical columns of pixels, or in a single pass. The filter performs at least one infinite impulse response (IIR) filter and at least one finite impulse response (FIR) filter on the image data. A plurality of IIR filters and FIR filters maybe performed to approximate a Gaussian filter. By minimizing the number of passes, the data flow between the processing unit and the storage unit is greatly reduced compared to conventional repeated integral images method thereby improving computation time.
Claims52
A method of filtering an image comprising:
- receiving image data comprising an array of pixels;
- performing at least one infinite impulse response (IIR) filter and at least one finite impulse response (FIR) filter on a first plurality of lines of pixels in the image data that extends in a first direction;
- performing at least one IIR filter and at least one FIR filter on a second plurality of lines of pixels that extends in a second direction that is different than the first direction to produce a filtered image data;
- and
- storing the filtered image data.
An apparatus comprising:
- storage unit for storing image data;
- a data bus coupled to the storage unit;
- a fast repeated integral images filter coupled to the storage unit through the data bus, the fast repeated integral images filter comprising:
- at least one infinite impulse response (IIR) filter;
- and
- at least one finite impulse response (FIR) filter coupled to the at least one IIR filter;
- wherein the fast repeated integral images filter is adapted to receive the image data from the storage unit through the data bus, and to filter a plurality of lines of pixels in the image data that extends in a first direction with the at least one IIR filter and the at least one FIR filter and to filter a second plurality of lines of pixels that extends in a second direction that is different than the first direction to produce a filtered image data and to output the filtered image data to the storage unit through the data bus.
An apparatus comprising:
- means for receiving image data comprising an array of pixels;
- means for performing at least one infinite impulse response (IIR) filter and at least one finite impulse response (FIR) filter on a first plurality of lines of pixels in the image data that extends in a first direction;
- means for performing at least one IIR filter and at least one FIR filter on a second plurality of lines of pixels that extends in a second direction that is different than the first direction to produce a filtered image data;
- and
- means for storing the filtered image data.
A computer-readable medium including program code stored thereon, comprising:
- program code to receive image data comprising an array of pixels;
- program code to perform at least one infinite impulse response (IIR) filter and at least one finite impulse response (FIR) filter on a first plurality of lines of pixels in image data that extends in a first direction;
- program code to perform at least one IIR filter and at least one FIR filter on a second plurality of lines of pixels that extends in a second direction to produce a filtered image data, the second direction being different than the first direction;
- and
- program code to store the filtered image data.
Dependencies are inferred from the claim text.