boxfilter
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Fast convolve (average) for uniform, rectangular masks. | Fast convolve (average) for uniform, rectangular masks. | ||
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| − | Arguments: | + | Arguments: any three dimensional numeric array, a two dimensional box size and an ignore value |
Return Value: a float numeric array the x and y dimensios and organization of the original with convolved data. | Return Value: a float numeric array the x and y dimensios and organization of the original with convolved data. | ||
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The size can be either a size in x and y defining a rectangle or a square of side length of 'size'. | The size can be either a size in x and y defining a rectangle or a square of side length of 'size'. | ||
| − | Pixels containing the ignore value will be filled in if they are within one half of a box length from a pixel that has a valid value. | + | Pixels containing the ignore value will be filled in with convolved values if they are within one half of a box length from a pixel that has a valid value. |
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| + | boxfilter() will only convolve in the x-y plane. | ||
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| + | You can specify either an x and y for rectangular windows, or just size for a square window. Returns windowed average for all non-ignore pixels. | ||
| + | If you specify verbose, it will return a structure containing the windowed mean, pixel count and standard deviation under the window (plus some other stuff for working with running sums). | ||
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| + | Note: boxfilter() can use 24 bytes of memory per input pixel. It uses a LOT of memory and may exceed RAM limits if used on large objects. Use [[convolve]], [[thm.convolve]] or [[rboxfilter]] for large arrays. | ||
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dv> a | dv> a | ||
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| + | *[[convolve]] | ||
| + | *[[thm.convolve]] | ||
| + | *[[filterx]] | ||
| + | *[[filtery]] | ||
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Revision as of 15:52, 20 February 2006
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Contents: Description, Arguments, Usage, Examples, Images, Related Functions Supported Under Version: >1.69 Current Davinci Version: 2.27 64-bit Safe: Yes
Description Fast convolve (average) for uniform, rectangular masks.
Arguments and Return Values Arguments: any three dimensional numeric array, a two dimensional box size and an ignore value Return Value: a float numeric array the x and y dimensios and organization of the original with convolved data.
Usage Syntax: boxfilter(obj, size, ignore, verbose) The size can be either a size in x and y defining a rectangle or a square of side length of 'size'. Pixels containing the ignore value will be filled in with convolved values if they are within one half of a box length from a pixel that has a valid value. boxfilter() will only convolve in the x-y plane. You can specify either an x and y for rectangular windows, or just size for a square window. Returns windowed average for all non-ignore pixels. If you specify verbose, it will return a structure containing the windowed mean, pixel count and standard deviation under the window (plus some other stuff for working with running sums). Note: boxfilter() can use 24 bytes of memory per input pixel. It uses a LOT of memory and may exceed RAM limits if used on large objects. Use convolve, thm.convolve or rboxfilter for large arrays.
Examples dv> a 345x600x1 array of byte, bsq format [207,000 bytes] dv> bx=boxfilter(a,x=21,y=1,ignore=0) 345x600x1 array of float, bsq format [828,000 bytes] dv> by=boxfilter(a,x=1,y=21,ignore=0) 345x600x1 array of float, bsq format [828,000 bytes] dv> bboth=boxfilter(a,size=21,ignore=0) 345x600x1 array of float, bsq format [828,000 bytes]
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Recent Core Changes Modified On: 07-06-2009 |
