: Numerical differential functions.
: Imcalc Tool
: Transendental Algebra.
目次
- thres - threshold TOS at making all pixels less than IP(thres) zero, operates only on real component of complex images.
- lsf - linear sequential (exponential) smoothing filter of TOS
with decay parameter and up/down left right handedness given by
IP(sigma,LR,UD). Useful for fast large scale spatial smoothing. Two applications
give a reasonable approximation to a Gaussian (ie: Central Limit Theorem).
- med - median filter of TOS for 3x3 pixel patch. An edge
preserving noise filter which is particularly effective at removing
salt and pepper (drop-out) noise. Noise is reduced by a (typical)
factor of two and image quantization is unaffected.
- rank - rank order filtering of TOS with pixel region IP(range)
and expected grey level noise level of IP(const).
Useful for allowing parametric statistical measures to be applied to
non-parametric image data. The resulting image has approximately
bi-nomial noise characteristics which can be transformed to a
domain of random uniform errors via the asin mapping.
- gauss - gaussian filter of TOS image with standard deviation
and convolution area of IP( sigma, range). An optimally compact (spatial/frequency) noise filter. Generally used for band-pass filtering and to
reduce noise (particularly the effects of data quantization) before
derivative estimation. Errors are generally reduced by an (approximate)
factor of two.
- tsmooth - local smoothed average of TOS image along direction of minimum gradient. An edge preserving noise filter which reduces image
noise by a factor of (approximately)
(see Tina memo 2003-007).
: Numerical differential functions.
: Imcalc Tool
: Transendental Algebra.
目次
root
平成24年2月7日