Calculate weights for image pixels based on image gradient

calculates
the pixel weight for each pixel in image `W`

= gradientweight(`I`

)`I`

based
on the gradient magnitude at that pixel, and returns the weight array `W`

.
The weight of a pixel is inversely related to the gradient values
at the pixel location. Pixels with small gradient magnitude (smooth
regions) have a large weight and pixels with large gradient magnitude
(such as on the edges) have a small weight.

returns
the weight array `W`

= gradientweight(___,`Name,Value`

)`W`

using name-value pairs to
control aspects of weight computation.

`gradientweight`

uses double-precision floating point operations for internal computations for all classes of`I`

, except when`I`

is of class`single`

, in which case`gradientweight`

uses single-precision floating point operations internally.