`IM3CONVOLUTION(r;f;i;cr;cg;cb;d)`

applies the convolution filter in the 3×3 matrix `f`

to the RGB image in matrix `r`

; scalar `i`

(default 1) defines the intensity parameter; scalars `cr`

, `cg`

and `cb`

contain 0 or 1 (default) according to whether the red, green and blue channels, respectively, are to be modified. If the “feedback” defined by scalar `d`

is 0 (default), the new value at each point is `i`

multiplied by the sum of the values at the point and nearby points multiplied by the convolution matrix.

Alternatively, if `d`

=i (default), the new value at each point is calculated by taking (1-`i`

) multiplied by the current value at the point, and then subtracting `i`

multiplied by the sum of the values at the point and nearby points multiplied by the values in the convolution matrix.