im_abs - finds the absolute value or the magnitude of an image
#include <vips/vips.h>
int im_abs( in, out )
IMAGE *in, *out;
im_abs(3) finds the absolute value of an image. Copy for UNSIGNED
types, negate for int types, fabs(3) for float types, and calculate
modulus for complex types. Any size, any number of bands.
The function returns 0 on success and -1 on error.
im_exp10tra(3), im_sign(3)
25 April 1991