int im_gammacorrect(in, out, exponent)
IMAGE *in, *out;
DESCRIPTIONim_gammacorrect performs gamma correction to in. The result in written in out. The correction is carried out by creating a lookup table using the double exponent and mapping in through it. The exponent is applied on a ramp lut and the resultant lut is scaled. All channels of im are mapped through the lookup table.
AUTHORN. Dessipris - 10/05/1991