| .TH IM_CONTRAST_SURFACE 3 "01 May 2006" |
| .SH NAME |
| im_contrast_surface, im_contrast_surface_raw \- Generate contrast surface |
| .SH SYNOPSIS |
| .nf |
| .B #include <vips/vips.h> |
| .sp |
| .BI "int im_contrast_surface( IMAGE " "*in" ", IMAGE " "*out" ", int " "half_win_size" ", int " "spacing" " ); |
| .br |
| |
| .BI "int im_contrast_surface_raw( IMAGE " "*in" ", IMAGE " "*out" ", int " "half_win_size" ", int " "spacing" " ); |
| .fi |
| .SH DESCRIPTION |
| These functions generate an image where the value of each pixel represents the |
| contrast within a square window of size 2 * half_win_size + 1 centred on the |
| corresponsing point in the input image. |
| .PP |
| The output is sub-sampled by a factor of spacing. |
| .PP |
| Input must be single-band uncoded uchar, WIO or PIO. |
| .PP |
| Output is single-band uncoded uint, WIO or PIO. |
| .PP |
| In |
| .BR im_contrast_surface(3) , |
| pixels beyond the edges of the input image are considered to be have the value |
| of the nearest pixel which is in the image. |
| .PP |
| Alternatively, in |
| .BR im_contrast_surface_raw(3) , |
| pixels within half_win_size of the edge are not calculated, and output is |
| smaller accordingly. |
| .SH RETURN VALUE |
| The functions returns 0 on success and -1 on error. |
| .SH COPYRIGHT |
| .br |
| Copyright 2006, The Nottingham Trent University. |
| .SH AUTHOR |
| Tom Vajzovic |
| |
