| .TH IM_MEASURE 3 "24 October 1992" |
| .SH NAME |
| im_measure \- measure colour patches off images |
| .SH SYNOPSIS |
| #include <vips/vips.h> |
| |
| DOUBLEMASK *im_measure(in, box, h, v, sel, nsel, name) |
| .br |
| IMAGE *in; |
| .br |
| IMAGE_BOX *box; |
| .br |
| int h, v; |
| .br |
| int *sel; |
| .br |
| int nsel; |
| .br |
| char *name; |
| |
| .SH DESCRIPTION |
| Analyse a grid of colour patches, producing a DOUBLEMASK of averages. |
| Pass an IMAGE, an IMAGE_BOX, the number of horizontal and vertical |
| patches, an array giving the numbers of the patches to measure (patches |
| are numbered left-to-right, top-to-bottom, starting with 1) and the name we |
| should give the output mask. Return a DOUBLEMASK in which rows are patches and |
| columns are bands. Only the central 50% of each patch is averaged. |
| |
| Example: 6 band image of 4x2 block of colour patches. |
| |
| +---+---+---+---+ |
| | 1 | 2 | 3 | 4 | |
| +---+---+---+---+ |
| | 5 | 6 | 7 | 8 | |
| +---+---+---+---+ |
| |
| Then call im_measure( im, box, 4, 2, { 2, 4 }, 2, "fred" ) makes a mask |
| "fred" which has 6 columns, two rows. The first row contains the averages |
| for patch 2, the second for patch 4. |
| |
| Output warnings: a warning is issued if the standard deviation of any patch is |
| greater than 20% of the mean of that patch. |
| |
| .SH RETURN VALUE |
| NULL on error. |
| .SH SEE ALSO |
| im_avg(3), im_deviate(3), im_stats(3). |
