From images to scalars

Within DIPlib all data, i.e. multi-dimensional data, such as images, and scalar, are all represented by the same object: the image. Scalars are stored as zero dimensional images. Examine, for example, the following code to compute the sum over all the grey values:

dip_Image img;
dip_Image value;
...
dip_Sum ( img, 0, value, 0 );

Which stores the sum over all the pixel values of img in the 0-D image value. We often want to directly manipulate scalars, in which case we need to extract the value. This can be accomplished easily with the GetInteger, GetFloat or the GetComplex functions:

dip_Image img;
dip_Image valueimg;
dip_float value;
...
dip_Sum ( img, 0, valueimg, 0 );
dip_GetFloat ( valueimg, &value, 0 );
printf ( "The sum is: %f\n", value );