Add helper function for kernel normalization

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
This commit is contained in:
Yuxuan Shui 2019-02-20 01:46:54 +00:00
parent a5e3837f6d
commit ed9c7064de
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GPG Key ID: 37C999F617EA1A47
2 changed files with 27 additions and 0 deletions

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@ -121,4 +121,24 @@ void sum_kernel_preprocess(conv *map) {
}
}
/**
* Normalize a convolution kernel.
*
* @param[in,out] kern the kernel
*/
void normalize_conv_kern(conv *kern) {
double sum = 0.0;
for (int i = 0; i < kern->w * kern->h; i++) {
sum += kern->data[i];
}
double factor = 1.0 / sum;
for (int i = 0; i < kern->w * kern->h; i++) {
kern->data[i] *= factor;
}
if (kern->rsum) {
free(kern->rsum);
kern->rsum = NULL;
}
}
// vim: set noet sw=8 ts=8 :

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@ -25,6 +25,13 @@ conv *gaussian_kernel(double r);
/// shadow_sum[x*d+y] is the sum of the kernel from (0, 0) to (x, y), inclusive
void sum_kernel_preprocess(conv *map);
/**
* Normalize a convolution kernel.
*
* @param[in,out] kern the kernel
*/
void normalize_conv_kern(conv *kern);
static inline void free_conv(conv *k) {
free(k->rsum);
free(k);