diff --git a/pipi/filter/blur.c b/pipi/filter/blur.c
index e2455e3..d97107f 100644
--- a/pipi/filter/blur.c
+++ b/pipi/filter/blur.c
@@ -39,7 +39,7 @@ pipi_image_t *pipi_gaussian_blur_ext(pipi_image_t *src, float rx, float ry,
     pipi_pixels_t *srcp, *dstp;
     float *srcdata, *dstdata;
     double *kernel, *buffer;
-    double K, L;
+    double K;
     int x, y, i, w, h, kr, kw;
 
     w = src->w;
@@ -56,12 +56,11 @@ pipi_image_t *pipi_gaussian_blur_ext(pipi_image_t *src, float rx, float ry,
 
     kr = (int)(3. * rx + 0.99999);
     kw = 2 * kr + 1;
-    K = 1. / (sqrt(2. * M_PI) * rx);
-    L = -1. / (2. * rx * rx);
+    K = -1. / (2. * rx * rx);
 
     kernel = malloc(kw * sizeof(double));
     for(i = -kr; i <= kr; i++)
-        kernel[i + kr] = exp(L * ((double)i - dx) * ((double)i - dx)) * K;
+        kernel[i + kr] = exp(K * ((double)i - dx) * ((double)i - dx));
 
     for(y = 0; y < h; y++)
     {
@@ -94,12 +93,11 @@ pipi_image_t *pipi_gaussian_blur_ext(pipi_image_t *src, float rx, float ry,
 
     kr = (int)(3. * ry + 0.99999);
     kw = 2 * kr + 1;
-    K = 1. / (sqrt(2. * M_PI) * ry);
-    L = -1. / (2. * ry * ry);
+    K = -1. / (2. * ry * ry);
 
     kernel = malloc(kw * sizeof(double));
     for(i = -kr; i <= kr; i++)
-        kernel[i + kr] = exp(L * ((double)i - dy) * ((double)i - dy)) * K;
+        kernel[i + kr] = exp(K * ((double)i - dy) * ((double)i - dy));
 
     for(y = 0; y < h; y++)
     {