diff --git a/imgproc.c b/imgproc.c
index 852b25d..4c1352a 100644
--- a/imgproc.c
+++ b/imgproc.c
@@ -613,92 +613,39 @@ double iterative_threshold(Imlib_Image *source_image, double thresh,
   return new_thresh * 100;
 }
 
-/* get minimum lum value */
-double get_minval(Imlib_Image *source_image, int x, int y, int w, int h,
-                 luminance_t lt)
+/* get minimum and maximum lum values */
+void get_minmaxval(Imlib_Image *source_image, luminance_t lt,
+                   double *min, double *max)
 {
   Imlib_Image current_image; /* save image pointer */
-  int height, width; /* image dimensions */
+  int w, h; /* image dimensions */
   int xi,yi; /* iteration variables */
   Imlib_Color color; /* Imlib2 RGBA color structure */
-  int minval = MAXRGB;
   int lum = 0;
 
+  *min = MAXRGB;
+  *max = 0;
+
   /* save pointer to current image */
   current_image = imlib_context_get_image();
 
   /* get image dimensions */
   imlib_context_set_image(*source_image);
-  height = imlib_image_get_height();
-  width = imlib_image_get_width();
-
-  /* special value -1 for width or height means image width/height */
-  if(w == -1) w = width;
-  if(h == -1) h = width;
-
-  /* assure valid coordinates */
-  if(x+w > width) x = width-w;
-  if(y+h > height) y = height-h;
-  if(x<0) x=0;
-  if(y<0) y=0;
+  h = imlib_image_get_height();
+  w = imlib_image_get_width();
 
   /* find the minimum value in the image */
-  for(xi=0; (xi<w) && (xi<width); xi++) {
-    for(yi=0; (yi<h) && (yi<height); yi++) {
+  for(xi=0; xi<w; xi++) {
+    for(yi=0; yi<h; yi++) {
       imlib_image_query_pixel(xi, yi, &color);
       lum = clip(get_lum(&color, lt),0,255);
-      if(lum < minval) minval = lum;
+      if(lum < *min) *min = lum;
+      if(lum > *max) *max = lum;
     }
   }
 
   /* restore image from before function call */
   imlib_context_set_image(current_image);
-
-  return minval;
-}
-
-/* get maximum luminance value */
-double get_maxval(Imlib_Image *source_image, int x, int y, int w, int h,
-                 luminance_t lt)
-{
-  Imlib_Image current_image; /* save image pointer */
-  int height, width; /* image dimensions */
-  int xi,yi; /* iteration variables */
-  Imlib_Color color; /* Imlib2 RGBA color structure */
-  int lum = 0;
-  int maxval = 0;
-
-  /* save pointer to current image */
-  current_image = imlib_context_get_image();
-
-  /* get image dimensions */
-  imlib_context_set_image(*source_image);
-  height = imlib_image_get_height();
-  width = imlib_image_get_width();
-
-  /* special value -1 for width or height means image width/height */
-  if(w == -1) w = width;
-  if(h == -1) h = width;
-
-  /* assure valid coordinates */
-  if(x+w > width) x = width-w;
-  if(y+h > height) y = height-h;
-  if(x<0) x=0;
-  if(y<0) y=0;
-
-  /* find the minimum value in the image */
-  for(xi=0; (xi<w) && (xi<width); xi++) {
-    for(yi=0; (yi<h) && (yi<height); yi++) {
-      imlib_image_query_pixel(xi, yi, &color);
-      lum = clip(get_lum(&color, lt),0,255);
-      if(lum > maxval) maxval = lum;
-    }
-  }
-
-  /* restore image from before function call */
-  imlib_context_set_image(current_image);
-
-  return maxval;
 }
 
 /* draw a white (background) border around image, overwriting image contents
diff --git a/imgproc.h b/imgproc.h
index fe73167..89a8908 100644
--- a/imgproc.h
+++ b/imgproc.h
@@ -141,13 +141,9 @@ double get_threshold(Imlib_Image *source_image, double fraction, luminance_t lt,
 double iterative_threshold(Imlib_Image *source_image, double thresh,
                            luminance_t lt, int x, int y, int w, int h);
 
-/* get minimum gray value */
-double get_minval(Imlib_Image *source_image, int x, int y, int w, int h,
-                 luminance_t lt);
-
-/* get maximum gray value */
-double get_maxval(Imlib_Image *source_image, int x, int y, int w, int h,
-                 luminance_t lt);
+/* get minimum and maximum gray (luminace) values */
+void get_minmaxval(Imlib_Image *source_image, luminance_t lt,
+                   double *min, double *max);
 
 /* compute luminance from RGB values */
 int get_lum(Imlib_Color *color, luminance_t lt);
diff --git a/ssocr.c b/ssocr.c
index f8fe7e5..5dec665 100644
--- a/ssocr.c
+++ b/ssocr.c
@@ -727,9 +727,10 @@ int main(int argc, char **argv)
 
   /* get minimum and maximum "value" values */
   if((flags & DEBUG_OUTPUT) || (flags & PRINT_INFO)) {
+    double min, max;
+    get_minmaxval(&image, lt, &min, &max);
     fprintf(stderr, "%.2f <= lum <= %.2f (lum should be in [0,255])\n",
-                    get_minval(&image, 0, 0, -1, -1, lt),
-                    get_maxval(&image, 0, 0, -1, -1, lt));
+                    min, max);
   }
 
   /* adapt threshold to image */
@@ -989,8 +990,7 @@ int main(int argc, char **argv)
               fprintf(stderr, " adjusting T1=%.2f and T2=%.2f to image\n",
                               t1, t2);
             }
-            min = get_minval(&image, 0, 0, -1, -1, lt);
-            max = get_maxval(&image, 0, 0, -1, -1, lt);
+            get_minmaxval(&image, lt, &min, &max);
             t1 = min + t1/100.0 * (max - min);
             t2 = min + t2/100.0 * (max - min);
             if(flags & VERBOSE) {
@@ -1046,10 +1046,10 @@ int main(int argc, char **argv)
           }
           /* get minimum and maximum "value" values in cropped image */
           if((flags&DEBUG_OUTPUT) || (flags&PRINT_INFO) || (flags&VERBOSE)) {
+            double min, max;
+            get_minmaxval(&image, lt, &min, &max);
             fprintf(stderr, "  %.2f <= lum <= %.2f in cropped image"
-                            " (lum should be in [0,255])\n",
-                            get_minval(&image, 0, 0, -1, -1, lt),
-                            get_maxval(&image, 0, 0, -1, -1, lt));
+                            " (lum should be in [0,255])\n", min, max);
           }
           /* adapt threshold to cropped image */
           thresh = adapt_threshold(&image, thresh, lt, 0, 0, -1, -1, flags);