diff --git a/src/image.c b/src/image.c
index 52093285..2811cb37 100644
--- a/src/image.c
+++ b/src/image.c
@@ -494,6 +494,16 @@ image grayscale_image(image im)
     return gray;
 }
 
+image threshold_image(image im, float thresh)
+{
+    int i;
+    image t = make_image(im.w, im.h, im.c);
+    for(i = 0; i < im.w*im.h*im.c; ++i){
+        t.data[i] = im.data[i]>0 ? 1 : 0;
+    }
+    return t;
+}
+
 image blend_image(image fore, image back, float alpha)
 {
     assert(fore.w == back.w && fore.h == back.h && fore.c == back.c);
diff --git a/src/image.h b/src/image.h
index 27dc62a7..e16d2854 100644
--- a/src/image.h
+++ b/src/image.h
@@ -35,7 +35,9 @@ void saturate_exposure_image(image im, float sat, float exposure);
 void hsv_to_rgb(image im);
 void rgbgr_image(image im);
 void constrain_image(image im);
+
 image grayscale_image(image im);
+image threshold_image(image im, float thresh);
 
 image collapse_image_layers(image source, int border);
 image collapse_images_horz(image *ims, int n);
diff --git a/src/writing.c b/src/writing.c
index 7c23db12..02d3fcce 100644
--- a/src/writing.c
+++ b/src/writing.c
@@ -102,6 +102,10 @@ void test_writing(char *cfgfile, char *weightfile, char *outfile)
     printf("%s: Predicted in %f seconds.\n", filename, sec(clock()-time));
     image pred = get_network_image(net);
 
+    image t = threshold_image(pred, .2);
+    free_image(pred);
+    pred = t;
+
     if (outfile) {
         printf("Save image as %s.png (shape: %d %d)\n", outfile, pred.w, pred.h);
         save_image(pred, outfile);