We do our OWN resizing!

src/darknet.c

@@ -93,6 +93,7 @@ void visualize(char *cfgfile, char *weightfile)
 
 int main(int argc, char **argv)
 {
+    //test_resize(argv[1]);
     //test_convolutional_layer();
     if(argc < 2){
         fprintf(stderr, "usage: %s <function>\n", argv[0]);

src/image.c

@@ -375,105 +375,6 @@ image make_random_kernel(int size, int c, float scale)
     return out;
 }
 
-// Returns a new image that is a cropped version (rectangular cut-out)
-// of the original image.
-IplImage* cropImage(const IplImage *img, const CvRect region)
-{
-    IplImage *imageCropped;
-    CvSize size;
-
-    if (img->width <= 0 || img->height <= 0
-            || region.width <= 0 || region.height <= 0) {
-        //cerr << "ERROR in cropImage(): invalid dimensions." << endl;
-        exit(1);
-    }
-
-    if (img->depth != IPL_DEPTH_8U) {
-        //cerr << "ERROR in cropImage(): image depth is not 8." << endl;
-        exit(1);
-    }
-
-    // Set the desired region of interest.
-    cvSetImageROI((IplImage*)img, region);
-    // Copy region of interest into a new iplImage and return it.
-    size.width = region.width;
-    size.height = region.height;
-    imageCropped = cvCreateImage(size, IPL_DEPTH_8U, img->nChannels);
-    cvCopy(img, imageCropped,NULL);  // Copy just the region.
-
-    return imageCropped;
-}
-
-// Creates a new image copy that is of a desired size. The aspect ratio will
-// be kept constant if 'keepAspectRatio' is true, by cropping undesired parts
-// so that only pixels of the original image are shown, instead of adding
-// extra blank space.
-// Remember to free the new image later.
-IplImage* resizeImage(const IplImage *origImg, int newHeight, int newWidth,
-        int keepAspectRatio)
-{
-    IplImage *outImg = 0;
-    int origWidth = 0;
-    int origHeight = 0;
-    if (origImg) {
-        origWidth = origImg->width;
-        origHeight = origImg->height;
-    }
-    if (newWidth <= 0 || newHeight <= 0 || origImg == 0
-            || origWidth <= 0 || origHeight <= 0) {
-        //cerr << "ERROR: Bad desired image size of " << newWidth
-        //  << "x" << newHeight << " in resizeImage().\n";
-        exit(1);
-    }
-
-    if (keepAspectRatio) {
-        // Resize the image without changing its aspect ratio,
-        // by cropping off the edges and enlarging the middle section.
-        CvRect r;
-        // input aspect ratio
-        float origAspect = (origWidth / (float)origHeight);
-        // output aspect ratio
-        float newAspect = (newWidth / (float)newHeight);
-        // crop width to be origHeight * newAspect
-        if (origAspect > newAspect) {
-            int tw = (origHeight * newWidth) / newHeight;
-            r = cvRect((origWidth - tw)/2, 0, tw, origHeight);
-        }
-        else {  // crop height to be origWidth / newAspect
-            int th = (origWidth * newHeight) / newWidth;
-            r = cvRect(0, (origHeight - th)/2, origWidth, th);
-        }
-        IplImage *croppedImg = cropImage(origImg, r);
-
-        // Call this function again, with the new aspect ratio image.
-        // Will do a scaled image resize with the correct aspect ratio.
-        outImg = resizeImage(croppedImg, newHeight, newWidth, 0);
-        cvReleaseImage( &croppedImg );
-    }
-    else {
-
-        // Scale the image to the new dimensions,
-        // even if the aspect ratio will be changed.
-        outImg = cvCreateImage(cvSize(newWidth, newHeight),
-                origImg->depth, origImg->nChannels);
-        if (newWidth > origImg->width && newHeight > origImg->height) {
-            // Make the image larger
-            cvResetImageROI((IplImage*)origImg);
-            // CV_INTER_LINEAR: good at enlarging.
-            // CV_INTER_CUBIC: good at enlarging.           
-            cvResize(origImg, outImg, CV_INTER_LINEAR);
-        }
-        else {
-            // Make the image smaller
-            cvResetImageROI((IplImage*)origImg);
-            // CV_INTER_AREA: good at shrinking (decimation) only.
-            cvResize(origImg, outImg, CV_INTER_AREA);
-        }
-
-    }
-    return outImg;
-}
-
 image ipl_to_image(IplImage* src)
 {
     unsigned char *data = (unsigned char *)src->imageData;
@@ -494,6 +395,44 @@ image ipl_to_image(IplImage* src)
     return out;
 }
 
+// #wikipedia
+image resize_image(image im, int h, int w)
+{
+    image resized = make_image(h, w, im.c);   
+    int r, c, k;
+    float h_scale = (float)(im.h - 1) / (h - 1) - .00001;
+    float w_scale = (float)(im.w - 1) / (w - 1) - .00001;
+    for(k = 0; k < im.c; ++k){
+        for(r = 0; r < h; ++r){
+            for(c = 0; c < w; ++c){
+                float sr = r*h_scale;
+                float sc = c*w_scale;
+                int ir = (int)sr;
+                int ic = (int)sc;
+                float x = sr-ir;
+                float y = sc-ic;
+                float val = (1-x) * (1-y) * get_pixel(im, ir, ic, k) + 
+                    x     * (1-y) * get_pixel(im, ir+1, ic, k) + 
+                    (1-x) *   y   * get_pixel(im, ir, ic+1, k) +
+                    x     *   y   * get_pixel(im, ir+1, ic+1, k);
+                set_pixel(resized, r, c, k, val);
+            }
+        }
+    }
+    return resized;
+}
+
+void test_resize(char *filename)
+{
+    image im = load_image(filename, 0,0);
+    image small = resize_image(im, 63, 65);
+    image big = resize_image(im, 512, 513);
+    show_image(im, "original");
+    show_image(small, "smaller");
+    show_image(big, "bigger");
+    cvWaitKey(0);
+}
+
 image load_image_color(char *filename, int h, int w)
 {
     IplImage* src = 0;
@@ -502,13 +441,12 @@ image load_image_color(char *filename, int h, int w)
         printf("Cannot load file image %s\n", filename);
         exit(0);
     }
-    if(h && w && (src->height != h || src->width != w)){
-        //printf("Resized!\n");
-        IplImage *resized = resizeImage(src, h, w, 0);
-        cvReleaseImage(&src);
-        src = resized;
-    }
     image out = ipl_to_image(src);
+    if((h && w) && (h != out.h || w != out.w)){
+        image resized = resize_image(out, h, w);
+        free_image(out);
+        out = resized;
+    }
     cvReleaseImage(&src);
     return out;
 }
@@ -521,12 +459,12 @@ image load_image(char *filename, int h, int w)
         printf("Cannot load file image %s\n", filename);
         exit(0);
     }
-    if(h && w ){
-        IplImage *resized = resizeImage(src, h, w, 0);
-        cvReleaseImage(&src);
-        src = resized;
-    }
     image out = ipl_to_image(src);
+    if((h && w) && (h != out.h || w != out.w)){
+        image resized = resize_image(out, h, w);
+        free_image(out);
+        out = resized;
+    }
     cvReleaseImage(&src);
     return out;
 }

src/image.h

@@ -66,5 +66,6 @@ void back_convolve(image m, image kernel, int stride, int channel, image out, in
 void kernel_update(image m, image update, int stride, int channel, image out, int edge);
 
 void free_image(image m);
+void test_resize(char *filename);
 #endif