From 0f110834f4e18b30d5f101bf8f1724c34b7b83db Mon Sep 17 00:00:00 2001
From: Joseph Redmon <pjreddie@gmail.com>
Date: Thu, 15 Mar 2018 15:23:14 -0700
Subject: [PATCH] faster nms and stuff

---
 examples/coco.c     |  6 ++--
 examples/detector.c | 47 ++++++++++++-------------
 examples/yolo.c     |  6 ++--
 include/darknet.h   |  7 ++--
 python/darknet.py   | 12 +++----
 src/box.c           | 11 ++++++
 src/demo.c          | 22 +++++-------
 src/network.c       | 21 ++++++-----
 src/region_layer.c  | 86 +++++++++++++++++++++++++++++----------------
 src/region_layer.h  |  1 +
 10 files changed, 126 insertions(+), 93 deletions(-)

diff --git a/examples/coco.c b/examples/coco.c
index 6d9638c4..a5a526e5 100644
--- a/examples/coco.c
+++ b/examples/coco.c
@@ -146,7 +146,7 @@ void validate_coco(char *cfg, char *weights)
     FILE *fp = fopen(buff, "w");
     fprintf(fp, "[\n");
 
-    detection *dets = make_network_boxes(net);
+    detection *dets = make_network_boxes(net, 0);
 
     int m = plist->size;
     int i=0;
@@ -231,7 +231,7 @@ void validate_coco_recall(char *cfgfile, char *weightfile)
         snprintf(buff, 1024, "%s%s.txt", base, coco_classes[j]);
         fps[j] = fopen(buff, "w");
     }
-    detection *dets = make_network_boxes(net);
+    detection *dets = make_network_boxes(net, 0);
 
     int m = plist->size;
     int i=0;
@@ -302,7 +302,7 @@ void test_coco(char *cfgfile, char *weightfile, char *filename, float thresh)
     clock_t time;
     char buff[256];
     char *input = buff;
-    detection *dets = make_network_boxes(net);
+    detection *dets = make_network_boxes(net, 0);
     while(1){
         if(filename){
             strncpy(input, filename, 256);
diff --git a/examples/detector.c b/examples/detector.c
index 5bf8ac40..c7c2c73b 100644
--- a/examples/detector.c
+++ b/examples/detector.c
@@ -279,8 +279,6 @@ void validate_detector_flip(char *datacfg, char *cfgfile, char *weightfile, char
         }
     }
 
-    detection *dets = make_network_boxes(net);
-
     int m = plist->size;
     int i=0;
     int t;
@@ -333,15 +331,17 @@ void validate_detector_flip(char *datacfg, char *cfgfile, char *weightfile, char
             network_predict(net, input.data);
             int w = val[t].w;
             int h = val[t].h;
-            fill_network_boxes(net, w, h, thresh, .5, map, 0, dets);
-            if (nms) do_nms_sort(dets, l.w*l.h*l.n, classes, nms);
+            int num = 0;
+            detection *dets = get_network_boxes(net, w, h, thresh, .5, map, 0, &num);
+            if (nms) do_nms_sort(dets, num, classes, nms);
             if (coco){
-                print_cocos(fp, path, dets, l.w*l.h*l.n, classes, w, h);
+                print_cocos(fp, path, dets, num, classes, w, h);
             } else if (imagenet){
-                print_imagenet_detections(fp, i+t-nthreads+1, dets, l.w*l.h*l.n, classes, w, h);
+                print_imagenet_detections(fp, i+t-nthreads+1, dets, num, classes, w, h);
             } else {
-                print_detector_detections(fps, id, dets, l.w*l.h*l.n, classes, w, h);
+                print_detector_detections(fps, id, dets, num, classes, w, h);
             }
+            free_detections(dets, num);
             free(id);
             free_image(val[t]);
             free_image(val_resized[t]);
@@ -409,8 +409,6 @@ void validate_detector(char *datacfg, char *cfgfile, char *weightfile, char *out
         }
     }
 
-    detection *dets = make_network_boxes(net);
-    int nboxes = num_boxes(net);
 
     int m = plist->size;
     int i=0;
@@ -459,7 +457,8 @@ void validate_detector(char *datacfg, char *cfgfile, char *weightfile, char *out
             network_predict(net, X);
             int w = val[t].w;
             int h = val[t].h;
-            fill_network_boxes(net, w, h, thresh, .5, map, 0, dets);
+            int nboxes = 0;
+            detection *dets = get_network_boxes(net, w, h, thresh, .5, map, 0, &nboxes);
             if (nms) do_nms_sort(dets, nboxes, classes, nms);
             if (coco){
                 print_cocos(fp, path, dets, nboxes, classes, w, h);
@@ -497,7 +496,6 @@ void validate_detector_recall(char *cfgfile, char *weightfile)
     layer l = net->layers[net->n-1];
 
     int j, k;
-    detection *dets = make_network_boxes(net);
 
     int m = plist->size;
     int i=0;
@@ -510,7 +508,6 @@ void validate_detector_recall(char *cfgfile, char *weightfile)
     int correct = 0;
     int proposals = 0;
     float avg_iou = 0;
-    int nboxes = num_boxes(net);
 
     for(i = 0; i < m; ++i){
         char *path = paths[i];
@@ -518,7 +515,8 @@ void validate_detector_recall(char *cfgfile, char *weightfile)
         image sized = resize_image(orig, net->w, net->h);
         char *id = basecfg(path);
         network_predict(net, sized.data);
-        fill_network_boxes(net, sized.w, sized.h, thresh, .5, 0, 1, dets);
+        int nboxes = 0;
+        detection *dets = get_network_boxes(net, sized.w, sized.h, thresh, .5, 0, 1, &nboxes);
         if (nms) do_nms_obj(dets, nboxes, 1, nms);
 
         char labelpath[4096];
@@ -590,18 +588,18 @@ void test_detector(char *datacfg, char *cfgfile, char *weightfile, char *filenam
         //resize_network(net, sized.w, sized.h);
         layer l = net->layers[net->n-1];
 
-        int nboxes = num_boxes(net);
-        printf("%d\n", nboxes);
 
         float *X = sized.data;
         time=what_time_is_it_now();
         network_predict(net, X);
         printf("%s: Predicted in %f seconds.\n", input, what_time_is_it_now()-time);
-        detection *dets = get_network_boxes(net, im.w, im.h, thresh, hier_thresh, 0, 1);
+        int nboxes = 0;
+        detection *dets = get_network_boxes(net, im.w, im.h, thresh, hier_thresh, 0, 1, &nboxes);
+        printf("%d\n", nboxes);
         //if (nms) do_nms_obj(boxes, probs, l.w*l.h*l.n, l.classes, nms);
         if (nms) do_nms_sort(dets, nboxes, l.classes, nms);
         draw_detections(im, dets, nboxes, thresh, names, alphabet, l.classes);
-        free_detections(dets, num_boxes(net));
+        free_detections(dets, nboxes);
         if(outfile){
             save_image(im, outfile);
         }
@@ -673,11 +671,10 @@ void censor_detector(char *datacfg, char *cfgfile, char *weightfile, int cam_ind
         image in_s = letterbox_image(in, net->w, net->h);
         layer l = net->layers[net->n-1];
 
-        int nboxes = num_boxes(net);
-
         float *X = in_s.data;
         network_predict(net, X);
-        detection *dets = get_network_boxes(net, in.w, in.h, thresh, 0, 0, 0);
+        int nboxes = 0;
+        detection *dets = get_network_boxes(net, in.w, in.h, thresh, 0, 0, 0, &nboxes);
         //if (nms) do_nms_obj(boxes, probs, l.w*l.h*l.n, l.classes, nms);
         if (nms) do_nms_sort(dets, nboxes, l.classes, nms);
 
@@ -691,7 +688,7 @@ void censor_detector(char *datacfg, char *cfgfile, char *weightfile, int cam_ind
         }
         show_image(in, base);
         cvWaitKey(10);
-        free_detections(dets, num_boxes(net));
+        free_detections(dets, nboxes);
 
 
         free_image(in_s);
@@ -756,12 +753,12 @@ void extract_detector(char *datacfg, char *cfgfile, char *weightfile, int cam_in
         image in_s = letterbox_image(in, net->w, net->h);
         layer l = net->layers[net->n-1];
 
-        int nboxes = num_boxes(net);
         show_image(in, base);
 
+        int nboxes = 0;
         float *X = in_s.data;
         network_predict(net, X);
-        detection *dets = get_network_boxes(net, in.w, in.h, thresh, 0, 0, 1);
+        detection *dets = get_network_boxes(net, in.w, in.h, thresh, 0, 0, 1, &nboxes);
         //if (nms) do_nms_obj(boxes, probs, l.w*l.h*l.n, l.classes, nms);
         if (nms) do_nms_sort(dets, nboxes, l.classes, nms);
 
@@ -779,7 +776,7 @@ void extract_detector(char *datacfg, char *cfgfile, char *weightfile, int cam_in
                 free_image(bim);
             }
         }
-        free_detections(dets, num_boxes(net));
+        free_detections(dets, nboxes);
 
 
         free_image(in_s);
@@ -795,6 +792,7 @@ void extract_detector(char *datacfg, char *cfgfile, char *weightfile, int cam_in
     }
 }
 
+/*
 void network_detect(network *net, image im, float thresh, float hier_thresh, float nms, detection *dets)
 {
     network_predict_image(net, im);
@@ -803,6 +801,7 @@ void network_detect(network *net, image im, float thresh, float hier_thresh, flo
     fill_network_boxes(net, im.w, im.h, thresh, hier_thresh, 0, 0, dets);
     if (nms) do_nms_sort(dets, nboxes, l.classes, nms);
 }
+*/
 
 void run_detector(int argc, char **argv)
 {
diff --git a/examples/yolo.c b/examples/yolo.c
index af4b8b50..ef8777c8 100644
--- a/examples/yolo.c
+++ b/examples/yolo.c
@@ -133,7 +133,7 @@ void validate_yolo(char *cfg, char *weights)
     image *buf = calloc(nthreads, sizeof(image));
     image *buf_resized = calloc(nthreads, sizeof(image));
     pthread_t *thr = calloc(nthreads, sizeof(pthread_t));
-    detection *dets = make_network_boxes(net);
+    detection *dets = make_network_boxes(net, 0);
 
     load_args args = {0};
     args.w = net->w;
@@ -200,7 +200,7 @@ void validate_yolo_recall(char *cfg, char *weights)
         snprintf(buff, 1024, "%s%s.txt", base, voc_names[j]);
         fps[j] = fopen(buff, "w");
     }
-    detection *dets = make_network_boxes(net);
+    detection *dets = make_network_boxes(net, 0);
 
     int m = plist->size;
     int i=0;
@@ -271,7 +271,7 @@ void test_yolo(char *cfgfile, char *weightfile, char *filename, float thresh)
     char buff[256];
     char *input = buff;
     float nms=.4;
-    detection *dets = make_network_boxes(net);
+    detection *dets = make_network_boxes(net, 0);
     while(1){
         if(filename){
             strncpy(input, filename, 256);
diff --git a/include/darknet.h b/include/darknet.h
index 81a01957..000cef98 100644
--- a/include/darknet.h
+++ b/include/darknet.h
@@ -682,7 +682,7 @@ void save_weights_upto(network *net, char *filename, int cutoff);
 void load_weights_upto(network *net, char *filename, int start, int cutoff);
 
 void zero_objectness(layer l);
-void get_region_detections(layer l, int w, int h, int netw, int neth, float thresh, int *map, float tree_thresh, int relative, detection *dets);
+int get_region_detections(layer l, int w, int h, int netw, int neth, float thresh, int *map, float tree_thresh, int relative, detection *dets);
 void free_network(network *net);
 void set_batch_network(network *net, int b);
 void set_temp_network(network *net, float t);
@@ -739,10 +739,7 @@ int network_width(network *net);
 int network_height(network *net);
 float *network_predict_image(network *net, image im);
 void network_detect(network *net, image im, float thresh, float hier_thresh, float nms, detection *dets);
-int num_boxes(network *net);
-detection *get_network_boxes(network *net, int w, int h, float thresh, float hier, int *map, int relative);
-void fill_network_boxes(network *net, int w, int h, float thresh, float hier, int *map, int relative, detection *dets);
-detection *make_network_boxes(network *net);
+detection *get_network_boxes(network *net, int w, int h, float thresh, float hier, int *map, int relative, int *num);
 void free_detections(detection *dets, int n);
 
 void reset_network_state(network *net, int b);
diff --git a/python/darknet.py b/python/darknet.py
index 675d2024..88d84cdb 100644
--- a/python/darknet.py
+++ b/python/darknet.py
@@ -63,7 +63,7 @@ make_image.argtypes = [c_int, c_int, c_int]
 make_image.restype = IMAGE
 
 get_network_boxes = lib.get_network_boxes
-get_network_boxes.argtypes = [c_void_p, c_int, c_int, c_float, c_float, POINTER(c_int), c_int]
+get_network_boxes.argtypes = [c_void_p, c_int, c_int, c_float, c_float, POINTER(c_int), c_int, POINTER(c_int)]
 get_network_boxes.restype = POINTER(DETECTION)
 
 make_network_boxes = lib.make_network_boxes
@@ -76,10 +76,6 @@ free_detections.argtypes = [POINTER(DETECTION), c_int]
 free_ptrs = lib.free_ptrs
 free_ptrs.argtypes = [POINTER(c_void_p), c_int]
 
-num_boxes = lib.num_boxes
-num_boxes.argtypes = [c_void_p]
-num_boxes.restype = c_int
-
 network_predict = lib.network_predict
 network_predict.argtypes = [c_void_p, POINTER(c_float)]
 
@@ -128,9 +124,11 @@ def classify(net, meta, im):
 
 def detect(net, meta, image, thresh=.5, hier_thresh=.5, nms=.45):
     im = load_image(image, 0, 0)
-    num =   num_boxes(net)
+    num = c_int(0)
+    pnum = pointer(num)
     predict_image(net, im)
-    dets = get_network_boxes(net, im.w, im.h, thresh, hier_thresh, None, 0)
+    dets = get_network_boxes(net, im.w, im.h, thresh, hier_thresh, None, 0, pnum)
+    num = pnum[0]
     if (nms): do_nms_obj(dets, num, meta.classes, nms);
 
     res = []
diff --git a/src/box.c b/src/box.c
index f0a3504d..8a1772c9 100644
--- a/src/box.c
+++ b/src/box.c
@@ -21,6 +21,17 @@ int nms_comparator(const void *pa, const void *pb)
 void do_nms_obj(detection *dets, int total, int classes, float thresh)
 {
     int i, j, k;
+    k = total-1;
+    for(i = 0; i <= k; ++i){
+        if(dets[i].objectness == 0){
+            detection swap = dets[i];
+            dets[i] = dets[k];
+            dets[k] = swap;
+            --k;
+            --i;
+        }
+    }
+    total = k+1;
 
     for(i = 0; i < total; ++i){
         dets[i].sort_class = -1;
diff --git a/src/demo.c b/src/demo.c
index 68294b43..8ed523df 100644
--- a/src/demo.c
+++ b/src/demo.c
@@ -30,17 +30,12 @@ static int running = 0;
 
 static int demo_frame = 3;
 static int demo_index = 0;
-static int demo_detections = 0;
 //static float **predictions;
-static detection **dets;
-static detection *avg;
 //static float *avg;
 static int demo_done = 0;
 double demo_time;
 
-detection *get_network_boxes(network *net, int w, int h, float thresh, float hier, int *map, int relative);
-detection *make_network_boxes(network *net);
-void fill_network_boxes(network *net, int w, int h, float thresh, float hier, int *map, int relative, detection *dets);
+detection *get_network_boxes(network *net, int w, int h, float thresh, float hier, int *map, int relative, int *num);
 
 void *detect_in_thread(void *ptr)
 {
@@ -55,12 +50,15 @@ void *detect_in_thread(void *ptr)
     if(l.type == DETECTION){
         get_detection_boxes(l, 1, 1, demo_thresh, probs, boxes, 0);
     } else */
+    detection *dets;
+    int nboxes = 0;
     if (l.type == REGION){
-        fill_network_boxes(net, buff[0].w, buff[0].h, demo_thresh, demo_hier, 0, 1, dets[demo_index]);
+        dets = get_network_boxes(net, buff[0].w, buff[0].h, demo_thresh, demo_hier, 0, 1, &nboxes);
     } else {
         error("Last layer must produce detections\n");
     }
 
+/*
     int i,j;
     box zero = {0};
     int classes = l.classes;
@@ -79,15 +77,17 @@ void *detect_in_thread(void *ptr)
         //copy_cpu(classes, dets[0][i].prob, 1, avg[i].prob, 1);
         //avg[i].objectness = dets[0][i].objectness;
     }
+    */
 
-    if (nms > 0) do_nms_obj(avg, demo_detections, l.classes, nms);
+    if (nms > 0) do_nms_obj(dets, nboxes, l.classes, nms);
 
     printf("\033[2J");
     printf("\033[1;1H");
     printf("\nFPS:%.1f\n",fps);
     printf("Objects:\n\n");
     image display = buff[(buff_index+2) % 3];
-    draw_detections(display, avg, demo_detections, demo_thresh, demo_names, demo_alphabet, demo_classes);
+    draw_detections(display, dets, nboxes, demo_thresh, demo_names, demo_alphabet, demo_classes);
+    free_detections(dets, nboxes);
 
     demo_index = (demo_index + 1)%demo_frame;
     running = 0;
@@ -174,11 +174,7 @@ void demo(char *cfgfile, char *weightfile, float thresh, int cam_index, const ch
 
     if(!cap) error("Couldn't connect to webcam.\n");
 
-    demo_detections = num_boxes(net);
-    avg = make_network_boxes(net);
-    dets = calloc(demo_frame, sizeof(detection*));
     int i;
-    for(i = 0; i < demo_frame; ++i) dets[i] = make_network_boxes(net);
 
     buff[0] = get_image_from_stream(cap);
     buff[1] = copy_image(buff[0]);
diff --git a/src/network.c b/src/network.c
index f4966211..656071fc 100644
--- a/src/network.c
+++ b/src/network.c
@@ -502,24 +502,28 @@ float *network_predict(network *net, float *input)
     return out;
 }
 
-int num_boxes(network *net)
+int num_detections(network *net, float thresh)
 {
     int i;
     int s = 0;
     for(i = 0; i < net->n; ++i){
         layer l = net->layers[i];
-        if(l.type == REGION || l.type == DETECTION){
+        if(l.type == REGION){
+            s += region_num_detections(l, thresh);
+        }
+        if(l.type == DETECTION){
             s += l.w*l.h*l.n;
         }
     }
     return s;
 }
 
-detection *make_network_boxes(network *net)
+detection *make_network_boxes(network *net, float thresh, int *num)
 {
     layer l = net->layers[net->n - 1];
     int i;
-    int nboxes = num_boxes(net);
+    int nboxes = num_detections(net, thresh);
+    if(num) *num = nboxes;
     detection *dets = calloc(nboxes, sizeof(detection));
     for(i = 0; i < nboxes; ++i){
         dets[i].prob = calloc(l.classes, sizeof(float));
@@ -529,14 +533,15 @@ detection *make_network_boxes(network *net)
     }
     return dets;
 }
+
 void fill_network_boxes(network *net, int w, int h, float thresh, float hier, int *map, int relative, detection *dets)
 {
     int j;
     for(j = 0; j < net->n; ++j){
         layer l = net->layers[j];
         if(l.type == REGION){
-            get_region_detections(l, w, h, net->w, net->h, thresh, map, hier, relative, dets);
-            dets += l.w*l.h*l.n;
+            int count = get_region_detections(l, w, h, net->w, net->h, thresh, map, hier, relative, dets);
+            dets += count;
         }
         if(l.type == DETECTION){
             get_detection_detections(l, w, h, thresh, dets);
@@ -545,9 +550,9 @@ void fill_network_boxes(network *net, int w, int h, float thresh, float hier, in
     }
 }
 
-detection *get_network_boxes(network *net, int w, int h, float thresh, float hier, int *map, int relative)
+detection *get_network_boxes(network *net, int w, int h, float thresh, float hier, int *map, int relative, int *num)
 {
-    detection *dets = make_network_boxes(net);
+    detection *dets = make_network_boxes(net, thresh, num);
     fill_network_boxes(net, w, h, thresh, hier, map, relative, dets);
     return dets;
 }
diff --git a/src/region_layer.c b/src/region_layer.c
index 5ad7bc0a..fc2a5b26 100644
--- a/src/region_layer.c
+++ b/src/region_layer.c
@@ -412,44 +412,69 @@ void correct_region_boxes(detection *dets, int n, int w, int h, int netw, int ne
     }
 }
 
-void get_region_detections(layer l, int w, int h, int netw, int neth, float thresh, int *map, float tree_thresh, int relative, detection *dets)
+int region_num_detections(layer l, float thresh)
 {
-    int i,j,n,z;
-    float *predictions = l.output;
-    if (l.batch == 2) {
-        float *flip = l.output + l.outputs;
-        for (j = 0; j < l.h; ++j) {
-            for (i = 0; i < l.w/2; ++i) {
-                for (n = 0; n < l.n; ++n) {
-                    for(z = 0; z < l.classes + l.coords + 1; ++z){
-                        int i1 = z*l.w*l.h*l.n + n*l.w*l.h + j*l.w + i;
-                        int i2 = z*l.w*l.h*l.n + n*l.w*l.h + j*l.w + (l.w - i - 1);
-                        float swap = flip[i1];
-                        flip[i1] = flip[i2];
-                        flip[i2] = swap;
-                        if(z == 0){
-                            flip[i1] = -flip[i1];
-                            flip[i2] = -flip[i2];
-                        }
-                    }
-                }
-            }
-        }
-        for(i = 0; i < l.outputs; ++i){
-            l.output[i] = (l.output[i] + flip[i])/2.;
-        }
-    }
+    int i, n;
+    int count = 0;
     for (i = 0; i < l.w*l.h; ++i){
         int row = i / l.w;
         int col = i % l.w;
         for(n = 0; n < l.n; ++n){
             int index = n*l.w*l.h + i;
+            int obj_index  = entry_index(l, 0, n*l.w*l.h + i, l.coords);
+            if(l.output[obj_index] > thresh){
+                ++count;
+            }
+        }
+    }
+    return count;
+}
+
+void avg_flipped_region(layer l)
+{
+    int i,j,n,z;
+    float *flip = l.output + l.outputs;
+    for (j = 0; j < l.h; ++j) {
+        for (i = 0; i < l.w/2; ++i) {
+            for (n = 0; n < l.n; ++n) {
+                for(z = 0; z < l.classes + l.coords + 1; ++z){
+                    int i1 = z*l.w*l.h*l.n + n*l.w*l.h + j*l.w + i;
+                    int i2 = z*l.w*l.h*l.n + n*l.w*l.h + j*l.w + (l.w - i - 1);
+                    float swap = flip[i1];
+                    flip[i1] = flip[i2];
+                    flip[i2] = swap;
+                    if(z == 0){
+                        flip[i1] = -flip[i1];
+                        flip[i2] = -flip[i2];
+                    }
+                }
+            }
+        }
+    }
+    for(i = 0; i < l.outputs; ++i){
+        l.output[i] = (l.output[i] + flip[i])/2.;
+    }
+}
+
+int get_region_detections(layer l, int w, int h, int netw, int neth, float thresh, int *map, float tree_thresh, int relative, detection *dets)
+{
+    int i,j,n,z;
+    float *predictions = l.output;
+    if (l.batch == 2) avg_flipped_region(l);
+    int count = 0;
+    for (i = 0; i < l.w*l.h; ++i){
+        int row = i / l.w;
+        int col = i % l.w;
+        for(n = 0; n < l.n; ++n){
+            int obj_index  = entry_index(l, 0, n*l.w*l.h + i, l.coords);
+            if(predictions[obj_index] <= thresh) continue;
+            int index = count;
+            ++count;
+            int box_index  = entry_index(l, 0, n*l.w*l.h + i, 0);
+            int mask_index = entry_index(l, 0, n*l.w*l.h + i, 4);
             for (j = 0; j < l.classes; ++j) {
                 dets[index].prob[j] = 0;
             }
-            int obj_index  = entry_index(l, 0, n*l.w*l.h + i, l.coords);
-            int box_index  = entry_index(l, 0, n*l.w*l.h + i, 0);
-            int mask_index = entry_index(l, 0, n*l.w*l.h + i, 4);
             float scale = l.background ? 1 : predictions[obj_index];
             dets[index].bbox = get_region_box(predictions, l.biases, l.mask[n], box_index, col, row, l.w, l.h, netw, neth, l.w*l.h);
             dets[index].objectness = scale > thresh ? scale : 0;
@@ -485,7 +510,8 @@ void get_region_detections(layer l, int w, int h, int netw, int neth, float thre
             }
         }
     }
-    correct_region_boxes(dets, l.w*l.h*l.n, w, h, netw, neth, relative);
+    correct_region_boxes(dets, count, w, h, netw, neth, relative);
+    return count;
 }
 
 #ifdef GPU
diff --git a/src/region_layer.h b/src/region_layer.h
index 5aafe249..a455ebf7 100644
--- a/src/region_layer.h
+++ b/src/region_layer.h
@@ -9,6 +9,7 @@ layer make_region_layer(int batch, int h, int w, int n, int total, int *mask, in
 void forward_region_layer(const layer l, network net);
 void backward_region_layer(const layer l, network net);
 void resize_region_layer(layer *l, int w, int h);
+int region_num_detections(layer l, float thresh);
 
 #ifdef GPU
 void forward_region_layer_gpu(const layer l, network net);