add bbox range limit. test=develop

paddle/fluid/operators/detection/yolo_box_op.cu

@@ -52,7 +52,7 @@ __global__ void KeYoloBoxFw(const T* input, const int* imgsize, T* boxes,
     GetYoloBox<T>(box, input, anchors, l, k, j, h, input_size, box_idx,
                                 grid_num, img_height, img_width);
     box_idx = (i * box_num + j * grid_num + k * w + l) * 4;
-    CalcDetectionBox<T>(boxes, box, box_idx);
+    CalcDetectionBox<T>(boxes, box, box_idx, img_height, img_width);
 
     int label_idx =
         GetEntryIndex(i, j, k * w + l, an_num, an_stride, grid_num, 5);

paddle/fluid/operators/detection/yolo_box_op.h

@@ -46,12 +46,17 @@ HOSTDEVICE inline int GetEntryIndex(int batch, int an_idx, int hw_idx,
 }
 
 template <typename T>
-HOSTDEVICE inline void CalcDetectionBox(T* boxes, T* box,
-                                        const int box_idx) {
+HOSTDEVICE inline void CalcDetectionBox(T* boxes, T* box, const int box_idx,
+                                        const int img_height, const int img_width) {
   boxes[box_idx] = box[0] - box[2] / 2;
   boxes[box_idx + 1] = box[1] - box[3] / 2;
   boxes[box_idx + 2] = box[0] + box[2] / 2;
   boxes[box_idx + 3] = box[1] + box[3] / 2;
+  
+  boxes[box_idx] = boxes[box_idx] > 0 ? boxes[box_idx] : static_cast<T>(0);
+  boxes[box_idx + 1] = boxes[box_idx + 1] > 0 ? boxes[box_idx + 1] : static_cast<T>(0);
+  boxes[box_idx + 2] = boxes[box_idx + 2] < img_width - 1 ? boxes[box_idx + 2] : static_cast<T>(img_width - 1);
+  boxes[box_idx + 3] = boxes[box_idx + 3] < img_height - 1 ? boxes[box_idx + 3] : static_cast<T>(img_height - 1);
 }
 
 template <typename T>
@@ -118,7 +123,7 @@ class YoloBoxKernel : public framework::OpKernel<T> {
 	    GetYoloBox<T>(box, input_data, anchors_, l, k, j, h, input_size,
 		          box_idx, stride, img_height, img_width);
             box_idx = (i * box_num + j * stride + k * w + l) * 4;
-            CalcDetectionBox<T>(boxes_data, box, box_idx);
+            CalcDetectionBox<T>(boxes_data, box, box_idx, img_height, img_width);
 
             int label_idx =
                 GetEntryIndex(i, j, k * w + l, an_num, an_stride, stride, 5);