[Model] update PPDet pybind and docs (#1550)

update pybind and docs

examples/vision/detection/paddledetection/rknpu2/python/README.md

@@ -12,11 +12,10 @@ This directory provides `infer.py` for a quick example of Picodet deployment on
 git clone https://github.com/PaddlePaddle/FastDeploy.git
 cd FastDeploy/examples/vision/detection/paddledetection/rknpu2/python
 
-# Download images.
+# Download images and model
 wget https://gitee.com/paddlepaddle/PaddleDetection/raw/release/2.4/demo/000000014439.jpg
-
-# copy model
-cp -r ./picodet_s_416_coco_lcnet /path/to/FastDeploy/examples/vision/detection/rknpu2detection/paddledetection/python
+wget https://bj.bcebos.com/paddlehub/fastdeploy/rknpu2/picodet_s_416_coco_lcnet.zip
+unzip picodet_s_416_coco_lcnet.zip
 
 # Inference.
 python3 infer.py --model_file ./picodet_s_416_coco_lcnet/picodet_s_416_coco_lcnet_rk3568.rknn  \

examples/vision/detection/paddledetection/rknpu2/python/README_CN.md

@@ -15,8 +15,10 @@ cd FastDeploy/examples/vision/detection/paddledetection/rknpu2/python
 # 下载图片
 wget https://gitee.com/paddlepaddle/PaddleDetection/raw/release/2.4/demo/000000014439.jpg
 
-# copy model
-cp -r ./picodet_s_416_coco_lcnet /path/to/FastDeploy/examples/vision/detection/rknpu2detection/paddledetection/python
+# 下载PPYOLOE模型文件和测试图片
+wget https://bj.bcebos.com/paddlehub/fastdeploy/rknpu2/picodet_s_416_coco_lcnet.zip
+unzip picodet_s_416_coco_lcnet.zip
+wget https://gitee.com/paddlepaddle/PaddleDetection/raw/release/2.4/demo/000000014439.jpg
 
 # 推理
 python3 infer.py --model_file ./picodet_s_416_coco_lcnet/picodet_s_416_coco_lcnet_rk3568.rknn  \

examples/vision/detection/paddledetection/rknpu2/python/infer.py

@@ -55,7 +55,7 @@ if __name__ == "__main__":
         model_format=fd.ModelFormat.RKNN)
     model.preprocessor.disable_normalize()
     model.preprocessor.disable_permute()
-    model.postprocessor.apply_decode_and_nms()
+    model.postprocessor.apply_nms()
 
     # 预测图片分割结果
     im = cv2.imread(args.image)