TensorFlow.js export enhancements (#4905)

* Add arguments to TensorFlow NMS call

* Add regex substitution to reorder Identity_*

* Delete reorder in docstring

* Cleanup

* Cleanup2

* Removed `+ \` on string ends (not needed)

Co-authored-by: Glenn Jocher <glenn.jocher@ultralytics.com>

export.py

@@ -14,7 +14,6 @@ Inference:
                                          yolov5s.tflite
 
 TensorFlow.js:
-    $ # Edit yolov5s_web_model/model.json to sort Identity* in ascending order
     $ cd .. && git clone https://github.com/zldrobit/tfjs-yolov5-example.git && cd tfjs-yolov5-example
     $ npm install
     $ ln -s ../../yolov5/yolov5s_web_model public/yolov5s_web_model
@@ -213,16 +212,32 @@ def export_tfjs(keras_model, im, file, prefix=colorstr('TensorFlow.js:')):
     # YOLOv5 TensorFlow.js export
     try:
         check_requirements(('tensorflowjs',))
+        import re
         import tensorflowjs as tfjs
 
         print(f'\n{prefix} starting export with tensorflowjs {tfjs.__version__}...')
         f = str(file).replace('.pt', '_web_model')  # js dir
         f_pb = file.with_suffix('.pb')  # *.pb path
+        f_json = f + '/model.json'  # *.json path
 
         cmd = f"tensorflowjs_converter --input_format=tf_frozen_model " \
               f"--output_node_names='Identity,Identity_1,Identity_2,Identity_3' {f_pb} {f}"
         subprocess.run(cmd, shell=True)
 
+        json = open(f_json).read()
+        with open(f_json, 'w') as j:  # sort JSON Identity_* in ascending order
+            subst = re.sub(
+                r'{"outputs": {"Identity.?.?": {"name": "Identity.?.?"}, '
+                r'"Identity.?.?": {"name": "Identity.?.?"}, '
+                r'"Identity.?.?": {"name": "Identity.?.?"}, '
+                r'"Identity.?.?": {"name": "Identity.?.?"}}}',
+                r'{"outputs": {"Identity": {"name": "Identity"}, '
+                r'"Identity_1": {"name": "Identity_1"}, '
+                r'"Identity_2": {"name": "Identity_2"}, '
+                r'"Identity_3": {"name": "Identity_3"}}}',
+                json)
+            j.write(subst)
+
         print(f'{prefix} export success, saved as {f} ({file_size(f):.1f} MB)')
     except Exception as e:
         print(f'\n{prefix} export failure: {e}')
@@ -243,6 +258,10 @@ def run(data=ROOT / 'data/coco128.yaml',  # 'dataset.yaml path'
         dynamic=False,  # ONNX/TF: dynamic axes
         simplify=False,  # ONNX: simplify model
         opset=12,  # ONNX: opset version
+        topk_per_class=100,  # TF.js NMS: topk per class to keep
+        topk_all=100,  # TF.js NMS: topk for all classes to keep
+        iou_thres=0.45,  # TF.js NMS: IoU threshold
+        conf_thres=0.25  # TF.js NMS: confidence threshold
         ):
     t = time.time()
     include = [x.lower() for x in include]
@@ -290,7 +309,9 @@ def run(data=ROOT / 'data/coco128.yaml',  # 'dataset.yaml path'
     if any(tf_exports):
         pb, tflite, tfjs = tf_exports[1:]
         assert not (tflite and tfjs), 'TFLite and TF.js models must be exported separately, please pass only one type.'
-        model = export_saved_model(model, im, file, dynamic, tf_nms=tfjs, agnostic_nms=tfjs)  # keras model
+        model = export_saved_model(model, im, file, dynamic, tf_nms=tfjs, agnostic_nms=tfjs,
+                                   topk_per_class=topk_per_class, topk_all=topk_all, conf_thres=conf_thres,
+                                   iou_thres=iou_thres)  # keras model
         if pb or tfjs:  # pb prerequisite to tfjs
             export_pb(model, im, file)
         if tflite:
@@ -319,6 +340,10 @@ def parse_opt():
     parser.add_argument('--dynamic', action='store_true', help='ONNX/TF: dynamic axes')
     parser.add_argument('--simplify', action='store_true', help='ONNX: simplify model')
     parser.add_argument('--opset', type=int, default=13, help='ONNX: opset version')
+    parser.add_argument('--topk-per-class', type=int, default=100, help='TF.js NMS: topk per class to keep')
+    parser.add_argument('--topk-all', type=int, default=100, help='TF.js NMS: topk for all classes to keep')
+    parser.add_argument('--iou-thres', type=float, default=0.45, help='TF.js NMS: IoU threshold')
+    parser.add_argument('--conf-thres', type=float, default=0.25, help='TF.js NMS: confidence threshold')
     parser.add_argument('--include', nargs='+',
                         default=['torchscript', 'onnx'],
                         help='available formats are (torchscript, onnx, coreml, saved_model, pb, tflite, tfjs)')

models/tf.py

@@ -367,7 +367,7 @@ class AgnosticNMS(keras.layers.Layer):
     # TF Agnostic NMS
     def call(self, input, topk_all, iou_thres, conf_thres):
         # wrap map_fn to avoid TypeSpec related error https://stackoverflow.com/a/65809989/3036450
-        return tf.map_fn(self._nms, input,
+        return tf.map_fn(lambda x: self._nms(x, topk_all, iou_thres, conf_thres), input,
                          fn_output_signature=(tf.float32, tf.float32, tf.float32, tf.int32),
                          name='agnostic_nms')