mask rcnn 部署小技巧

int8进行网络传输

目的:

我们项目需要用到instance segmentation, 所以 rcnn_mask输出层数据量特别大,同时因为图片尺寸有1024*1024*3这么大.
如果不压缩一下直接进行网络传输,数据量会很大,接口延迟很高.
为了部署后,请求推理服务时,数据输入层和输出层的传输量减少.
从float32 转变成 int8,传输量减少了4倍.

处理:

输入层:

先转换成 int8,然后再转成float32

 def build(self, mode, config):
         input_image = KL.Input(
            shape=[None, None, config.IMAGE_SHAPE[2]], name="input_image",dtype=tf.int8)
        input_image = KL.Input(tensor=K.cast(input_image,dtype= tf.float32))

输出层:

   mrcnn_mask = build_fpn_mask_graph(detection_boxes, mrcnn_feature_maps,
                                             input_image_meta,
                                             config.MASK_POOL_SIZE,
                                             config.NUM_CLASSES,
                                             train_bn=config.TRAIN_BN)
              #模型导出时加上去
           mrcnn_mask = KL.Lambda(lambda x: x*255)(mrcnn_mask)
           mrcnn_mask = KL.Lambda(lambda x: tf.cast(x,dtype=tf.int8))(mrcnn_mask)

云函数服务拿到mrcnn_mask输出层数据后,再转换成 float32

模型导出:

导出时注意 output 名称要对应.

def save_model():
   config = QuesConfig()
   PRETRAINED_MODEL_PATH = "/xxxxx/weights"
   MODEL_NAME = 'xxxxx_0601.h5'
   export_dir = "./saved_model/1/"
   h5_to_saved_model(config, PRETRAINED_MODEL_PATH, MODEL_NAME, export_dir)
   
def h5_to_saved_model(config, model_dir, model_name, export_dir):
   if tf.gfile.Exists(export_dir):
       tf.gfile.DeleteRecursively(export_dir)
   config.display()

   model = modellib.MaskRCNN(mode="inference", config=config, model_dir=model_dir)
   model_path = os.path.join(model_dir, model_name)
   model.load_weights(model_path, by_name=True)
   with K.get_session() as session:
       save_m(export_dir, session)
   
def save_m(export_dir, session):
   if tf.gfile.Exists(export_dir):
       tf.gfile.DeleteRecursively(export_dir)
   # legacy_init_op = tf.group(tf.tables_initializer())
   builder = tf.saved_model.builder.SavedModelBuilder(export_dir)
   signature_inputs = {
       "input_image":
           session.graph.get_tensor_by_name("input_image:0"),
       "input_image_meta":
           session.graph.get_tensor_by_name("input_image_meta:0"),
       "input_anchors":
           session.graph.get_tensor_by_name("input_anchors:0"),
   }
   signature_outputs = {
       'mrcnn_detection':
           session.graph.get_tensor_by_name('mrcnn_detection/Reshape_1:0'),
       'mrcnn_mask':
           session.graph.get_tensor_by_name('lambda_5/Cast:0')
   }

   sigs = {}
   sigs['serving_default'] = tf.saved_model.signature_def_utils.predict_signature_def(
       inputs=signature_inputs,
       outputs=signature_outputs)
   builder.add_meta_graph_and_variables(
       session,
       [tf.saved_model.tag_constants.SERVING],
       signature_def_map=sigs

   )
   builder.save()

模型调用

构建网络请求:

   def mold_image(self, images):
      """Expects an RGB image (or array of images) and subtracts
      the mean pixel and converts it to float. Expects image
      colors in RGB order.
      """
      mold_image_fp32 = images.astype(np.float32) - self.config.MEAN_PIXEL
      mold_image_int8 = mold_image_fp32.astype(np.int8)
      return mold_image_int8

解析响应数据:

 # mrcnn_mask = tf.make_ndarray(response.outputs['mrcnn_mask'])
   tensor = response.outputs['mrcnn_mask']
   shape = [d.size for d in tensor.tensor_shape.dim]
   values = np.fromiter(tensor.int_val, dtype=np.int8)
   mrcnn_mask = values.reshape(shape)
   mrcnn_mask = mrcnn_mask.astype(np.float32)

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