Add decoder part quantization flag for the object detection model.

PiperOrigin-RevId: 448858109

official/projects/qat/vision/configs/common.py

@@ -30,6 +30,8 @@ class Quantization(hyperparams.Config):
     change_num_bits: A `bool` indicates whether to manually allocate num_bits.
     num_bits_weight: An `int` number of bits for weight. Default to 8.
     num_bits_activation: An `int` number of bits for activation. Default to 8.
+    quantize_detection_decoder: A `bool` indicates whether to quantize detection
+      decoder. It only works for detection model.
     quantize_detection_head: A `bool` indicates whether to quantize detection
       head. It only works for detection model.
   """
@@ -37,4 +39,5 @@ class Quantization(hyperparams.Config):
   change_num_bits: bool = False
   num_bits_weight: int = 8
   num_bits_activation: int = 8
+  quantize_detection_decoder: bool = False
   quantize_detection_head: bool = False

official/projects/qat/vision/configs/experiments/retinanet/coco_mobilenetv2_qat_tpu_e2e.yaml

+# --experiment_type=retinanet_spinenet_mobile_coco_qat
+# COCO mAP: 18.4 (Evaluated on the TFLite after conversion.)
+# QAT only supports float32 tpu due to fake-quant op.
+runtime:
+  distribution_strategy: 'tpu'
+  mixed_precision_dtype: 'float32'
+task:
+  losses:
+    l2_weight_decay: 3.0e-05
+  model:
+    anchor:
+      anchor_size: 3
+      aspect_ratios: [0.5, 1.0, 2.0]
+      num_scales: 3
+    backbone:
+      mobilenet:
+        model_id: 'MobileNetV2'
+        filter_size_scale: 1.0
+      type: 'mobilenet'
+    decoder:
+      type: 'fpn'
+      fpn:
+        num_filters: 128
+        use_separable_conv: true
+        use_keras_layer: true
+    head:
+      num_convs: 4
+      num_filters: 128
+      use_separable_conv: true
+    input_size: [256, 256, 3]
+    max_level: 7
+    min_level: 3
+    norm_activation:
+      activation: 'relu6'
+      norm_epsilon: 0.001
+      norm_momentum: 0.99
+      use_sync_bn: true
+  train_data:
+    dtype: 'float32'
+    global_batch_size: 256
+    is_training: true
+    parser:
+      aug_rand_hflip: true
+      aug_scale_max: 2.0
+      aug_scale_min: 0.5
+  validation_data:
+    dtype: 'float32'
+    global_batch_size: 16
+    is_training: false
+  quantization:
+    pretrained_original_checkpoint: 'gs://**/tf2_mobilenetv2_ssd_jul29/28129005/ckpt-277200'
+    quantize_detection_decoder: true
+    quantize_detection_head: true
+trainer:
+  optimizer_config:
+    learning_rate:
+      stepwise:
+        boundaries: [263340, 272580]
+        values: [0.032, 0.0032, 0.00032]
+      type: 'stepwise'
+    warmup:
+      linear:
+        warmup_learning_rate: 0.00067
+        warmup_steps: 2000
+  steps_per_loop: 462
+  train_steps: 277200
+  validation_interval: 462
+  validation_steps: 625

official/projects/qat/vision/modeling/factory.py

@@ -21,13 +21,16 @@ import tensorflow_model_optimization as tfmot
 from official.projects.qat.vision.configs import common
 from official.projects.qat.vision.modeling import segmentation_model as qat_segmentation_model
 from official.projects.qat.vision.modeling.heads import dense_prediction_heads as dense_prediction_heads_qat
+from official.projects.qat.vision.modeling.layers import nn_layers as qat_nn_layers
 from official.projects.qat.vision.n_bit import schemes as n_bit_schemes
+from official.projects.qat.vision.quantization import configs as qat_configs
 from official.projects.qat.vision.quantization import helper
 from official.projects.qat.vision.quantization import schemes
 from official.vision import configs
 from official.vision.modeling import classification_model
 from official.vision.modeling import retinanet_model
 from official.vision.modeling.decoders import aspp
+from official.vision.modeling.decoders import fpn
 from official.vision.modeling.heads import dense_prediction_heads
 from official.vision.modeling.heads import segmentation_heads
 from official.vision.modeling.layers import nn_layers
@@ -120,6 +123,16 @@ def build_qat_classification_model(
   return optimized_model
 
 
+def _clone_function_for_fpn(layer):
+  if isinstance(layer, (
+      tf.keras.layers.BatchNormalization,
+      tf.keras.layers.experimental.SyncBatchNormalization)):
+    return tfmot.quantization.keras.quantize_annotate_layer(
+        qat_nn_layers.BatchNormalizationWrapper(layer),
+        qat_configs.Default8BitOutputQuantizeConfig())
+  return layer
+
+
 def build_qat_retinanet(
     model: tf.keras.Model, quantization: common.Quantization,
     model_config: configs.retinanet.RetinaNet) -> tf.keras.Model:
@@ -144,6 +157,7 @@ def build_qat_retinanet(
 
   scope_dict = {
       'L2': tf.keras.regularizers.l2,
+      'BatchNormalizationWrapper': qat_nn_layers.BatchNormalizationWrapper,
   }
   with tfmot.quantization.keras.quantize_scope(scope_dict):
     annotated_backbone = tfmot.quantization.keras.quantize_annotate_model(
@@ -151,6 +165,17 @@ def build_qat_retinanet(
     optimized_backbone = tfmot.quantization.keras.quantize_apply(
         annotated_backbone,
         scheme=schemes.Default8BitQuantizeScheme())
+    decoder = model.decoder
+    if quantization.quantize_detection_decoder:
+      if not isinstance(decoder, fpn.FPN):
+        raise ValueError('Currently only supports FPN.')
+
+      decoder = tf.keras.models.clone_model(
+          decoder,
+          clone_function=_clone_function_for_fpn,
+      )
+      decoder = tfmot.quantization.keras.quantize_model(decoder)
+
     head = model.head
     if quantization.quantize_detection_head:
       if not isinstance(head, dense_prediction_heads.RetinaNetHead):
@@ -161,7 +186,7 @@ def build_qat_retinanet(
 
   optimized_model = retinanet_model.RetinaNetModel(
       optimized_backbone,
-      model.decoder,
+      decoder,
       head,
       model.detection_generator,
       min_level=model_config.min_level,

official/projects/qat/vision/modeling/factory_test.py

@@ -28,6 +28,7 @@ from official.vision.configs import image_classification as classification_cfg
 from official.vision.configs import retinanet as retinanet_cfg
 from official.vision.configs import semantic_segmentation as semantic_segmentation_cfg
 from official.vision.modeling import factory
+from official.vision.modeling.decoders import fpn
 from official.vision.modeling.heads import dense_prediction_heads
 
 
@@ -69,61 +70,99 @@ class ClassificationModelBuilderTest(parameterized.TestCase, tf.test.TestCase):
 class RetinaNetBuilderTest(parameterized.TestCase, tf.test.TestCase):
 
   @parameterized.parameters(
-      ('spinenet_mobile', (640, 640), False, False),
-      ('spinenet_mobile', (640, 640), False, True),
+      ('spinenet_mobile', 'identity', (640, 640), False, False),
+      ('spinenet_mobile', 'identity', (640, 640), True, False),
+      ('mobilenet', 'fpn', (640, 640), True, False),
+      ('mobilenet', 'fpn', (640, 640), True, True),
   )
   def test_builder(self,
                    backbone_type,
+                   decoder_type,
                    input_size,
-                   has_attribute_heads,
-                   quantize_detection_head):
+                   quantize_detection_head,
+                   quantize_detection_decoder):
     num_classes = 2
     input_specs = tf.keras.layers.InputSpec(
         shape=[None, input_size[0], input_size[1], 3])
-    if has_attribute_heads:
-      attribute_heads_config = [
-          retinanet_cfg.AttributeHead(name='att1'),
-          retinanet_cfg.AttributeHead(
-              name='att2', type='classification', size=2),
-      ]
-    else:
-      attribute_heads_config = None
-    model_config = retinanet_cfg.RetinaNet(
-        num_classes=num_classes,
-        input_size=[input_size[0], input_size[1], 3],
-        backbone=backbones.Backbone(
+
+    if backbone_type == 'spinenet_mobile':
+      backbone_config = backbones.Backbone(
           type=backbone_type,
           spinenet_mobile=backbones.SpineNetMobile(
               model_id='49',
               stochastic_depth_drop_rate=0.2,
               min_level=3,
               max_level=7,
-                use_keras_upsampling_2d=True)),
+              use_keras_upsampling_2d=True))
+    elif backbone_type == 'mobilenet':
+      backbone_config = backbones.Backbone(
+          type=backbone_type,
+          mobilenet=backbones.MobileNet(
+              model_id='MobileNetV2',
+              filter_size_scale=1.0))
+    else:
+      raise ValueError(
+          'backbone_type {} is not supported'.format(backbone_type))
+
+    if decoder_type == 'identity':
+      decoder_config = decoders.Decoder(type=decoder_type)
+    elif decoder_type == 'fpn':
+      decoder_config = decoders.Decoder(
+          type=decoder_type,
+          fpn=decoders.FPN(
+              num_filters=128,
+              use_separable_conv=True,
+              use_keras_layer=True))
+    else:
+      raise ValueError(
+          'decoder_type {} is not supported'.format(decoder_type))
+
+    model_config = retinanet_cfg.RetinaNet(
+        num_classes=num_classes,
+        input_size=[input_size[0], input_size[1], 3],
+        backbone=backbone_config,
+        decoder=decoder_config,
         head=retinanet_cfg.RetinaNetHead(
-            attribute_heads=attribute_heads_config,
+            attribute_heads=None,
             use_separable_conv=True))
+
     l2_regularizer = tf.keras.regularizers.l2(5e-5)
-    quantization_config = common.Quantization(
-        quantize_detection_head=quantize_detection_head)
+    # Build the original float32 retinanet model.
     model = factory.build_retinanet(
         input_specs=input_specs,
         model_config=model_config,
         l2_regularizer=l2_regularizer)
 
+    # Call the model with dummy input to build the head part.
+    dummpy_input = tf.zeros([1] + model_config.input_size)
+    model(dummpy_input, training=True)
+
+    # Build the QAT model from the original model with quantization config.
     qat_model = qat_factory.build_qat_retinanet(
         model=model,
-        quantization=quantization_config,
+        quantization=common.Quantization(
+            quantize_detection_decoder=quantize_detection_decoder,
+            quantize_detection_head=quantize_detection_head),
         model_config=model_config)
-    if has_attribute_heads:
-      self.assertEqual(model_config.head.attribute_heads[0].as_dict(),
-                       dict(name='att1', type='regression', size=1))
-      self.assertEqual(model_config.head.attribute_heads[1].as_dict(),
-                       dict(name='att2', type='classification', size=2))
+
+    if quantize_detection_head:
+      # head become a RetinaNetHeadQuantized when we apply quantization.
+      self.assertIsInstance(qat_model.head,
+                            qat_dense_prediction_heads.RetinaNetHeadQuantized)
+    else:
+      # head is a RetinaNetHead if we don't apply quantization on head part.
       self.assertIsInstance(
-        qat_model.head,
-        (qat_dense_prediction_heads.RetinaNetHeadQuantized
-         if quantize_detection_head else
-         dense_prediction_heads.RetinaNetHead))
+          qat_model.head, dense_prediction_heads.RetinaNetHead)
+      self.assertNotIsInstance(
+          qat_model.head, qat_dense_prediction_heads.RetinaNetHeadQuantized)
+
+    if decoder_type == 'FPN':
+      if quantize_detection_decoder:
+        # FPN decoder become a general keras functional model after applying
+        # quantization.
+        self.assertNotIsInstance(qat_model.decoder, fpn.FPN)
+      else:
+        self.assertIsInstance(qat_model.decoder, fpn.FPN)
 
 
 class SegmentationModelBuilderTest(parameterized.TestCase, tf.test.TestCase):

official/projects/qat/vision/modeling/layers/nn_layers.py

@@ -15,7 +15,7 @@
 """Contains common building blocks for neural networks."""
 
 import enum
-from typing import Callable, Dict, List, Mapping, Optional, Sequence, Tuple, Union
+from typing import Callable, Dict, List, Mapping, Optional, Sequence, Tuple, Union, Any
 
 import tensorflow as tf
 
@@ -767,3 +767,23 @@ class ASPPQuantized(aspp.ASPP):
     level = str(self._config_dict['level'])
     backbone_output = inputs[level] if isinstance(inputs, dict) else inputs
     return self.aspp(backbone_output)
+
+
+class BatchNormalizationWrapper(tf.keras.layers.Wrapper):
+  """A BatchNormalizationWrapper that explicitly not folded.
+
+  It just added an identity depthwise conv right before the normalization.
+  As a result, given normalization op just folded into the identity depthwise
+  conv layer.
+
+  Note that it only used when the batch normalization folding is not working.
+  It makes quantize them as a 1x1 depthwise conv layer that just work as same
+  as inference mode for the normalization. (Basically mult and add for the BN.)
+  """
+
+  def call(self, inputs: tf.Tensor, *args: Any, **kwargs: Any) -> tf.Tensor:
+    channels = tf.shape(inputs)[-1]
+    x = tf.nn.depthwise_conv2d(
+        inputs, tf.ones([1, 1, channels, 1]), [1, 1, 1, 1], 'VALID')
+    outputs = self.layer.call(x, *args, **kwargs)
+    return outputs

official/projects/qat/vision/modeling/layers/nn_layers_test.py

@@ -91,6 +91,17 @@ class NNLayersTest(parameterized.TestCase, tf.test.TestCase):
     self.assertAllEqual([2, input_size, input_size, num_filters],
                         feats.shape.as_list())
 
+  @parameterized.parameters(False, True)
+  def test_bnorm_wrapper_creation(self, use_sync_bn):
+    inputs = tf.keras.Input(shape=(64, 64, 128), dtype=tf.float32)
+    if use_sync_bn:
+      norm = tf.keras.layers.experimental.SyncBatchNormalization(axis=-1)
+    else:
+      norm = tf.keras.layers.BatchNormalization(axis=-1)
+    layer = nn_layers.BatchNormalizationWrapper(norm)
+    output = layer(inputs)
+    self.assertAllEqual([None, 64, 64, 128], output.shape)
+
 
 if __name__ == '__main__':
   tf.test.main()

official/projects/qat/vision/quantization/helper.py

@@ -27,7 +27,9 @@ _QUANTIZATION_WEIGHT_NAMES = [
     'depthwise_kernel_min', 'depthwise_kernel_max',
     'reduce_mean_quantizer_vars_min', 'reduce_mean_quantizer_vars_max',
     'quantize_layer_min', 'quantize_layer_max',
+    'quantize_layer_1_min', 'quantize_layer_1_max',
     'quantize_layer_2_min', 'quantize_layer_2_max',
+    'quantize_layer_3_min', 'quantize_layer_3_max',
     'post_activation_min', 'post_activation_max',
 ]