Add SegFormer ONNX support (#18006)

* Add ONNX support

* Make height and width dynamic axes
Co-authored-by: Niels Rogge <nielsrogge@Nielss-MacBook-Pro.local>

docs/source/en/serialization.mdx

@@ -90,6 +90,7 @@ Ready-made configurations include the following architectures:
 - ResNet
 - RoBERTa
 - RoFormer
+- SegFormer
 - SqueezeBERT
 - T5
 - ViT

src/transformers/models/segformer/__init__.py

@@ -26,7 +26,9 @@ from ...utils import (
 )
 
 
-_import_structure = {"configuration_segformer": ["SEGFORMER_PRETRAINED_CONFIG_ARCHIVE_MAP", "SegformerConfig"]}
+_import_structure = {
+    "configuration_segformer": ["SEGFORMER_PRETRAINED_CONFIG_ARCHIVE_MAP", "SegformerConfig", "SegformerOnnxConfig"]
+}
 
 try:
     if not is_vision_available():
@@ -69,7 +71,7 @@ else:
 
 
 if TYPE_CHECKING:
-    from .configuration_segformer import SEGFORMER_PRETRAINED_CONFIG_ARCHIVE_MAP, SegformerConfig
+    from .configuration_segformer import SEGFORMER_PRETRAINED_CONFIG_ARCHIVE_MAP, SegformerConfig, SegformerOnnxConfig
 
     try:
         if not is_vision_available():

src/transformers/models/segformer/configuration_segformer.py

@@ -15,8 +15,13 @@
 """ SegFormer model configuration"""
 
 import warnings
+from collections import OrderedDict
+from typing import Mapping
+
+from packaging import version
 
 from ...configuration_utils import PretrainedConfig
+from ...onnx import OnnxConfig
 from ...utils import logging
 
 
@@ -148,3 +153,24 @@ class SegformerConfig(PretrainedConfig):
         self.decoder_hidden_size = decoder_hidden_size
         self.reshape_last_stage = kwargs.get("reshape_last_stage", True)
         self.semantic_loss_ignore_index = semantic_loss_ignore_index
+
+
+class SegformerOnnxConfig(OnnxConfig):
+
+    torch_onnx_minimum_version = version.parse("1.11")
+
+    @property
+    def inputs(self) -> Mapping[str, Mapping[int, str]]:
+        return OrderedDict(
+            [
+                ("pixel_values", {0: "batch", 1: "num_channels", 2: "height", 3: "width"}),
+            ]
+        )
+
+    @property
+    def atol_for_validation(self) -> float:
+        return 1e-4
+
+    @property
+    def default_onnx_opset(self) -> int:
+        return 12

src/transformers/onnx/features.py

@@ -456,6 +456,12 @@ class FeaturesManager:
             "token-classification",
             onnx_config_cls="models.roformer.RoFormerOnnxConfig",
         ),
+        "segformer": supported_features_mapping(
+            "default",
+            "image-classification",
+            "semantic-segmentation",
+            onnx_config_cls="models.segformer.SegformerOnnxConfig",
+        ),
         "squeezebert": supported_features_mapping(
             "default",
             "masked-lm",

tests/onnx/test_onnx_v2.py

@@ -216,6 +216,7 @@ PYTORCH_EXPORT_MODELS = {
     ("perceiver", "deepmind/vision-perceiver-conv", ("image-classification",)),
     ("longformer", "allenai/longformer-base-4096"),
     ("yolos", "hustvl/yolos-tiny"),
+    ("segformer", "nvidia/segformer-b0-finetuned-ade-512-512"),
 }
 
 PYTORCH_EXPORT_WITH_PAST_MODELS = {