feat(mge/data): voc dataset supports detection

GitOrigin-RevId: f78bef3cd2ba895c2ec0ca1e0132737cf5a5cbd5

python_module/megengine/data/dataset/vision/voc.py

@@ -29,43 +29,47 @@ class PascalVOC(VisionDataset):
 
     supported_order = (
         "image",
-        # "boxes",
-        # "boxes_category",
+        "boxes",
+        "boxes_category",
         "mask",
         "info",
     )
 
     def __init__(self, root, image_set, *, order=None):
+        if ("boxes" in order or "boxes_category" in order) and "mask" in order:
+            raise ValueError("PascalVOC only supports boxes & boxes_category or mask, not both.")
+
         super().__init__(root, order=order, supported_order=self.supported_order)
 
-        voc_root = self.root
-        if not os.path.isdir(voc_root):
+        if not os.path.isdir(self.root):
             raise RuntimeError("Dataset not found or corrupted.")
 
         self.image_set = image_set
-        image_dir = os.path.join(voc_root, "JPEGImages")
-
-        # for segmentation
-        if "aug" in image_set:
-            mask_dir = os.path.join(voc_root, "SegmentationClass_aug")
+        image_dir = os.path.join(self.root, "JPEGImages")
+
+        if "boxes" in order or "boxes_category" in order:
+            annotation_dir = os.path.join(self.root, 'Annotations')
+            splitdet_dir = os.path.join(self.root, "ImageSets/Main")
+            split_f = os.path.join(splitdet_dir, image_set.rstrip("\n") + ".txt")
+            with open(os.path.join(split_f), "r") as f:
+                self.file_names = [x.strip() for x in f.readlines()]
+            self.images = [os.path.join(image_dir, x + ".jpg") for x in self.file_names]
+            self.annotations = [os.path.join(annotation_dir, x + ".xml") for x in self.file_names]
+            assert len(self.images) == len(self.annotations)
+        elif "mask" in order:
+            if "aug" in image_set:
+                mask_dir = os.path.join(self.root, "SegmentationClass_aug")
+            else:
+                mask_dir = os.path.join(self.root, "SegmentationClass")
+            splitmask_dir = os.path.join(self.root, "ImageSets/Segmentation")
+            split_f = os.path.join(splitmask_dir, image_set.rstrip("\n") + ".txt")
+            with open(os.path.join(split_f), "r") as f:
+                self.file_names = [x.strip() for x in f.readlines()]
+            self.images = [os.path.join(image_dir, x + ".jpg") for x in self.file_names]
+            self.masks = [os.path.join(mask_dir, x + ".png") for x in self.file_names]
+            assert len(self.images) == len(self.masks)
         else:
-            mask_dir = os.path.join(voc_root, "SegmentationClass")
-        splitmask_dir = os.path.join(voc_root, "ImageSets/Segmentation")
-        split_f = os.path.join(splitmask_dir, image_set.rstrip("\n") + ".txt")
-        with open(os.path.join(split_f), "r") as f:
-            self.file_names = [x.strip() for x in f.readlines()]
-        self.images = [os.path.join(image_dir, x + ".jpg") for x in self.file_names]
-        self.masks = [os.path.join(mask_dir, x + ".png") for x in self.file_names]
-
-        # TODO: for detection
-        # splitdet_dir = os.path.join(voc_root, "ImageSets/Main")
-        # split_f = os.path.join(splitdet_dir, image_set.rstrip("\n") + ".txt")
-        # with open(os.path.join(split_f), "r") as f:
-        #     self.file_names = [x.strip() for x in f.readlines()]
-        # self.images = [os.path.join(image_dir, x + ".jpg") for x in file_names]
-        # self.annotations = [os.path.join(annotation_dir, x + ".xml") for x in self.file_names]
-
-        # assert (len(self.images) == len(self.masks)) and (len(self.images) == len(self.annotations))
+            raise NotImplementedError
 
     def __getitem__(self, index):
         target = []
@@ -73,6 +77,19 @@ class PascalVOC(VisionDataset):
             if k == "image":
                 image = cv2.imread(self.images[index], cv2.IMREAD_COLOR)
                 target.append(image)
+            elif k == "boxes":
+                anno = self.parse_voc_xml(ET.parse(self.annotations[index]).getroot())
+                boxes = [obj["bndbox"] for obj in anno["annotation"]["object"]]
+                # boxes type xyxy
+                boxes = [(bb['xmin'], bb['ymin'], bb['xmax'], bb['ymax']) for bb in boxes]
+                boxes = np.array(boxes, dtype=np.float32).reshape(-1, 4)
+                target.append(boxes)
+            elif k == "boxes_category":
+                anno = self.parse_voc_xml(ET.parse(self.annotations[index]).getroot())
+                boxes_category = [obj["name"] for obj in anno["annotation"]["object"]]
+                boxes_category = [self.class_names.index(bc)-1 for bc in boxes_category]
+                boxes_category = np.array(boxes_category, dtype=np.int32)
+                target.append(boxes_category)
             elif k == "mask":
                 if "aug" in self.image_set:
                     mask = cv2.imread(self.masks[index], cv2.IMREAD_GRAYSCALE)
@@ -81,9 +98,6 @@ class PascalVOC(VisionDataset):
                     mask = self._trans_mask(mask)
                 mask = mask[:, :, np.newaxis]
                 target.append(mask)
-            elif k == "boxes":
-                boxes = self.parse_voc_xml(ET.parse(self.annotations[index]).getroot())
-                target.append(boxes)
             elif k == "info":
                 if image is None:
                     image = cv2.imread(self.images[index], cv2.IMREAD_COLOR)
@@ -128,7 +142,6 @@ class PascalVOC(VisionDataset):
         return voc_dict
 
     class_names = (
-        "background",
         "aeroplane",
         "bicycle",
         "bird",
@@ -151,7 +164,6 @@ class PascalVOC(VisionDataset):
         "tvmonitor",
     )
     class_colors = [
-        [0, 0, 0],
         [0, 0, 128],
         [0, 128, 0],
         [0, 128, 128],