ultralytics 8.0.160 Classify dataset scanning and caching (#4502)

ultralytics/data/utils.py

@@ -57,6 +57,31 @@ def exif_size(img: Image.Image):
     return s
 
 
+def verify_image(args):
+    """Verify one image."""
+    im_file, prefix = args
+    # Number (found, corrupt), message
+    nf, nc, msg = 0, 0, ''
+    try:
+        im = Image.open(im_file)
+        im.verify()  # PIL verify
+        shape = exif_size(im)  # image size
+        shape = (shape[1], shape[0])  # hw
+        assert (shape[0] > 9) & (shape[1] > 9), f'image size {shape} <10 pixels'
+        assert im.format.lower() in IMG_FORMATS, f'invalid image format {im.format}'
+        if im.format.lower() in ('jpg', 'jpeg'):
+            with open(im_file, 'rb') as f:
+                f.seek(-2, 2)
+                if f.read() != b'\xff\xd9':  # corrupt JPEG
+                    ImageOps.exif_transpose(Image.open(im_file)).save(im_file, 'JPEG', subsampling=0, quality=100)
+                    msg = f'{prefix}WARNING ⚠️ {im_file}: corrupt JPEG restored and saved'
+        nf = 1
+    except Exception as e:
+        nc = 1
+        msg = f'{prefix}WARNING ⚠️ {im_file}: ignoring corrupt image/label: {e}'
+    return im_file, nf, nc, msg
+
+
 def verify_image_label(args):
     """Verify one image-label pair."""
     im_file, lb_file, prefix, keypoint, num_cls, nkpt, ndim = args