!8948 fix warpctc prec bug

From: @gengdongjie
Reviewed-by: @linqingke,@yingjy
Signed-off-by: @linqingke

model_zoo/official/cv/warpctc/src/dataset.py

@@ -67,6 +67,12 @@ def transpose_hwc2whc(image):
     return image
 
 
+def transpose_hwc2chw(image):
+    """transpose image from HWC to CHW"""
+    image = np.transpose(image, (2, 0, 1))
+    return image
+
+
 def create_dataset(dataset_path, batch_size=1, num_shards=1, shard_id=0, device_target='Ascend'):
     """
      create train or evaluation dataset for warpctc
@@ -91,7 +97,10 @@ def create_dataset(dataset_path, batch_size=1, num_shards=1, shard_id=0, device_
         c.TypeCast(mstype.int32)
     ]
     ds = ds.map(operations=image_trans, input_columns=["image"], num_parallel_workers=8)
+    if device_target == 'Ascend':
         ds = ds.map(operations=transpose_hwc2whc, input_columns=["image"], num_parallel_workers=8)
+    else:
+        ds = ds.map(operations=transpose_hwc2chw, input_columns=["image"], num_parallel_workers=8)
     ds = ds.map(operations=label_trans, input_columns=["label"], num_parallel_workers=8)
 
     ds = ds.batch(batch_size, drop_remainder=True)