Fix hapi transform bug (#26738)

* fix bug

python/paddle/incubate/hapi/tests/test_transforms.py

@@ -64,6 +64,11 @@ class TestTransforms(unittest.TestCase):
 
         self.do_transform(trans)
 
+    def test_normalize(self):
+        normalize = transforms.Normalize(mean=0.5, std=0.5)
+        trans = transforms.Compose([transforms.Permute(mode='CHW'), normalize])
+        self.do_transform(trans)
+
     def test_trans_resize(self):
         trans = transforms.Compose([
             transforms.Resize(300, [0, 1]),
@@ -165,7 +170,7 @@ class TestTransforms(unittest.TestCase):
         fake_img = np.random.rand(500, 400, 3).astype('float32')
         fake_img_gray = trans_gray(fake_img)
 
-        np.testing.assert_equal(len(fake_img_gray.shape), 2)
+        np.testing.assert_equal(len(fake_img_gray.shape), 3)
         np.testing.assert_equal(fake_img_gray.shape[0], 500)
         np.testing.assert_equal(fake_img_gray.shape[1], 400)
 

python/paddle/incubate/hapi/vision/transforms/functional.py

@@ -16,6 +16,7 @@ import sys
 import collections
 import random
 import math
+import functools
 
 import cv2
 import numbers
@@ -31,6 +32,23 @@ else:
 __all__ = ['flip', 'resize', 'pad', 'rotate', 'to_grayscale']
 
 
+def keepdims(func):
+    """Keep the dimension of input images unchanged"""
+
+    @functools.wraps(func)
+    def wrapper(image, *args, **kwargs):
+        if len(image.shape) != 3:
+            raise ValueError("Expect image have 3 dims, but got {} dims".format(
+                len(image.shape)))
+        ret = func(image, *args, **kwargs)
+        if len(ret.shape) == 2:
+            ret = ret[:, :, np.newaxis]
+        return ret
+
+    return wrapper
+
+
+@keepdims
 def flip(image, code):
     """
     Accordding to the code (the type of flip), flip the input image
@@ -62,6 +80,7 @@ def flip(image, code):
     return cv2.flip(image, flipCode=code)
 
 
+@keepdims
 def resize(img, size, interpolation=cv2.INTER_LINEAR):
     """
     resize the input data to given size
@@ -103,6 +122,7 @@ def resize(img, size, interpolation=cv2.INTER_LINEAR):
         return cv2.resize(img, size[::-1], interpolation=interpolation)
 
 
+@keepdims
 def pad(img, padding, fill=(0, 0, 0), padding_mode='constant'):
     """Pads the given CV Image on all sides with speficified padding mode and fill value.
 
@@ -193,6 +213,7 @@ def pad(img, padding, fill=(0, 0, 0), padding_mode='constant'):
     return img
 
 
+@keepdims
 def rotate(img,
            angle,
            interpolation=cv2.INTER_LINEAR,
@@ -266,6 +287,7 @@ def rotate(img,
     return dst.astype(dtype)
 
 
+@keepdims
 def to_grayscale(img, num_output_channels=1):
     """Converts image to grayscale version of image.
 

python/paddle/incubate/hapi/vision/transforms/transforms.py

@@ -505,7 +505,7 @@ class Normalize(object):
             mean = [mean, mean, mean]
 
         if isinstance(std, numbers.Number):
-            mean = [std, std, std]
+            std = [std, std, std]
 
         self.mean = np.array(mean, dtype=np.float32).reshape(len(mean), 1, 1)
         self.std = np.array(std, dtype=np.float32).reshape(len(std), 1, 1)