Merge pull request #641 from FlyingQianMM/develop_qh

add note: only one-channel image is supported for CLAHE transform in doc

docs/apis/transforms/det_transforms.md

@@ -174,6 +174,8 @@ paddlex.det.transforms.CLAHE(clip_limit=2., tile_grid_size=(8, 8))
 ```
 对图像进行对比度增强。
 
+【注意】该数据增强只适用于灰度图。
+
 ### 参数
 
 * **clip_limit** (int|float): 颜色对比度的阈值，默认值为2.。

paddlex/cv/transforms/det_transforms.py

@@ -1070,7 +1070,7 @@ class CLAHE(DetTransform):
         """
         if im.shape[-1] != 1:
             raise Exception(
-                "Only the one-channel image is supported in the CLAHE operator, but recieved image channel is {}".
+                "Only the one-channel image is supported in the CLAHE transform, but recieved image channel is {}".
                 format(im.shape[-1]))
         clahe = cv2.createCLAHE(
             clipLimit=self.clip_limit, tileGridSize=self.tile_grid_size)