update angle doc

doc/doc_ch/angle_class.md

@@ -4,6 +4,10 @@
 文字检测之后得到的文本行图片经过仿射变换之后送入识别模型，此时只需要对文字进行一个0和180度的角度分类，因此PaddleOCR内置的
 文字角度分类器**只支持了0和180度的分类**。如果想支持更多角度，可以自己修改算法进行支持。
 
+0和180度数据样本例子：
+
+![](../imgs_results/angle_class_example.jpg)
+
 ### 数据准备
 
 请按如下步骤设置数据集：

doc/doc_en/angle_class_en.md

@@ -4,6 +4,9 @@
 The angle classification is used in the scene where the image is not 0 degrees. In this scene, it is necessary to perform a correction operation on the text line detected in the picture. In the PaddleOCR system,
 The text line image obtained after text detection is sent to the recognition model after affine transformation. At this time, only a 0 and 180 degree angle classification of the text is required, so the built-in PaddleOCR text angle classifier **only supports 0 and 180 degree classification**. If you want to support more angles, you can modify the algorithm yourself to support.
 
+Example of 0 and 180 degree data samples：
+
+![](../imgs_results/angle_class_example.jpg)
 ### DATA PREPARATION
 
 Please organize the dataset as follows: