Add PPOCR-SIG description (PaddlePaddle#297)

Add PPOCR-SIG description

ppsigs/README.md

@@ -2,7 +2,16 @@
 
 PaddlePaddle projects have special interest groups operating in their repective ways. 
 
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+## PPOCR-SIG
+
+_SIG maintainer: [Evezerest](https://github.com/Evezerest)_
+
+PPOCR-SIG (PaddleOCR Special Interest Group) is committed to building a vibrant OCR community, and we welcome developers from all backgrounds to apply OCR to all walks of life in the spirit of open source, thereby improving our production efficiency.
+
+At present, PPOCR-SIG has created PPOCRLabel semi-automatic annotation tools, OCR vertical applications (such as electricity meters), OCR C# deployment, "Dive into OCR" e-book and other classic applications, which have made important contributions to the prosperity of the PaddleOCR community. These projects are contained in the PaddleOCR [Community Project](https://github.com/PaddlePaddle/PaddleOCR/blob/release/2.6/doc/doc_ch/thirdparty.md) 🏅️ . Specific PPOCR-SIG sub-direction tasks are presented in PaddleOCR [Community Event](https://github.com/PaddlePaddle/PaddleOCR/issues/4982) 🎁 ,which cover four categories, including documents, code, vertical models, and applications. This event is a leaderboard challenge for OCR community developers. 
+
+You can choose to join PPOCR-SIG by signing up for a the Community Event or [fill in the questionnaire](https://paddle.wjx.cn/vj/hoZnW83.aspx#) to discuss new insights with the group members.
+
 ## PPSIG Usability
 
 _SIG maintainer: [sunzhongkai588](https://github.com/sunzhongkai588)_
@@ -21,4 +30,3 @@ Links to previous activity:
   * [【The 4th activity】](https://github.com/PaddlePaddle/docs/issues/4920) ｜ [【The 3rd activity】](https://github.com/PaddlePaddle/docs/issues/4846)
   * [【The 2nd activity】](https://github.com/PaddlePaddle/Paddle/issues/40109) ｜ [【The 1st activity】](https://github.com/PaddlePaddle/Paddle/issues/38865)
 
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