Text Recognition: Add script to evaluate text recognition by ICDAR2003 (#71)

* update readme

* add another script

* revise details for this pr

README.md

@@ -2,11 +2,24 @@
 
 An End-to-End Trainable Neural Network for Image-based Sequence Recognition and Its Application to Scene Text Recognition
 
+Results of accuracy evaluation with [tools/eval](../../tools/eval) at different text recognition datasets.
+
+| Model name   | ICDAR03(%) | IIIT5k(%) | CUTE80(%) |
+|--------------|------------|-----------|-----------|
+| CRNN_EN      | 81.66      | 74.33     | 52.78     |
+| CRNN_EN_FP16 | 82.01      | 74.93     | 52.34     |
+| CRNN_CH      | 71.28      | 80.90     | 67.36     |
+| CRNN_CH_FP16 | 78.63      | 80.93     | 67.01     |
+
+\*: 'FP16' stands for 'model quantized into FP16'.
+
 Note:
 - Model source:
     - `text_recognition_CRNN_EN_2021sep.onnx`: https://docs.opencv.org/4.5.2/d9/d1e/tutorial_dnn_OCR.html (CRNN_VGG_BiLSTM_CTC.onnx)
+    - `text_recognition_CRNN_CH_2021sep.onnx`: https://docs.opencv.org/4.x/d4/d43/tutorial_dnn_text_spotting.html (crnn_cs.onnx)
     - `text_recognition_CRNN_CN_2021nov.onnx`: https://docs.opencv.org/4.5.2/d4/d43/tutorial_dnn_text_spotting.html (crnn_cs_CN.onnx)
 - `text_recognition_CRNN_EN_2021sep.onnx` can detect digits (0\~9) and letters (return lowercase letters a\~z) (view `charset_36_EN.txt` for details).
+- `text_recognition_CRNN_CH_2021sep.onnx` can detect digits (0\~9), upper/lower-case letters (a\~z and A\~Z), and some special characters (view `charset_94_CH.txt` for details).
 - `text_recognition_CRNN_CN_2021nov.onnx` can detect digits (0\~9), upper/lower-case letters (a\~z and A\~Z), some Chinese characters and some special characters (view `charset_3944_CN.txt` for details).
 - For details on training this model series, please visit https://github.com/zihaomu/deep-text-recognition-benchmark.
 
@@ -16,6 +29,7 @@ Note:
 - This demo uses [text_detection_db](../text_detection_db) as text detector.
 - Selected model must match with the charset:
     - Try `text_recognition_CRNN_EN_2021sep.onnx` with `charset_36_EN.txt`.
+    - Try `text_recognition_CRNN_CH_2021sep.onnx` with `charset_94_CH.txt`
     - Try `text_recognition_CRNN_CN_2021sep.onnx` with `charset_3944_CN.txt`.
 
 Run the demo detecting English:

charset_94_CH.txt

@@ -0,0 +1,94 @@
+0
+1
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+a
+b
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+m
+n
+o
+p
+q
+r
+s
+t
+u
+v
+w
+x
+y
+z
+A
+B
+C
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+F
+G
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+I
+J
+K
+L
+M
+N
+O
+P
+Q
+R
+S
+T
+U
+V
+W
+X
+Y
+Z
+!
+"
+#
+$
+%
+&
+'
+(
+)
+*
++
+,
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+/
+:
+;
+<
+=
+>
+?
+@
+[
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+^
+_
+`
+{
+|
+}
+~

crnn.py

@@ -54,7 +54,9 @@ class CRNN:
         rotationMatrix = cv.getPerspectiveTransform(vertices, self._targetVertices)
         cropped = cv.warpPerspective(image, rotationMatrix, self._inputSize)
 
-        if 'CN' in self._model_path:
+        # 'CN' can detect digits (0\~9), upper/lower-case letters (a\~z and A\~Z), and some special characters
+        # 'CH' can detect digits (0\~9), upper/lower-case letters (a\~z and A\~Z), some Chinese characters and some special characters
+        if 'CN' in self._model_path or 'CH' in self._model_path:
             pass
         else:
             cropped = cv.cvtColor(cropped, cv.COLOR_BGR2GRAY)