remove unused images

ocr.py

@@ -85,7 +85,6 @@ class Recognizer:
     def preprocess(self, image, height, width, invert=False):
         src: np.ndarray = cv2.cvtColor(image, cv2.COLOR_RGBA2GRAY)
         src = (255 - src) if invert else src
-        cv2.imwrite("a.png", src)
 
         ratio = float(src.shape[1]) / float(src.shape[0])
         tw = int(height * ratio)