add gussian tresold for python to get correct result from captured image

app/src/main/python/preprosessgreyscale.py

 import numpy as np
 import cv2
-from PIL import Image
+from PIL import Image, ImageEnhance
 import base64
 import io
 
@@ -9,8 +9,17 @@ def main(data):
     np_data = np.fromstring(decoded_data,np.uint8)
     img = cv2.imdecode(np_data,cv2.IMREAD_UNCHANGED)
     img_gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
-    pil_im = Image.fromarray(img_gray)
 
+
+    kernel = np.ones((1, 1), np.uint8)
+    pil_im = cv2.dilate(img_gray, kernel, iterations=1)
+    pil_im = cv2.erode(pil_im, kernel, iterations=1)
+
+   # pil_im = cv2.adaptiveThreshold(cv2.medianBlur(pil_im, 5), 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, cv2.THRESH_BINARY, 31, 5)
+    pil_im = cv2.threshold(cv2.GaussianBlur(pil_im, (9, 9), 0), 0, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)[1]
+
+
+    pil_im = Image.fromarray(pil_im)
     buff = io.BytesIO()
     pil_im.save(buff,format="PNG")
     img_str = base64.b64encode(buff.getvalue())