diff --git a/main.py b/main.py
index 81f53cc..2a7ac16 100644
--- a/main.py
+++ b/main.py
@@ -1,7 +1,7 @@
 import os
 
 from study import study
-
+from utility import md5
 
 def getAccounts():
     result = []
diff --git a/study.py b/study.py
index 2f0fcff..6af24bb 100644
--- a/study.py
+++ b/study.py
@@ -20,6 +20,8 @@ def study(username, password, ua):
             touch = bjySession.get(url="https://m.bjyouth.net/site/login")
             capUrl = "https://m.bjyouth.net" + re.findall(
                 r'src="(/site/captcha.+)" alt=', touch.text)[0]
+            if "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQD5uIDebA2qU746e/NVPiQSBA0Q" not in touch.text:
+                print("记录的公钥没有出现")
             capText = cap_recognize(bjySession.get(url=capUrl).content)
             # print(f'验证码识别: {capText}')
             login_r = bjySession.post('https://m.bjyouth.net/site/login',
diff --git a/utility.py b/utility.py
index 060b1a0..5e7480e 100644
--- a/utility.py
+++ b/utility.py
@@ -14,6 +14,11 @@ def encrypt(t):
     cipher_text = b64encode(cipher.encrypt(t.encode()))
     return cipher_text.decode()
 
+def md5(s):
+    import hashlib
+    m = hashlib.md5()
+    m.update(s.encode())
+    return m.hexdigest()
 
 def cap_recognize(cap):
     return DdddOcr().classification(denoise(cap))
@@ -22,25 +27,45 @@ def cap_recognize(cap):
 def denoise(cap):
     img = Image.open(BytesIO(cap))
     steps = ((1, 1), (1, 0), (1, -1), (0, 1), (0, -1), (-1, 1), (-1, 0), (-1, -1))
-    _PX_WHITE = (250, 250, 250)
+    _PX_BACKGROUND = (250, 250, 250)
+    _PX_TARGET = (250, 0, 0)
     threshold, repeat = 7, 2
 
     for _ in range(repeat):
         for j in range(img.width):
             for i in range(img.height):
                 px = img.getpixel((j, i))
-                if px == _PX_WHITE:
+                if px == _PX_BACKGROUND:
                     continue
                 count = 0
                 if px[0] < px[1] + px[2]:
                     count = 2
                 for x, y in steps:
                     if 0 <= j + x < img.width and 0 <= i + y < img.height:
-                        if img.getpixel((j + x, i + y)) == _PX_WHITE:
+                        if img.getpixel((j + x, i + y)) == _PX_BACKGROUND:
                             count += 1
                 if count >= threshold:
-                    img.putpixel((j, i), _PX_WHITE)
+                    img.putpixel((j, i), _PX_BACKGROUND)
+                else:
+                    img.putpixel((j, i), _PX_TARGET)
 
     buf = BytesIO()
     img.save(buf, format='PNG')
     return buf.getvalue()
+
+if __name__ == '__main__':
+    import requests
+    import re
+    bjySession = requests.session()
+    bjySession.timeout = 5  # set session timeout
+    touch = bjySession.get(url="https://m.bjyouth.net/site/login")
+    capUrl = "https://m.bjyouth.net" + re.findall(
+        r'src="(/site/captcha.+)" alt=', touch.text)[0]
+    cap1 = bjySession.get(url=capUrl).content
+    cap2 = denoise(cap1)
+
+    img = Image.open(BytesIO(cap1))
+    img.show()
+
+    img = Image.open(BytesIO(cap2))
+    img.show()
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