C # verification code recognition practices

Summarize some of the recently learned knowledge.
Then, I wrote this small program.
The role of this applet is to identify a simple verification code.
 
The program runs as follows:

Language C #. Www.2cto.com
If you use C ++ to write data, it is no longer difficult to call the OpenCV library.
So use C # to implement your own handwriting algorithm and exercise it. Haha.

The recognition rate of the following verification codes reaches 100%.
Haha. Believe it? Download it and try again ..
 
:
:
 
:
(Note: To identify this verification code, you must select "Point 1" on the program interface. Otherwise, the Verification Code cannot be recognized)
 
Considering that such a program requires a lot of experiments and tests
For convenience, I used the image download function in the program,
You can download the verification code to identify it.
Of course, this is the advantage of C.
If C ++ does not use a third-party library,
It is troublesome to directly download images through Socket Http requests.
 
This program also has a certain recognition rate for the verification code below. But very low
:
The reason is as follows.