To prevent the OCR software from recognizing the CAPTCHA characters, we design a challenge which is possible to obfuscate the characteristic, shape and alphabet or number outline, but it is still able to be identified under human eye vision. By having the characters presented in 3-Dementional format as shown in the Figure 4 and Figure 5, dimension outline together with shading and shadow will confuse the OCR software hence it can reduce the recognition rate. Extruded alphanumeric characters can be identified by normal users as the 3D still display the letters or numbers in visible form.
Few text fonts and text size will be designed to allow Captcha to choose randomly each time it creates a new challenge. Angle and dimension of how the text is being display will be changed for every Captcha produced as well. This could avoid the OCR from having a standard input scanning pattern to identify the characters.
Random selection functions for color is also included in this design to prevent OCR from fixing a standard scanning algorithm. In addition, the distance between each characters will be minimized to avoid the OCR from identified the boundaries of each characters.
Few text fonts and text size will be designed to allow Captcha to choose randomly each time it creates a new challenge. Angle and dimension of how the text is being display will be changed for every Captcha produced as well. This could avoid the OCR from having a standard input scanning pattern to identify the characters.
Random selection functions for color is also included in this design to prevent OCR from fixing a standard scanning algorithm. In addition, the distance between each characters will be minimized to avoid the OCR from identified the boundaries of each characters.
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