From 6e5a79bb4eca77062fd4426f038eb8b0c9c3c89e Mon Sep 17 00:00:00 2001 From: Panagiotis Tigas Date: Thu, 16 Nov 2017 01:02:39 +0000 Subject: [PATCH] Update README.md --- README.md | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/README.md b/README.md index ff92b22..ca5deca 100644 --- a/README.md +++ b/README.md @@ -11,11 +11,11 @@ In this example we are going to use the following images. First of all, a fixed size (monospace) font has been used. This makes extracting the letters and using them as masks to check each digit, one by one, very easy. Also, the alphabet is simple lowercase hexadecimal letters. Thus, we had to extract only 16 letters. -The first part was to to extract all the letters. To achieve that, first of all we sampled several images so as to be sure that the images we have contains all the 16 letters. Then, using a simple image editor we cropped all the letters, one by one. We had to be careful so all the letters be aligned properly. Here is the final mask. +The first part was to to extract all the letters. To achieve that, first of all we sampled several images so as to be sure that the images we have contains all the 16 letters. Then, using a simple image editor we cropped all the letters, one by one. You have to be very careful so all the letters be aligned properly. Here is the final mask. ![](/letters.bmp?raw=true "letters") -Now we can focus on the CAPTCHA. As you can notice there is some noise which we have to remove (lines and stuff). After playing with several techniques we finally ended to the following. We turned the image to greyscale. Then we used a threshold to remove some of the noise. Here is the example after the filtering (cropping also applied). +Now we can focus on the CAPTCHA. As you can notice there is some noise which we have to remove (lines and stuff). After playing with several techniques we finally ended to the following. We turned the image to greyscale, then used a threshold to remove some of the noise. Here is the example after the filtering (cropping also applied). ![](/filtered.jpg?raw=true "source")