The program works by converting the input text to binary and then modifying the brightness values of existing pixels to encode these binary values in the image. Keep in mind that the approach used for both encoding and reading data is extremely naive at the moment, and JPEG compression will likely destroy the high frequencies holding data if the image is reencoded.
Python 3 and Skikit are required.
Syntax: python3 imagesigner.py sign IMAGENAME "MESSAGE TO ENCODE" REPETITIONS, where REPETITIONS is the number of lines in the image the message is repeated. A value of -1 encodes the message on every line. Most common image file formats are accepted. Encoding images with more repetitions will result in a more accurate result as the chances of every repetition being unreadable is smaller, but will result in more visible stripes across the image.
For example, python3 imagesigner.py sign image.jpg "The quick brown fox jumps over the lazy dog" 32 encodes the phrase The quick brown fox jumps over the lazy dog in binary and writes it to 32 lines in the source image, image.jpg.
Syntax: python3 imagesigner.py read IMAGENAME. Again, most common image file formats are accepted.
For example, python3 imagesigner.py read image_signed.jpg tries to extract any encoded text from the source image, image_signed.jpg.
There are some other global config variables in the code. sensitivity is an integer that controls which color values are considered white. Higher values allow more pixels to be considered white. verbose toggles the printing of extra information. opacity controls how visible the encoded data is with respect to the original image.
This is a an experimental project but ideas are welcome.
This project is licensed under the Mozilla Public License 2.0. See LICENSE.md for details.