Graphics and Color

• Hex nostalgia, on encoding 1-bit pixels

• A sign that uses 1 bit per pixel

   

• Additive color

• Color depth

• 4-bit color demo

• 24-bit color demo

• Pixels in the BAM sign – full image · zoomed in

• Similar subpixelization of an image, just like the BAM sign.

  

  Original Bart

  Click on Subpixelized Bart and zoom in with control-plus. You’ll see that the yellow regions of the image are made up only of red and green lights.

• What the hex color guessing game

Steganography

 <<  Shift 0: sample pixel 727F1F         = 01110010 01111111 00011111  >> 

More steganography

In class, I noted that the image-within-image steganography technique worked best with photographs, where there are subtle gradations of color everywhere. If you start with a cartoon-style image, with large solid blocks of unvarying color, it’s easier to see the hint of the inner image. Here is an example. Depending on how good your monitor and eyes are, you can make out some outlines of the 6-bit hidden image, before shifting the pixel values.

See also: C++ source code of my steganography program.

 <<  Shift 0: sample pixel E81C35         = 11101000 00011100 00110101  >> 

It’s maybe even a little more visible when the inner image is a cartoon too.

 <<  Shift 0: sample pixel EC213A         = 11101100 00100001 00111010  >>