Image compression with the Fast Walsh-Hadamard Transform (FWHT) has a long history, dating back to the 1960s and 1970s. Here's a quick rundown:
The Idea: FWHT, like other transforms (e.g., Fourier), breaks down an image into simpler components. The key advantage of FWHT is its computational efficiency. It uses only additions and subtractions, making it faster than other transforms involving multiplications.
Early Use: Space agencies like NASA used FWHT for compressing images from space probes due to this speed advantage.
Current Use: While not the most common method today (often surpassed by DCT - Discrete Cosine Transform), FWHT is still explored for image compression, particularly due to its:
Speed
Ability to achieve good compression ratios for the lower frequency components, struggles with the higher frequency components compared to say the jpeg algorithm.
Intermediate calculations in the WHT have wavelet like properties and can be used to achieve higher compression ratios.Â