A Q-Coder algorithm with carry free addition

The Q-Coder algorithm is a very efficient compression technique for bi-level images based on the arithmetic coding. The paper presents a new and fast version of the Q-Coder algorithm in which the carry-propagated adders have been replaced by carry-save adders. In this way, all the additions can be performed with a delay time of a single fill adder, independently of the length of the operands. The compression method is faster than the traditional Q-Coder algorithm with an almost unnoticeable increasing of the hardware requirements.