Software JPEG for a 32-bit MCU with dual issue

This paper describes a new software solution for DCT-based JPEG image compression using a 32-bit microcontroller unit (MCU) with parallel execution (dual issue). Taking the constraints of the MCU hardware resources into consideration, various fast algorithms for DCT are investigated. As a result, it is concluded that the optimal fast algorithm for MCUs capable of parallel execution differs from the optimal algorithm for MCUs which do not support parallel execution. Comparing the number of JPEG image compression cycles using software on MCUs with and without parallel execution capability, it is concluded that the processing speed of the latter type of MCU is approximately 30% higher than the former type. When this former processing speed is applied to a 640/spl times/480 (VGA-size) YCbCr image in 4:2:2 format, compression can be performed in about 0.15 seconds (using a 100 MHz MCU with parallel execution capability).