Scalable Frame to Block Based Automatic Converter for Efficient Embedded Vision Processing

A typical digital signal processor (DSP) uses hierarchical memory to handle the trade-off between cost and speed. It has a fast on-chip memory with data-access rates similar to the DSP´s processing rate but it is not large enough to hold the entire Image data. Image buffers typically reside in the larger external memory like DDR whose data access rate is ~4-6X slower than the processor rate. Cache or direct memory access (DMA) mechanisms are used to improve the slow access rate of external memory using the internal memory. Optimizing an embedded processing application to be efficient for such hierarchical memory systems requires block-based algorithm design. This is usually accomplished by manually re-designing the code. This effort requires several man months and DSP expertise. In this paper, we automate this process and demonstrate a performance improvement of ~2-4X over conventional frame level processing. We believe that the proposed solution is novel in the sense that it is fully automated and scalable to any memory size and speed. We use a compiler assisted parser to extract the relevant function parameters and use them to re-target the code to be block-based and handle memory management automatically. This is an offline code generation process with self-verification. We have implemented and tested the parser for Texas Instruments (TI) C6000 DSPs but the method is generic to work with any processor core.