sc_dsp_transforms

Stable release:	unreleased
Status:	draft
Maintainer:	https://github.com/henkmuller
Description:	DCT, FFT, and other transforms

Key Features

DCT Functionality:

• Basic quantising DCT for JPEG compression
• Basic Huffman encoder for JPEG encoder
• Access functions to compress a series of blocks.
• Example app to compress a PBM file into a JPEG file (PBM because that uses little memory to store).

FFT Functionality:

• Forward complex FFT
• Inverse complex FFT
• Forward real FFT
• Inverse real FFT
• Example app that performs forwards and inverse FFT in sequence

To Do

• Interface DCT with a camera.

Firmware Overview

The purpose of this repo is to collect a series of algorithms to perform transforms on data, such as FFT, DCT, etc.

There are three modules in the repo:

• module_dct_jpeg: forward quantising DCT. The process requires patches of 8x8 integer values, and in situ replace this with 8x8 transformed and quantised patches.
• module_huffman_jpeg: Huffman encode for JPEG images (this may have to go in a different repo). The process requires patches of 8x8 integer values, and streams bits out over a (streaming) channel.
• module_fft_simple: complex FFT (size must be a power of 2), and real FFT (two arrays of identical length that must both be a power of 2).

Known Issues

• This repo contains, for testing purposes, code from the JPEG library. This is not covered by LICENSE.TXT but has its own original LICENSE in an accompanying README file.

Required Repositories

• xcommon git@github.com:xcore/xcommon.git

Support

None at present