The Research And Realization Of Embedded Still Image Display System Based On ARM

JPEG is a kind of image encoding and decoding technique used mostwidely in the still image field to save and transmit the image informationnowadays. With the development of embedded technique, JPEG imageencoding and decoding technique has been used in many embedded systems,accordingly many embedded products appear, such as multimedia digitalcamera, and palmtop computer etc. At present the special integrated circuitASIC is often adopted to implement JPEG image encoding and decoding.The integrated level of this method is high and easy to realize, but its cost ishigh and it is difficult to upgrade and develop. Another more flexiblescheme is based on a high-performance processor such as ARM, DSP and soon, and all kinds of optimization algorithm are used to implement JPEGimage encoding and decoding. The method makes the system upgrading andfunction expanding realized through the software, which has lower cost thanhardware upgrade and has high flexibility and adaptability. The researchtopic of this article is "The Research and Realization of Still Image DisplaySystem Based on ARM" in which based on ARM hardware platform, thesoftware program is adopted to implement JPEG image decoding anddisplay.JPEG standard is introduced firstly in the paper then based on ARMprocessor S3C44BOX which come from SAMSUNG, a hardware processingplatform used to finish still image decoding and display has been designed.According to the hardware platform, bottom driver program and displaymodule program have been designed, which provide the software andhardware foundation for realizing the embedded image processing systemfinally. Further analyses and investigations have been done on the decoding process of JPEG Baseline system. The process of JPEG image decoding ismade up of five parts: tag code information processing, entropy decoding,dequantization, inversed discrete cosine transform and color spaceconverter. Because of inversed discrete cosine transform costing the mostquantity of time in the process of decoding, we adopt at row and columnmethod and convert 8×8 two-dimensional inversed discrete cosine transforminto 8 point one-dimensional inversed discrete cosine transform, whichrealizes inversed discrete cosine transform algorithm with high efficiencyand speed. Finally JPEG still image decoding and display processing systemhas been realized based on this hardware platform. In the end the fartheroptimization has been done to the decoding program from the aspects ofhardware characteristic of S3C44B0X and C program structure. Through thetest of decoding result to image quality and speed, the system can reach therequirement of image reconfiguration and the target of real-time decodingand display.