Research On Compression Methods Of Unmanned Aerial Vehicle's Image Sequence

The UAV (unmanned aerial vehicle) is playing a more important role in modem society. Many countries attach importance to the development of the UAV. One of most important use of the UAV is to achieve aerial spy and battlefield monitor. The spy information should be transmitted to the receive point in real time by radio. Due to the digital signal transmission have many merits such us high quality, strong anti-jamming ability, strong ability of keeping secret, and it can be transmitted with other information in the same channel, the UAV spy image signal is transmitted in digital signal. To get the high quality images is the requirement of UAV spying and monitor. But the UAV flying height is high, flying speed is very fast, the targets in the spy image always are very small, and have the big quantity, the relativity between the pixels in the frame is little, the image movement is full screen movement, the relativity between the frames is also little, the ordinary compress methods can not get the good effect in compressing the UAV image. Basing on the existing image and video coding standards, much research has been done in the key technology of image and video compression in this paper. By utilizing the traits of UAV image sequence, more effective compression methods are provided in this paper. In image coding, an embedded-coding image compression algorithm based on wavelet transform is implemented. The blocked and layered coding mode of this algorithm makes the coding steam robust for errors, and it is easy to be implemented in parallel hardware. This image coding algorithm is comparable to the JPEG2000 coding standard in the coding efficiency. In image sequence coding, base on the image coding algorithm, a new UAV image sequence coding scheme is proposed in this paper. In the scheme a new self-adapting motion estimation algorithm is introduced, it can deeply reduce the computational complexity, and greatly save the bit rate. The experiments show that this scheme has the little complexity and better effect than the H.264 standard, and is easy to be implemented in hardware. This scheme is also can be applied to the image sequence coding which have the approximate line movement model.