Development of nano-satellite - image processing module

• Main Author: Kanika Bansal.
• Other Authors: School of Computer Engineering
• Format: Final Year Project
• Language: English
• Published: 2012
• Subjects: DRNTU::Engineering::Computer science and engineering::Computing methodologies::Image processing and computer vision
• Online Access: http://hdl.handle.net/10356/48853
• Institution: Nanyang Technological University

Velox-I is the premier nano-satellite being designed and built by the students of Nanyang Technological University and will be deployed into the Low Earth Orbit (LEO) in 2013. One of the objectives of the Velox-I mission is Earth observation. For this it is equipped with a CMOS Digital Image Sensor which will be used to provide high-resolution images of the Earth. These images are then sent to the Ground station using UHF and VHF signals by the satellite’s Communication Module. However, a satellite can only set up a downlink or uplink when it is in view of a ground station. If a LEO satellite passes directly over a ground station, it will be in view for about fifteen minutes only. Due to this small communication window combined with the limited downlink and uplink speed, only very limited data can be exchanged. Therefore, this project aims to implement a solution for compressing the captured images on-board the satellite itself. Compression would lead to a smaller size of image data and which would enable transfer of more information. The scope of this project includes: 1. Converting the RAW Image data into a standard readable format. 2. Development of an image compression algorithm to convert the large Image Data into a smaller image format with minimal compromise on the quality. 3. Building a testing framework in order to test this algorithm with the standard test images (E.g.: Lena) and satellite images. 4. Comparison of results obtained with different compression parameters and also with the existing conversion softwares available (E.g.: GIMP’s JPEG Converter). The JPEG Image format is used to solve the requirements of readability and compression. It is most suitable as it allows the user to control extent of compression. This project therefore involved development of a RAW to JPEG converter for the Renesas SH 7216 Microcontroller (which is used for interfacing with the camera). The developed converter transforms greyscale, RAW images into greyscale, JPEG images. The testing of the converter is to determine the optimal settings for the compression parameters, the constraints on input image and the time required for conversion.