Browsing by Author "Benderli,O."

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Citation - Scopus: 5
Gezgin & Gezgin-2: Adaptive Real-time İmage Processing Subsystems For Earth Observing Small Satellites
(2006) Ismailoǧlu,N.; Benderli,O.; Yeşil,S.; Sever,R.; Okcan,B.; Şengül,O.; Öktem,R.; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
GEZGİN and GEZGİN-2 are real-time multi-spectral image processing subsystems developed for BİLSAT-1 and RASAT satellites respectively, the first two earth observing small satellites of Turkey, Main functionality of these subsystems is to compress in real-time multi-spectral images received concurrently from imagers, using JPEG2000 Image Compression algorithm. The compression features are controlled through user-supplied parameters uploaded in-orbit, so that the compression rate could be adapted to bandwidth, image quality and other mission requirements. GEZGİN employs both reconfigurable hardware and a DSP processor for image processing, where as the more advanced GEZGİN-2 contains full integration of the JPEG2000 processing path plus other image pre-processing features on reconfigurable hardware, hence offering increased performance and full re-configurability in orbit. Both systems demonstrate space-tailored architectures for implementing image processing functions where adaptability becomes the crucial issue determining robustness, flexibility and survivability of the system. © 2006 IEEE.
Citation - Scopus: 11
Gezgi̇n-2: an Advanced Image Processing Subsystem for Earth-Observing Small Satellites
(2005) Ismailoǧlu,N.; Benderli,O.; Yeşil,S.; Sever,R.; Okcan,B.; Öktem,R.; Chemical Engineering; 06. School Of Engineering; 01. Atılım University
GEZGİN-2 is a real-time image processing subsystem, currently being developed for RASAT, the second small satellite to be launched by TÜBİTAK-BİLTEN, in 2007. It is an advanced version of the GEZCİN payload, implementing JPEG 2000 image compression algorithm and currently flying on the BİLSAT-1 satellite. The main enhancements in GEZGİN-2 are the integration of the full processing path of JPEG 2000 algorithm in a single Field Programmable Gate Array (FPGA) for increased processing performance and high speed data links complying with the ESA Spacewire standard, for data transfer at a rate of 100 Mbps. In addition to JPEG2000, GEZGIN-2 facilitates image pre-processing for cloud/sea detection and image/data encryption implemented on a daughter-board called GÖLGE. As in GEZGİN, GEZGİN-2 allows for adjustment of compression ratio for different mission times by means of run-time supplied parameters and full reconfigurability in orbit. © 2005 IEEE.
Citation - Scopus: 2
Improving Compression Ratio for Satellite Transmission by Use of Cloud Extraction
(2005) Oktem,R.; Benderli,O.; Ismailoǧlu,N.; 01. Atılım University
This paper presents an alternative approach to JPEG 2000 based ROI coding, for use on-board satellite image compression. The proposed method works in the wavelet domain and modifies the wavelet coefficients in a way to allocate fewer bits for cloud-covered areas. This approach improves compression ratio and/or improves the quality of un-cloud-covered areas. The algorithm is implemented with pixel based and codeblock based schemes. Pixel based scheme can be embedded into any wavelet transform based codec. Both schemes allow packing of the coefficients into a fully JPEG2000 decoder compatible bitstream as soon as a codeblock is formed. The performance of the proposed schemes are demonstrated by tests on real satellite images acquired by BILSAT I.