SAR 영상 품질 분석을 위한 시뮬레이터 설계 및 구현
- 발행기관 아주대학교
- 지도교수 김재현
- 발행년도 2015
- 학위수여년월 2015. 2
- 학위명 석사
- 학과 및 전공 일반대학원 우주계측정보공학
- 실제URI http://www.dcollection.net/handler/ajou/000000019234
- 본문언어 한국어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
본 논문에서는 영상 레이다(SAR:SyntheticApertureRadar)의 영상을 형성하고 형성된 영상의 품질을 매트랩을 이용하여 분석하였다.영상 레 이다는 전자파를 이용하여 기상 조건에 상관없이 전천후로 지구를 관측하 는 고해상도 능동 센서이다.영상레이다는 광학 영상과 달리 복잡한 처리 과정을 거쳐서 영상이 형성되기 때문에 시스템의 설계와 운용 변수가 영 상의 품질에 직접적인 영향을 끼친다.본 논문에서는 영상레이다 시스템 설계 사양의 성능을 시험해 볼 수 있는 시뮬레이터를 제시하였다.제시한 시뮬레이터에서는 영상레이다의 영상 형성 알고리즘 구현하고,생성한 원 시 신호 데이터로부터 영상 품질을 분석하여 시뮬레이터의 신뢰성을 분석 하고,설계 사양에 적합한 요소들을 도출한다. 구현된 영상 형성 시뮬레이터는 원시 신호 생성,거리 압축,거리 보상, 방위 압축,임펄스 응답 함수 분석의 5단계로 나누어서 수행하였다.원시 신호 생성은 설계 파라미터의 입력을 받아 원시 신호를 생성하며,거리 압축 단계는 원시 신호의 거리 방향을 주파수 영역으로 변환하고 변환한 거리 신호와 주파수 영역의 거리 기준 함수를 상관시킨 후 결과를 시간영 역으로 역 변환시키는 과정이다.거리보정단계는 방위 방향을 주파수 영 역으로 변환하여 거리-도플러 영역에서 거리 보간 처리를 하여 보정한다. 방위 압축 단계는 보정이 완료된 데이터를 방위 기준 함수와 정합 함수링 한 결과를 시간 영역으로 역변환하게 된다.시간영역을 주파수 영역으로 변환 및 역변환 하는 과정은 FFT 및 IFFT 로 수행하였다. 영상 레이다 파라미터 및 오차 변화에 따른 영상 품질을 분석하였다.고 해상도 일수록 방위 FM율의 정보는 중요하며,플랫폼의 속도 벡터,거리 벡터로부터 정확한 추정이 선행되어야 한다.또한 윈도우 함수에 대한 영상의 성능을 분석하였다.윈도우 함수는 PSLR 성능을 향상시키지만,해 상도가 낮아지는 상충관계가 있어 영상 품질의 연관성을 분석하였다. 제안한 윈도우 함수가 부엽을 효과적으로 제거함으로써 기존의 윈도우 함수보다 낮아진 부엽에 비해 높은 해상도를 갖는 것을 확인하였다. 영상 레이다의 설계 변수에 따른 영상 품질을 분석함으로써 고해상도 영 상 레이다의 성능 요구 조건을 정립할 수 있을 것으로 기대되며,영상 레 이다 처리 기술과 영상 품질에 대한 성능 분석 및 연구에 기여가 있을 것 으로 기대된다.
more목차
제 1장 서 론 ········································································································1
제 2장 SAR 영상 형성 알고리즘 ·····································································3
제 1절 원시 데이터 ··························································································4
제 2절 거리압축 ································································································5
제 3절 거리 셀 이동 보상 ··············································································6
제 4절 방위압축 ································································································9
제 3장 위성 SAR 영상 형성 알고리즘의 구현 ···········································11
제 1절 위성 SAR 신호발생 모델 정립 ·····················································11
제 2절 위성 SAR 점 표적 신호 발생 ·······················································13
제 1항 영상 레이다 송신 신호 발생 ······················································13
제 2항 수신신호에 의한 점표적 신호 발생 ··········································16
제 3절 영상형성 알고리즘 구현 ··································································19
제 1항 원시 데이터 생성 ··········································································21
제 2항 거리압축 ··························································································25
제 3항 거리 셀 이동보상 ·············································································28
제 4항 방위압축 ··························································································29
제 5항 임펄스 응답 함수(IRF)특성 분석 ············································31
제 4장 SAR 영상 품질 분석 ···········································································37
제 1절 RCMC 성능 분석 ·············································································38
제 2절 방위FM율 오차 분석 ·······································································41
제 3절 윈도우 함수에 따른 영상 분석 ······················································46
제 5장 결론 ··········································································································52
참고 문헌 ················································································································54
ABSTRACT··········································································································57
