Relative radiometric correction of remote sensing images is a basic data preprocessing technique used to eliminate r adiometric problems in images such as non-uniformity

stripe noises

and defective lines. Over the past 30 years

numerous relative radiometric correction methods and algorithms have been developed. This situation brings up three questions.（1） What are the differences and relationships among these methods?（2）What are the characteristics of each method?（3） How is a suitable method selected? To answer these questions

the methods are first classified into three categories: calibration-based

scene-based

and c omprehensive methods. Second

the mathematical models of the three categories of methods are provided in the new classification system. Then

each method is introduced and compared with the others. Third

the applicability of the methods is comprehensively analyzed according to the following aspects: non-uniformity characteristics

geometric characteristics

sensor calibration

and the comprehensive characteristics of images. Suggestions on selecting a suitable method are provided

and an example of image correction is demonstrated. Finally

the research tendency and several existing problems of relative radiometric correction are analyzed.The computer criteria for signal and noises

the evaluation system

and the influence on subsequent absolute corrections require f urther studies.