Hiệu chuẩn và chế biến hình ảnh Điều này mang tính cách mạng công nghệ mới (một gần như có thể nói nghệ thuật đen) của viễn thám là cung cấp cho các nhà khoa học với tất cả các loại thông tin mới có giá trị để nuôi máy tính của họ - KF Weaver, 1969 GEORADIOMETRIC TÁC VÀ ỨNG PHÓ quang phổ Một thuật ngữ chung chung, quang phổ phản ứng, thường được dùng để tham khảo với năng lượng phát hiện được ghi nhận là các phép đo kỹ thuật số trong hình ảnh cảm biến từ xa (Lillesand và. | 4 Image Calibration and Processing This revolutionary new technology one might almost say black art of remote sensing is providing scientists with all kinds of valuable new information to feed their computers K. F. Weaver 1969 GEORADIOMETRIC EFFECTS AND SPECTRAL RESPONSE A generic term spectral response is typically used to refer to the detected energy recorded as digital measurements in remote sensing imagery Lillesand and Kiefer 1994 . Since different sensors collect measurements at different wavelengths and with widely varying characteristics spectral response is used to refer to the measurements without signifying a precise physical term such as backscatter radiance or reflectance. In the optical infrared portion of the spectrum there are five terms representing radiometric quantities radiant energy radiant density radiant flux radiant exitance and irradiance . These are used to describe the radiation budget of a surface and are related to the remote sensing spectral response Curran 1985 . When discussing image data the term spectral response suggests that image measurements are not absolute but are relative in the same way that photographic tone refers to the relative differences in exposure or density on aerial photographs. Digital image spectral response differs fundamentally from photographic tones though in that spectral response can be calibrated or converted to an absolute measurement to the extent that spectral response depends on the particular characteristics of the sensor and the conditions under which it was deployed. When all factors affecting spectral response have been considered the resulting physical measurement such as radiance in W m2 pm sr spectral reflectance in percentage or scattering coefficient in decibels is used. Consideration of the geometric part of the image analysis procedure typically follows here the task is the correct placement of each image observation on the ground in terms of Earth or map coordinates. It is well known that
