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TitleThe Necessity of Exterior Orientation Parameters for the Rigorous Geometric Correction of MEIS-II Airborne Digital Images
AuthorBannari, A; Gibson, J R; Morin, D
SourceRemote Sensing Reviews vol. 16, no. 43102, 1997 p. 135-156,
Alt SeriesNatural Resources Canada, Contribution Series 20181176
PublisherInforma UK Limited
Mediapaper; on-line; digital
File formatpdf
Subjectsgeophysics; remote sensing
ProgramCanada Centre for Remote Sensing Divsion
AbstractRemote sensing is an essential element of the Canada Land Use Monitoring Program. The program sought the replacement, before 1991, of classical aerial photographs by remote sensing imagery (satellite or airborne) as the main source of data for land management (Wilson, 1986). In this sense, the Canada Centre for Remote Sensing (CCRS) has been involved over the last few years in a project for implementing an airborne multi-detector electro-optical imaging system (MEIS-II). The acceptance of airborne scanners has been slow over the years principally because of poor spatial resolution and distortions induced by aircraft motion. For addressing this geometric problem, CCRS has developed a rigorous correction method based on a fundamental photogrammetric principle (colinearity condition) and auxiliary navigation data (attitude, altitude and aircraft speed) measured in relation to time by an inertial navigation system (INS). The method can process images in monoscopy or stereoscopy (two flight lines or more, in which case, the method also uses the coplanarity condition). It uses primarily a low-order polynomial function for correcting auxiliary data based on the method of least squares and a few control points. The results are then used in the geometric correction procedure. In this study, we discuss the effect of geometric distortions caused by aircraft motion and we test two geometric correction methods. The first method is the one developed by CCRS mentioned above. The second method referred to as "classical" is based on a second order polynomial function. Moreover, we examine the effect of control point precision on the reliability of the geometric correction using geodetic points and other points derived from the 1: 20 000 topographical map. The results obtained show a noticeable difference between the two approaches tested. In view of the fact that it takes into consideration parameters related to viewing geometry (exterior orientation parameters), the photogrammetric method, based on the colinearity condition, and related to navigation data, results in precision in the order of one pixel with geodetic control points. The use of geodetic control points permits the elimination of the planimetric error characteristic of the topographical map. The polynomial method on the other hand provides precision which is in the order of five pixels whatever the type and precision of the control points.

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