deltack

deltack can be used to correct isolated instances of problems with camera attitude. It adjusts camera orientation in the labels of a single Isis 3 cube (resection). Like jigsaw, it works on both framing cameras and line scanners. The user must supply a latitude/longitude for at least one sample/line coordinate in the image. Angles 1 and 2 of the camera orientation stored in the cube labels will be adjusted to align the coordinate with the entered latitude/longitude. To solve for all three camera angles, select the TWIST option. A second coordinate point and desired latitude/longitude must be entered if the TWIST option is used. deltack will adjust the camera orientation to align both points with their corresponding latitudes/longitudes with minimal residuals in sample and line. In order for deltack to work properly, the input cube must have been initialized with spiceinit using ATTACH="YES".

The camera pointing is updated using an iterative least-squares bundle adjustment. The number of iterations (MAXIT)and tolerance (SIGMA0) for convergence are input parameters to deltack. Solving for two angles only is similar to a translation of the image in sample and line. Solving for the twist as well will result in both a translation and a rotation.

deltack creates a set of two output files for analyzing the results. BUNDLEOUT.TXT provides an overall summary of the resection. It lists the user input parameters selected and tables of statistics for both the image and the point(s). RESIDUALS.CSV provides a table of the measured image coordinates and the final sample, line, and overall residuals in both millimeters and pixels.