Analysis of Streak-Camera Measurement Errors Caused by Misorientation of the Camera Slit with Recording Direction

摘要

Erroneous data are produced when we analyze streak or smear camera records in which the lack of perpendicularity between the camera slit and the recording direction is not considered. Generated velocity errors are either constant or variable, depending upon the orientation strategy used in analyzing the film. The size of these absolute errors is proportional to the slit misorientation angle or to the product of slit misorientation and the square of event velocity. To a first approximation, the relative velocity error, expressed as a decimal fraction, is equal to the slit misorientation angle in radians. When the degree of slit misorientation is unknown, film reading strategies are offered for minimizing absolute and relative errors. Unfortunately, slit misorientation also causes symmetrical phenomena to be recorded asymmetrically. Nevertheless, we can correct all aberrances with a simple function that restores the photographic measurements to their true displacement-time values. (ERA citation 08:015729)