Patent Document ID: 5396058
Application ID: 08074900
Patent Status: 1

Claim One:
1. A method for quantitatively determining an imaging system focus error, the imaging system inputting a scene radiation field and re-imaging it at an ideal focal point, the method comprising the steps of: 1) providing a sensor having a first, second, and third radiation detector; 2) calibrating said sensor in order to generate a reference curve which accurately represents a functionality of said sensor; 3) positioning the sensor in a portion of the input scene radiation field, and orienting the sensor so that the three radiation detectors each simultaneously image the same scene radiation field, for sampling it at the three different imaging surfaces; 4) sampling the input scene radiation field at the first, second and third imaging surfaces, for recording, respectively, data corresponding to the radiation intensity of the sampled field at different points on each of the three imaging surfaces; and 5) computing an optimal imaging surface location which serves as a measure of the imaging system focus error.