Method for estimating focusing state of on-board telescope, in observation satellite, involves measuring difference between homologous pixels of images, where difference represents focusing state of optical instrument

摘要

The method involves comparing two images of a scene acquired by a sensor assembly and area inter barrettes. Difference (dx) between homologous pixels of the images is measured, where the difference represents focusing state of an optical instrument. Comparison of the images is implemented by a correlation matrix, where the measured difference corresponds to an averaging column of the correlation matrix. Relationship between the variation with optimal focusing and the difference induced by defocusing is expressed according to an odd function. An independent claim is also included for a computer program comprising a set of instructions to perform a method for estimating focusing state of an optical instrument.