EXTENDED SOURCE WAVEFRONT SENSOR THROUGH OPTICAL CORRELATION WITH A CHANGE IN CENTROID POSITION OF LIGHT CORRESPONDING TO A MAGNITUDE OF TIP/TILT ABERRATION OF OPTICAL JITTER (AS AMENDED)

An atmospheric aberration sensor that uses two optically correlated images of a scene and the Fourier transform capabilities of a lens or other focusing element. The sensor receives light via an f-number matching element from a scene or from an external optical system and transmits it through a focusing optical element to an updateable display element such as a spatial light modulator or micro mirror array, which modulates the real time image from the focusing element with previous template image of the same extended scene. The modulated image is focused onto an autocorrelation detection sensor, which detects a change in centroid position corresponding to a change of the tip/tilt in the optical path. This peak shift is detected by centroid detection and corresponds to the magnitude of global wavefront tip/tilt. With a lenslet array and detector array, the system can also measure local tip/tilt and higher order aberrations.