Abstract: This invention is directed to a new and improved system for determining optical aberrations, such as for example alignment, focus, tilt, astigmatism or coma of a telescope optical system, wherein the telescope optical system is arranged for imaging a random scene and includes a plurality of subapertures, said system comprising a grating disposed at the focal plane of the telescope optical system, an apodizing mask disposed adjacent the grating, said mask having transparent and opaque portions, an array of light detectors, a field lens disposed adjacent the grating for causing the subapertures to be imaged on the array of detectors, apparatus for effecting relative movement between the grating and the other elements, phase detector electronics for receiving the output from the detectors and outputting individual detector signals, and a processor responsive to the detector signals for determining the difference in phase between the individual detector signals and a reference phase, whereby a measure of the aber

Abstract: A sample cell is described that permits the measurement of the light scattering properties of very small liquid-borne samples with negligible background interference form the illumination source. A technique is described whereby the cell construction permits the measurement of the illumination intensity at the scattering sample itself, permitting, thereby, the normalization of each detected scattered signal. The cell structure and detection method incorporated therein also permit measurement of extremely small angle scattered intensities without interference of the incident light beam itself.

Abstract: An image of a moving object with an optically differentiatable structure is projected onto a grid of opto-electric transducers through a lens. The output signals of at least one square group of four transducers A-D are processed to produce from output signals of the respective transducers a pair of signals I=A+B-C-D and II=B+C-A-D. The nature of the object is such as to cause periodically varying signals in the transducers, and there are thus concerned two signals shifted by a quarter period, from which the direction of movement can be determined by means of a logic circuit. From the frequency of the signals the velocity can be ascertained. By means of direction dependent counters the path of the object can be determined from the signals. With a two dimensional matrix of transducers measurements can be effected of movement of the object in different directions. The measurement is simple and offers versatile possibilities of exploitation.

Abstract: A method and apparatus for determining the true edge length of a body subtended by two other body edges comprises exposing the body to a beam of light such that the edge is imaged by an optical system for projecting a linear section across the body as a silhouette-like image onto a linear array of photosensitive detectors. The image is usually blurred due to diffraction effects. The body is initially positioned in focus and then scanned moving the array provide an image of at least a portion of the desired edge to define a reference line representing the location of the edge. The array is then moved in scanned sequence from that reference line to provide fifty percent (50%) intensity level data points to define the other body edges. Lines are fitted through such data points and extended to intersect the reference line to determine the true length of the edge even with a blurred image of portions of that edge.