Abstract: A schlieren imaging system provides quantitative images suitable for testing medical equipment. One embodiment includes precision optics which form an image of a volume of a medium through which an ultrasonic acoustic wave propagates. A spatial filter passes diffracted light but blocks other light. A camera forms an image of the medium from the diffracted light so that regions of the medium which diffract light have higher light intensity in the image. From image intensities, a processor determines acoustic pressures or intensities, typically as a value indicating an integral of the acoustic pressure or intensity along an optical path through the volume. Integrated pressure is determined from a look-up table which relates predicted light intensity to pressure values which cause the predicted light intensity. The system is calibrated by forming an image of a reference ultrasonic acoustic wave and determining a relation between the image intensities and predicted intensities.

Abstract: The invention provides an achromatic expansion prism for use in magneto-optical disk drive systems. The achromatic expansion prism comprises a first prism having a first dispersion value, an entrance surface through which a light beam enters the first prism and an outlet surface through which the light beam exits the first prism, and a constant deviation prism fixed to the outlet surface of the first prism and having a second dispersion value. The constant deviation prism reflects the light beam in a first direction to the optical disk and reflects the light beam reflected from the optical disk in a second direction to a detector. The angle between the first and the second directions is constant irrespective of the angle of incidence of the light beam on the first prism. Moreover, the first and second dispersion values are selected such that the first and second directions are independent of wavelength of the light beam.

Abstract: Focus and tracking error optical servo detector apparatus is shown employing a single four element detector array. Focus error detection based on spot size sensing is described in which focus error offset caused by beam transition between track and non-track areas is substantially reduced by shaping the detector element areas so as to derive servo signals from substantially only the overlap lobes between the zeroth order diffraction beam and the plus and minus first order diffraction beams in the optical readout beam from the recording element. The readout beam incident on the detector is anamorphically shaped to retain high focus error signal gain while reducing sensitivity in the tracking direction to movement of the beam caused by factors such as thermally induced beam misalignment, vibration and the like.

Abstract: A method and apparatus for anamorphically shaping a beam of radiation and for deflecting such beam by 90.degree. independently of beam wavelength shifts within a predetermined wavelength range. The apparatus of the invention comprises an achromatic prism comprising a pair of prism elements of different optical materials. The prism elements are joined together to define a complex prism having four faces which interact with an incident beam to achieve a desired beam shaping and deflection. Two of such faces are parallel, one face being in a plane parallel to the direction of propagation of an incident beam, and the other being in a plane perpendicular to the beam exiting the prism.

Abstract: In a CRT display of digitized gray scale information from a diagnostic scan, an operator-selectable area of the display can be highlighted to increase the contrast and brightness of a selected portion of the image while simultaneously viewing a wide range of information levels in the background portion of the image. The highlighted area and the background may encompass different operator-selectable information level windows. To accommodate the wide dynamic range necessary for such a display, and eliminate possible contouring effects when enhancing dark areas of the image, more gray scale display levels are used than are commonly used with diagnostic scanning systems, and full black on the CRT is set to correspond to a minimum digital display level sufficiently high so that no single display step results in more than a maximum predetermined contrast ratio in the display.

Abstract: A scintillation probe employing two scintillation detectors having partially overlapping fields of view. The overlapping fields of view allow radioactive events from a particular spatial region to be identified and tabulated separately. Preferably, one crystal is annularly positioned with respect to the other and is collimated so that radioactive events from the left ventricle of the human heart can be isolated to a large extent from simultaneous background. Useful cardiac information is obtained in a non-invasive technique of medical examination of living patients requiring only a single injection of a radioisotope.

Abstract: Method and apparatus for analyzing blood or other biological fluids containing cells or particles of interest by passing them sequentially through a narrow flow chamber where a repetitive physical stimulus, such as a plurality of beams of light, is spaced at intervals to form a code along the length of the flow chamber to elicit responses from the particles. These responses are then decoded and used to classify the particles according to type.