Abstract: In a process and apparatus for measuring object topographies by means of projected fringe patterns, to enlarge the region of certainty, different periodicities are evaluated. Calibration of the measurement apparatus is carried out in at least two parallel planes, situated in the forward and in the rearward regions of the measurement volume. Corrected phase values are first calculated from the phase measurement values of the measurement object. By combination of the phase measurement values relating to the pattern of long periodicity and of the pattern of short periodicity, the fringe order of the phase values relating to short periodicity is calculated. By interpolation of the correction values between the two planes in which the reference measurements were carried out, the measurement process and a corresponding measurment apparatus provide highly accurate measurement values, with simultaneously reduced requirements on the accuracy of mechanical and/or optical adjustment.

Abstract: A contact applicator arrangement for applying laser radiation to an object is disclosed. The contact applicator arrangement includes: a holder having an outer surface and defining a longitudinal axis; the holder having an outlet formed in the outer surface for passing the radiation from the holder to the object; a radiation guide mounted in the holder for guiding the radiation through the outlet; and, an element displaceably mounted in the holder so as to be movable along the longitudinal axis in response to a contact pressure applied on the element. The element is movable to a first position wherein the element extends outwardly beyond the surface of the holder and to a second position rearward of the first position. These first and second positions define a displacement range of the element. A spring resiliently biases the element in opposition to the contact pressure to define a pregiven force within the displacement range of the element.

Abstract: The invention relates to measuring a phase-modulated signal 5. The signal is measured along at least five different steps (P1-P5) corresponding to preselected phase angles of the carrier wave 4. From the associated sets of measured values, at least three sets of measured values are formulated in a manner that from each of the sets a phase value [.phi..sub.i =arctan (Z.sub.i /N.sub.i) where i is equal to or greater than 3] can be calculated. The same correct phase value is computed based upon these three sets for a signal with the frequency of the carrier wave. The essence of the invention is finding that linear combinations of a.sub.i Z.sub.i and a.sub.i N.sub.i can be used for the computation of an accurate phase measurement where the factors a.sub.i are selected so that the phase error, as a function of the preselected phase steps, has at least three zero positions among the measured phase steps (P1-P5). As a result, the systemic errors that normally accompany phase measuring are significantly reduced.

Abstract: A defined determination of the field of view observed through a surgical microscope is made. To achieve this determination, the relative current position of the plane of the field of view to the position of an object detail of interest is detected in a sighting method with the aid of a position detection system operating according to the laser triangulation principle. As soon as the plane of the field of view and the object detail are coincident, then with the aid of detected optical system data, the position of the object detail with reference to the surgical microscope is determined and, with the detected coordinates of the surgical microscope, the position of the field of view is determined in space. The position detecting system required for this purpose operates on an optical basis and can be integrated into the optics of the surgical microscope.

Abstract: The invention relates to an evaluation method for interferograms and an interferometer corresponding thereto with which tile influence of coherent noise is reduced with simultaneously high interference contrast. Several phase maps are computed from interferograms which are recorded with coherent light. The interferogram components of the test object and the interferogram components of the coherent noise are displaced relative to each other in the camera plane between recording the interferograms. The influence of the coherent noise is suppressed by subsequently averaging the phase maps.

Abstract: A method for target-range measurement of round-trip transit time, for laser light pulses transmitted from the rangefinder and target-reflected back to a measuring device, is based on the fact that a predetermined measurement cycle is subdivided into time intervals and that, in each time interval, it is recorded whether a reflected light pulse has or has not arrived. A system for carrying out the method is characterized by the fact that, instead of totalizing counter modules, successive storage locations in a serial memory device are sequentially indexed under clock-pulse control and, depending upon the time at which a target-reflected pulse is detected, a logic signal is supplied for storage at the instantaneously receptive location within the memory device. Signal-evaluation apparatus including a microprocessor is connected to the memory device to evaluate range from the memory location at which the logic signal is found.

Abstract: The invention is directed to a mechanical control unit for a supporting stand for a surgical microscope. The mechanical control unit constrains the surgical microscope to move along the surface of a sphere about the point at which surgery is performed when spatially moving the microscope. In this way, the focusing adjustment of the surgical microscope onto the point of surgery is maintained for each viewing direction. The mechanical control unit is connected via adaptation positions to the supporting stand which is translationally movable in three spatial directions and is rotationally movable about three axes.

Abstract: An instrument is mounted on a motorized positioning mechanism for providing a contactless guidance of the instrument. A transmitting unit and a receiving unit are arranged in a defined relative position to an operator and the instrument so that an evaluation unit positions the instrument via corresponding control signals with the aid of the registered signals of the receiving unit. A preferred application is the contactless guidance of a surgical microscope which tracks the head movements of the surgeon.

Abstract: The present invention relates to a method for evaluating fringe images, in particular, for topographic measurements. During a first step, several phase-displaced patterns are recorded sequentially in time, and the respective phase relations of these patterns are determined by evaluation in the spatial domain (14a, 14b, 15). During a second step, after the phase shifts have been determined accurately in this manner based on the video images themselves, a pixel-by-pixel evaluation of the phase-displaced pattern is performed in the time domain. The invention also includes computer hardware for performing the evaluation of the strip images in video real time.

Abstract: The invention is directed to an arrangement for shaping a laser beam and for reducing the coherence thereof. The arrangement has at least two approximately parallel mirrors arranged approximately perpendicular to the laser beam. One of the mirrors is fully reflective whereas the other mirror is partially reflective so that the exiting light beam comprises several mutually adjacent or partially overlapping component beams which are reflected a different number of times. The spacing of the mirrors is greater than half the coherence length of the laser. An advantageous embodiment provides the arrangement on a plane-parallel glass plate with the degree of reflection of the partially-reflective mirror being reduced in a stepwise manner and with a partial overlapping of the exiting component beams.

Abstract: For defined positioning of a laser beam in an ophthalmological instrument with a slit projection device and an optical observation unit, a focusing objective is displaced by a displacement device in a plane parallel to the observation beam path of the optical observation unit. The laser beam path and the slit projection beam path are separately deflected coaxially with the observation beam path in the direction of the target plane. Defined positioning of a laser beam in the patient's eye is achieved by means of the displacement device, which includes a displacement element connected to the focusing objective, and an operating element. The displacement device furthermore offers diverse means of adjustment.

Abstract: A computer-operated coordinate-measurement machine has two length-measurement systems arranged in parallel for measuring the longitudinal displacement of a probe carried by the portal (3-5) of the machine, and these two length-measurement systems (13, 14) may belong to different precision classes. A computer-associated device (16) forms an absolute position-measurement value (Ym) from length-measurement signals of the more precise measurement system (13) and said device forms a dynamic measurement or instantaneous deviation value (Ys-Ym) from the difference between length-measurement signals of the respective systems (13, 14). The computer of the machine calculates the effective instantaneous position (Ym+.DELTA.y) of the probe (9a, b, c) borne by the portal (3-5), using the instantaneous value of the transverse position of the probe on the portal, in conjunction with the absolute measurement value (Ym) and the dynamic measurement value (Ys-Ym).

Abstract: A motorized stand for positioning medical therapeutic or diagnostic instruments is mechanically coarsely balanced by weights. A defined positioning of the medical instrument is determined by means of several drive units with integrated angle transducers. Operating safety is additionally ensured, in the event of failure of a drive unit, by the use of two angle transducers per drive unit. One angle transducer is coupled to the drive motor of each drive unit. The other angle transducer is independent of the drive motor.

Abstract: A vision testing system includes polarization spectacles having different polarization axes with or without .lambda./4 filters for the two polarization lenses forward of the eye of the patient to be tested. This system also includes a vision testing apparatus for generating light having a specific polarization direction. The vision testing apparatus includes essentially two polarization filters and two LCD-displays which are mounted alternately one behind the other. This arrangement can so influence the light coming from the light source that test figures or portions of the test figures can be seen by one eye or by both eyes. If a test figure is to be changed, then a corresponding command is issued via a key pad to a switching unit which drives two drive circuits of the two LCD-displays in a desired manner. By making appropriate modifications of the vision testing apparatus, a patient can be tested as to color-vision acuity.

Abstract: In a slit lamp microscope, changeover can be selectively made between conventional slit lamp microscopy and confocal perforated disk microscopy. In slit lamp operation, the microscope is constructed as a stereo microscope. The Nipkow perforated disk required for the confocal perforated disk microscopy is arranged in an indirect beam path. Alternatively, the Nipkow disk can be arranged on a pivotable support element and can be pivoted into the beam path in the vicinity of an intermediate image plane. For confocal perforated disk microscopy, an additional illumination device is provided that is reflected into the beam path between the Nipkow disk and the oculars. The insertion of the Nipkow disk or the switching of the beam paths takes place such that the focal plane of the objective is constant. A changeover is made from conventional slit lamp microscopy to confocal perforated disk microscopy without refocusing. A direct comparison of the images observed with the two procedures is therefore possible.

Abstract: An ophthalmoscopic attachment 1 for a surgical microscope 13 accommodates an optical system 14 which erects an inter-image of the fundus (or other particular area of the vitreous body of the eye) produced by at least one ophthalmoscopic lens 8 and interchanges the optical viewing paths. The optical system 14 is located directly behind the produced inter-image at a point where the stereoscopic optical viewing paths are still intertwined. The optical system 14 is configured either as a triplet with field lenses or as a straight-view inversion prism. The attachment also includes a lens 15 that is (a) positioned between the optical system 14 and the lens end of the attachment, and (b) movable along the optical axis of the attachment to put the critical section of the eye into focus.

Abstract: The invention relates to an imaging system for charged particles having a correction unit for correcting an objective lens. The correction unit essentially includes a beam deflector and a mirror which reflects the incoming particle beam. A first symmetry plane of the deflector is imaged in the mirror. The mirror images this first symmetry plane at an imaging scale of 1:1 in a second symmetry plane of the deflector. At the same time, the symmetry planes are either intermediate image planes or diffraction planes. With the high symmetry of the imaging system, the condition is achieved that the aberrations of the second order caused by a one-time passthrough through the deflector are cancelled after the second passthrough. The mirror can be so adjusted that its negative chromatic aberration compensates for the chromatic aberration of the objective lens and the other lenses. The spherical aberration can be compensated independently thereof with the aid of a hexapole which is centered in a diffraction plane.

Abstract: Described are a method and apparatus for the optical testing of samples in which a camera records a plurality of images of an interferogram or a bar pattern. Phase values are determined for each image point of each camera record, and then differences between the phase values of adjacent points in each image line and column are computed in modulo 2.pi.. These differences for each image point are summed over the plurality of camera images. After a number of images sufficient to assure desired accuracy have been summed, a single discontinuity elimination is carried out. This permits the rapid averaging of measurements over the plurality of camera images in real video time and remarkably reduces the measuring time and statistical errors.

Abstract: The invention is directed to a pancratic mirror objective system for laser focussing and especially for laser machining apparatus. The pancratic mirror objective system preferably includes a convex paraboloid mirror and an ellipsoid mirror. The ellipsoid mirror can be approximated by a toric or spherical form. The focus F.sub.1 of the paraboloid mirror P and the first focus of the ellipsoid mirror E are coincident. By rotating the ellipsoid mirror E about the axis parallel to the incident laser beam through the first focus F.sub.1, the effective image side aperture (for example K=4 to K=8) and the focal length are varied. The track control compensates for the movement of the focus F.sub.2 in laser machining apparatus.

Abstract: A single projector is used to project a grating pattern on the surface of the object being measured, and the grating pattern is recorded simultaneously by two cameras from two different directions relative to the direction of projection. Both cameras record images of the same object areas. The fringe phases of the image patterns recorded by each of the two cameras are computed separately; and the object coordinates, which are computed from the combination of the computed fringe phases of both cameras, are unambiguous within a large measured range.