摘要:
A method and apparatus for time-resolved fluorescence spectroscopy is described in which laser light from a single pulse is used to excite fluorescent photons in a sample, which fluorescence is detected by a PMT optimized for linearity and response time to produce photoelectrons which generate a current at the PMT anode. This current is discharged through an R/C network to produce a voltage amplitude waveform which is converted to an optical image, intensified, stored and digitized. The digitized version of the optical image is processed in a data processor to calculate the true fluorescence impulse response.
摘要:
An apparatus, for producing scatter-free two-dimensional X-ray images and eliminating scattering effects on integrated detector arrays, includes, in physical sequence from front to back, an X-ray source, a front two-dimensional detector positioned behind a subject for detecting both primary and scatter X-rays produced from striking the subject with the source's radiation, a collimator with holes for passing a portion of the primary X-rays, and a rear two-dimensional detector for receiving this portion. A method for producing scatter-free images which includes the steps of; X-raying the subject with high and low energy, retrieving an image pair I.sub.rHl and I.sub.rLl from the rear detector, normalizing and subtracting dark signals from I.sub.rHl and I.sub.rLl to yield an image pair D.sub.rHl and D.sub.rLl, solving D.sub.rHl and D.sub.rLl to determine b and s, retrieving an image I.sub.fh from the front detector, normalizing and subtracting dark signals from I.sub.fh to yield D.sub.fh representing the primary and scatter X-rays sum, determining D.sub.fSl of image D.sub.fh at the detector cells using b and s, interpolating D.sub.fSl for the front detector cells to yield D.sub.fSh, subtracting D.sub.fSh from D.sub.fh to yield D.sub.fPh representing the two-dimensional scatter-free image of the subject.
摘要:
An apparatus for extending the light deflection angle, so a light beam can be dynamically controlled within ±90°, pitch and yaw. The device comprises an initial dynamic beam deflector and a compound light beam direction mapper. The beam direction mapper includes a beam size reducer, a beam transmission adapter, and a projector. An initial light beam from a light source is deflected a small amount by the initial dynamic beam deflector. The initially deflected light beam is focused by the beam size reducer to a light energy spot on the beam transmission adapter, which transfers the light spot to the projector. The projector emits an output light beam at the far field of its output space with an output deflection angle larger than the initial deflection angle. All components are based on classical geometry optics and the energy of the output light beam is within an order of magnitude of that of the input light beam.
摘要:
A method for performing dual-energy x-ray imaging of a human breast including separating the breast image into five basic first order approximation image components: a dual-energy scatter image pair, a lean tissue image, a fat tissue image, and a microcalcification image. In the second order approximation, lean tissue image and fat tissue image are adjusted to correct for the microcalcification component so that each contains only a single breast component. The method also includes a calibration method so that the materials used are the actual breast tissues, instead of merely equivalent materials.
摘要:
An apparatus and method for removing scatter from x-ray images acquired by two-dimensional digital detectors. The apparatus consists of, in physical order, an x-ray source, a front two-dimensional x-ray detector, a beam selector, and a rear two-dimensional x-ray detector. The subject is located between the x-ray source and front detector. There two types of beam selectors, one allowing only primary x-rays to reach selected locations of the rear detector, and the other allowing primary x-rays and scatter to reach selected locations of the rear detector while allowing only scatter x-rays to reach shadowed locations of the rear detector. The method includes determining a low-resolution primary x-ray rear detector image, calculating an approximate low-resolution primary x-ray front detector image, calculating a high-resolution primary image at the front detector, and applying one or more of several correction procedures for achieving higher accuracy from the approximations.
摘要:
A method and apparatus for dynamically controlling variation in an attribute of a light beam employing materials with unusually high electrooptical coefficients that are subject to optical damage from the light beam being controlled. The method includes providing a transmission medium composed of a high sensitivity electrooptic material transparent to the light beam and having a nonzero electrooptic coefficient, where the medium is adapted to receive, propagate, and output the light beam. The medium is subjected to an electric field, the strength of which is controlled to determine the amount of variation of the light beam attribute. The field is generated by electrodes appropriately enclosing the medium and inducing a voltage across the electrodes. The medium is illuminated by a suppressing light source, the illumination being intense enough to significantly reduce charge distribution inhomogeneity within the medium. The intensity of the suppressing illumination is at least twice the intensity of the light beam being controlled.
摘要:
An apparatus and method for wirelessly determining position and orientation of a first object relative to a second object in six dimensions, including one or more recording assemblies and one or more identification-coded or orientation-coded optical transponders. The positions of the recording assemblies are fixed relative to the first object and the transponders are fixed relative to the second object. A light source in each recording assembly emits light into space that is received, modulated, and retransmitted back by each transponder to a photodetector assembly in the recording assembly. The identification-coded optical transponder modulates the retransmitted light with a unique fixed code. The orientation-coded optical transponder modulates the retransmitted light with a unique fixed code that depends upon the direction of the incident light. The photodetector assemblies provide one or two independent position parameters for each transponder and two independent orientation parameters for each orientation-coded transponder. The system includes a combination of recording assemblies and transponders that provides at least six independent measured parameters.
摘要:
A light beam deflector comprises an initial beam deflector that imparts a small initial deflection, and a beam deflection amplifier that increases the initial small deflection by a multiplication factor. There are five embodiments of the initial beam deflector. The first four use a pair of lenses and a piezoelectric actuator affixed to one lens. When the parallel lens axes are separated by a distance, the incident light beam will be deflected by a small angle, typically up to about 5°. The fifth embodiment comprises a mirror affixed to a piezoelectric actuator, which tilts the mirror. The beam deflection amplifier has five embodiments. The first is a Keplerian telescope lens first stage and a negative lens system second stage. The first is a Galilean telescope lens first stage and a negative lens system second stage. The third embodiment is either a Keplerian or Galilean telescope lens alone. The fourth embodiment replaces the single second lens of the first stage with a compound lens system. The fifth embodiment uses a special sphere lens alone.
摘要:
Apparatus and method for eliminating scatter effects in x-ray imaging using two-dimensional detector arrays. The apparatus consists of, in physical order, an x-ray source, a front two-dimensional x-ray detector, a beam selector, and a rear two-dimensional x-ray detector. The subject is located between the x-ray source and front detector. The beam selector prevents scatter x-rays from reaching the rear detector. The method simultaneously solves the two interdependent problems of obtaining scatter-free x-ray images and conducting dual-energy x-ray imaging with primary x-ray data. A high-resolution composite image containing primary and scatter x-ray components is read from the front detector. A low-resolution composite image is produced from the high-resolution composite image. A pair of low-resolution primary x-ray dual-energy images is read from the rear detector. Using an improved dual-energy data decomposition method, a low-resolution primary x-ray front detector image is calculated. A low-resolution scatter x-ray image is determined by subtracting the low-resolution primary x-ray front detector image from the low-resolution composite image. The low-resolution scatter x-ray image is interpolated to a high-resolution scatter x-ray image and subtracted from the high-resolution composite image to produce a high-resolution primary x-ray image.