Abstract: System and method are described for synchronizing a pulsed source of the near infrared illumination used in visualizing subcutaneous structures with the background illumination normally extant in medical treatment settings that allow both enhanced image acquisition and use of higher power pulsed infrared illumination sources.

Abstract: System and method are described for synchronizing a pulsed source of the near infrared illumination used in visualizing subcutaneous structures with the background illumination normally extant in medical treatment settings that allow both enhanced image acquisition and use of higher power pulsed infrared illumination sources.

Abstract: A low-photon flux image-intensified electronic camera comprises a gallium arsenide phosphide (GaAsP) photocathode in a high vacuum tube assembly behind a hermetic front seal to receive image photons. Such is cooled by a Peltier device to ?20° C. to 0° C., and followed by a dual microchannel plate. The microchannels in each plate are oppositely longitudinally tilted away from the concentric to restrict positive ions that would otherwise contribute to the generation high brightness “scintillation” noise events at the output of the image. A phosphor-coated output fiberoptic conducts intensified light to an image sensor device. This too is chilled and produces a camera signal output. A high voltage power supply connected to the dual microchannel plate provides for gain control and photocathode gating and shuttering. A fiberoptic taper is used at the output of the image intensifier vacuum tube as a minifier between the internal output fiberoptic and the image sensor.

Abstract: A high-speed optical switch having a first light port, a second light port, a focussing system, a mirror, and a motor. The focussing system focuses light from the first light port at a focal point via a first optical path, and focuses light from the second light port at a point at or near the focal point via a second optical path. The first optical path is angularly separated from the second optical path. The mirror is located at or near the focal point. The motor is coupled to the mirror and sequentially rotates the mirror back-and-forth between a first rotational position, at which the mirror reflects light from first light port into the second light port via the first optical path and the second optical path, and a second rotational position, at which the mirror reflects the light from the first light port to a location outside the second light port.

Abstract: A high-speed optical switch having a first light port, a second light port, a focussing system, a mirror, and a motor. The focussing system focuses light from the first light port at a focal point via a first optical path, and focuses light from the second light port at a point at or near the focal point via a second optical path. The first optical path is angularly separated from the second optical path. The mirror is located at or near the focal point. The motor is coupled to the mirror and sequentially rotates the mirror back-and-forth between a first rotational position, at which the mirror reflects light from first light port into the second light port via the first optical path and the second optical path, and a second rotational position, at which the mirror reflects the light from the first light port to a location outside the second light port.

Abstract: A method for deriving an output signal from an input video signal generated by an image sensor having an image formed on a part of it. The input video signal includes an image portion generated by the part of the image sensor on which the image is formed, and an external portion generated by the part of the image sensor on which the image is not formed. In the method according to the invention, the input video signal is received, the external portion of the input video signal is identified, and the output signal is generated from the input signal by replacing the external portion with a synthesized portion. The synthesized portion may set the external area to black level, to a predetermined luminance and/or hue, or to a luminance and/or hue adaptively determined in response to the image portion of the input signal. A position-dependent variation may also be imposed on the external area. The external area may also be rearranged to change the displayed location of the image.

Abstract: A high-speed optical switch having a first light port, a second light port, a focussing system, a mirror, and a motor. The focussing system focuses light from the first light port at a focal point via a first optical path, and focuses light from the second light port at a point at or near the focal point via a second optical path. The first optical path is angularly separated from the second optical path. The mirror is located at or near the focal point. The motor is coupled to the mirror and sequentially rotates the mirror back-and-forth between a first rotational position, at which the mirror reflects light from first light port into the second light port via the first optical path and the second optical path, and a second rotational position, at which the mirror reflects the light from the first light port to a location outside the second light port.

Abstract: Apparatus for coupling a light beam from a light source to a light fibre with reduced heating of the light fibre. The light source has a lamp, a condenser lens, and a dichroic infra-red filter disposed along an optical axis between the lamp and the light fibre. The apparatus is adapted for operation with plastic light fibres that have a softening temperature of less than 100 degrees Celsius. The apparatus comprises light fibre connector that secures the light fibre on the optical axis. A non-visible radiation filter is located on the optical axis in a broad part of the light beam between the dichroic filter and the light fibre and reduces non-visible radiation energy remaining in the light beam following the dichroic filter. A beam restrictor is located on the optical axis adjacent to, and thermally isolated from, the light fibre connector.

Abstract: An output video signal is derived from an input video signal generated by an image sensor in response to an image formed on only part of the image sensor. The output video signal is derived in response to only the portion of the input video signal generated by the part of the image sensor on which the image is formed. The input video signal additionally includes a portion generated by the part of the image sensor on which the image is not formed. An image signal generating apparatus is provided in which the image sensor is mounted, and which includes a detachably-attached image-forming device. When attached to the image signal generating apparatus, the image-forming device forms the image on the part of the image sensor. A frame of the input video signal is received from the image sensor.

Abstract: A method of attaching a Gradient Index (GRIN) lens to an optical fibre in the course of making an optical instrument for use at a working distance. The method is especially suitable for making an optical instrument with an extended working distance. In the method, a test object, a GRIN lens, and an optical fibre are provided. The GRIN lens is placed at the working distance from the test object, and is axially aligned with the test object. The optical fibre is placed adjacent to, and axially aligned with, the GRIN lens to form an image of the test object at the proximal face of the optical fibre. The distal face of the optical fibre is placed adjacent to the proximal face of the GRIN lens. At least one of the GRIN lens and the optical fibre is moved axially with respect to the other until the image of the test object is in focus. This determines an optimum axial spacing between the GRIN lens and the optical fibre.

Abstract: A dynamically variable electronic delay line for real time ultrasonic imaging systems is disclosed which controllably phases the signals associated with an array of electromechanical transducer elements and thereby enables selective scanning and dynamic focusing of a target. A controllable variable electronic time delay apparatus is coupled to each of the electromechanical transducer elements of the array having separate write-in and read-out addressing capabilities. The signals associated with a respective ultrasonic transducer element are fed in at selected write-in addresses and subsequently read-out and extracted after an initial time delay interval. The write-in and read-out address pointers of the memory system are continuously sequenced during operation of the device and the time delay interval is a function of the difference between the addresses and the clock rate.

Abstract: A dynamically variable electronic delay line for real time ultrasonic imaging systems is disclosed which controllably phases the signals associated with an array of electromechanical transducer elements and thereby enables selective scanning and dynamic focusing of a target. A controllable variable electronic time delay apparatus is coupled to each of the electromechanical transducer elements of the array having separate write-in and read-out addressing capabilities. The signals associated with a respective ultrasonic transducer element are fed in at selected write-in addresses and subsequently read-out and extracted after an initial time delay interval. The write-in and read-out address pointers of the memory system are continuously sequenced during operation of the device and the time delay interval is a function of the difference between the addresses and the clock rate.

Abstract: A dynamically variable electronic delay line for real time ultrasonic imaging systems is disclosed so as to controllably phase the signals associated with an array of electro-mechanical transducer elements and thereby enable the selective scanning and dynamic focusing of a target. A controllable variable electronic time delay apparatus is coupled to each of the electromechanical transducer elements of the array and in one embodiment thereof constitutes an electronic memory having separate write-in and read-out addressing capabilities. The signals associated with a respective ultrasonic transducer element are fed in at selected write-in addresses and subsequently read-out and extracted after an initial time delay interval. The write-in and read-out address pointers of the memory are continuously sequenced during operation of the device and the time delay interval is a function of the difference between the addresses, as well as the clock rate.

Abstract: A positron imaging system and method in which two opposed Anger cameras are employed on opposite sides of an organ to be imaged. The cameras include a planar unitary scintillation crystal approximately one inch in thickness, and the electronics which process the signals from the cameras include pulse shaping circuitry to reduce both the duration and the integration time of pulses resulting from radioactive events. Both cameras exclude collimators to enable radiation incident upon them at many angles to be accepted, and means are included to rotate the opposed cameras about the organ of interest to enable transverse tomographic imaging.