Abstract:
An ultrafast laser providing short output pulses having a pulse length in the femtosecond range includes a resonant cavity including a plurality folding mirrors for folding the resonant cavity to shorten its overall length. The fold-mirrors each include a plurality of layers deposited by ion-beam sputtering onto a substrate having a surface roughness of less than about 0.5 nanometers RMS. One or more of the folding mirrors may have a negative-group-velocity-dispersion mirror for allowing the laser to operate in a pulsed mode with pulses having a length of less than 500 femtoseconds.
Abstract:
A polishing machine for optical elements includes: —a spindle arranged to rotationally drive an optical element; —a polishing tool mobile relative to the spindle; —a front face provided with a door enabling the access to the spindle and to the polishing tool. The polishing tool is mounted on a body which is rotationally mounted on sliding members by way of a first axis, the sliding members being substantially perpendicular to the front face.
Abstract:
A method of personal locomotion including stepping onto first and second wheeled shoe accessories and engaging the first wheeled shoe accessory against a support surface to roll on the second wheeled shoe accessory in a desired direction at an angle to a normal walking direction. The wheeled shoe accessory includes a rigid board having a length sufficient to span a width of a shoe placed sideways across the board, with the board supporting at least an arch region of the shoe. At least one axle assembly is secured to a lower surface of the board. The user experience is similar to that of a skateboard, but with decoupled feet for individual maneuverability of each wheeled shoe accessory.
Abstract:
A polishing machine for optical elements includes: —a spindle arranged to rotationally drive an optical element; —a polishing tool mobile relative to the spindle; —a front face provided with a door enabling the access to the spindle and to the polishing tool. The polishing tool is mounted on a body which is rotationally mounted on sliding members by way of a first axis, the sliding members being substantially perpendicular to the front face.
Abstract:
An interface circuit 13 is provided for a display apparatus 3 such as a television. The display apparatus 3 comprises a video signal processing circuit 8 for processing a composite video signal to derive color component signals having variable black and white levels; a linear amplifier 10 for amplifying the color component signals; and a display device 4 such as a CRT driven by the output of the linear amplifier 10. The interface circuit 13 is provided to interface the color component signals with a digital signal processor 14. The interface circuit 13 includes a modification circuit 22 arranged to perform a modification of voltage levels of the color component signals and to output the modified color component signals to the digital signal processor 14 via an A/D convertor 18. The interface circuit 13 further includes a remodification circuit 23 arranged to receive processed color component signals supplied from the digital signal processor 14 via a D/A convertor 19 and to perform a modification of the processed color component signals which is the inverse of the modification performed by the modification circuit 22. The modification and remodification circuits 22, 23 use calibration signals including the black and white levels of the color component signals inserted in a predetermined period in the vertical blanking interval of the color component signal. The interface circuit 13 reduces the resolution necessary in the A/D convertor 18.
Abstract:
An ultrafast laser providing short output pulses having a pulse length in the femtosecond range includes a resonant cavity including a plurality folding mirrors for folding the resonant cavity to shorten its overall length. The fold-mirrors each include a plurality of layers deposited by ion-beam sputtering onto a substrate having a surface roughness of less than about 0.5 nanometers RMS. One or more of the folding mirrors may have a negative-group-velocity-dispersion mirror for allowing the laser to operate in a pulsed mode with pulses having a length of less than 500 femtoseconds.
Abstract:
A fuel supply apparatus for supplying fuel to a compression ignition engine comprising a rotary distributor member having a delivery passage which can register in turn with outlet ports connected to the injection nozzles of the engine. Fuel is supplied to the delivery passage from an accumulator under the control of a valve. The accumulator is charged with fuel by means of a high pressure pump which is a cam actuated pump and fuel is supplied to the high pressure pump by a low pressure pump. A valve is provided to control the output pressure of the low pressure pump so that the amount of fuel supplied to the high pressure pump can be varied for the purpose of controlling the fuel pressure within the accumulator. This pressure is sensed by a transducer which supplies a signal to a control system which controls the flow of electric current in the valve.
Abstract:
A proximity detector for detecting the presence of a coin or token in a coin chute, comprising a pair of axially aligned coils disposed on opposed sides of the chute; a common-emitter amplifier having a base and a collector providing a detector output, one of the coils being connected to the collector and the other of the coils being connected to the base.
Abstract:
A method and system are provided for counting moving objects in a digital video stream. In contrast to known computationally-expensive methods, areas of motion are determined by threshold subtracting a current video frame from a short term average video scene. An object box surrounding an object is determined by threshold subtracting the current video frame from a long term average video scene. Coordinates of the moving object are identified by associating the area of motion with the object box, if it overlaps the area of motion, to define a moving object box. An event counter can be incremented when the moving object box is in a buffer zone in the current frame, and was in a detection zone in an earlier frame, and was initially detected in a buffer zone on the opposite side of the detection zone.
Abstract:
A monolithic sequential coupling arrangement has two or more fused biconic couplers joined with one common optical fiber which is not spliced. The couplers are close together in a space-saving relationship exhibiting a relatively low polarization dependent loss. The non-fused fiber portions in the arrangement have each at least one adiabatic taper.