Abstract: An obstacle detector for a mobile robot while the robot is in motion is disclosed. The detector preferably includes at least one light source configured to project pulsed light in the path of the robot; a visual sensor for capturing a plurality of images of light reflected from the path of the robot; a processing unit configured to extract the reflections from the images; and an obstacle detection unit configured to detect an obstacle in the path of the robot based on the extracted reflections. In the preferred embodiment, the reflections of the projected light are extracted by subtracting pairs of images in which each pair includes a first image captured with the at least one light source on and a second image captured with the at least one light source off, and then combining images of two or more extracted reflections to suppress the background.

Abstract: An obstacle detector for a mobile robot while the robot is in motion is disclosed. The detector preferably includes at least one light source configured to project pulsed light in the path of the robot; a visual sensor for capturing a plurality of images of light reflected from the path of the robot; a processing unit configured to extract the reflections from the images; and an obstacle detection unit configured to detect an obstacle in the path of the robot based on the extracted reflections. In the preferred embodiment, the reflections of the projected light are extracted by subtracting pairs of images in which each pair includes a first image captured with the at least one light source on and a second image captured with the at least one light source off, and then combining images of two or more extracted reflections to suppress the background.

Abstract: An obstacle detector for a mobile robot while the robot is in motion is disclosed. The detector preferably includes at least one light source configured to project pulsed light in the path of the robot; a visual sensor for capturing a plurality of images of light reflected from the path of the robot; a processing unit configured to extract the reflections from the images; and an obstacle detection unit configured to detect an obstacle in the path of the robot based on the extracted reflections. In the preferred embodiment, the reflections of the projected light are extracted by subtracting pairs of images in which each pair includes a first image captured with the at least one light source on and a second image captured with the at least one light source off, and then combining images of two or more extracted reflections to suppress the background.

Abstract: An obstacle detector for a mobile robot while the robot is in motion is disclosed. The detector preferably includes at least one light source configured to project pulsed light in the path of the robot; a visual sensor for capturing a plurality of images of light reflected from the path of the robot; a processing unit configured to extract the reflections from the images; and an obstacle detection unit configured to detect an obstacle in the path of the robot based on the extracted reflections. In the preferred embodiment, the reflections of the projected light are extracted by subtracting pairs of images in which each pair includes a first image captured with the at least one light source on and a second image captured with the at least one light source off, and then combining images of two or more extracted reflections to suppress the background.

Abstract: A imaging assembly for generating a light beam suitable for sintering comprises a lamp housing and a lamp mounted in the lamp housing comprising a filament and a lamp base, wherein the lamp is oriented with the lamp base to the side of the filament. The imaging assembly further comprises a reflector, an aperture, and at least one condenser lens configured to focus light emitted by the filament through the aperture. The imaging assembly further comprises a set of achromatic doublet lenses, each achromatic doublet lens comprising three surfaces optimized to focus light at three wavelengths, wherein the set of achromatic doublet lenses focuses light over a range including the three wavelengths. The imaging assembly further comprises an outer lens, wherein the focused light beam exits the imaging assembly through the outer lens.

Abstract: A system (100) for directing incident sun light to a receiver (150) based on an integral imager (116) is disclosed. The system includes an imager (116) mounted to a reflector (112); a tracking controller (226) coupled to the imager; and one or more actuators (114) connected to the reflector and tracking controller. The tracking controller (226) is configured to receive and process image data from the imager (116); determine angular positions of a radiation source and target relative to the mirror normal vector (N) based on the image data; and orient the reflector with the axis bisecting the angular positions of the sun and receiver (150). When the optical axis of the imager is precisely aligned with the vector normal to the reflector, the source and target will be detected as antipodal spots (320, 330) with respect to the center of the imager's field of view, which may be used to effectively track the sun or like object.

Abstract: The invention in the preferred embodiment features a solar concentrator that can align and/or track based on images from a video camera, for example. The concentrator preferably includes one or more optical elements for directing light to a receiver, a camera for capturing an image of the optical elements, and a controller configured to: detect the orientation of the one or more optical elements from the one or more images, determine an orientation error based on the detected orientation, and automatically orient the one or more optical elements to minimize the orientation error. The optical elements generally comprise a plurality of mirrors or lenses arranged in a one or two dimensional array.

Abstract: A system (100) for directing incident sun light to a receiver (150) based on an integral imager (116) is disclosed. The system includes an imager (116) mounted to a reflector (112); a tracking controller (226) coupled to the imager; and one or more actuators (114) connected to the reflector and tracking controller. The tracking controller (226) is configured to receive and process image data from the imager (116); determine angular positions of a radiation source and target relative to the mirror normal vector (N) based on the image data; and orient the reflector with the axis bisecting the angular positions of the sun and receiver (150). When the optical axis of the imager is precisely aligned with the vector normal to the reflector, the source and target will be detected as antipodal spots (320, 330) with respect to the center of the imager's field of view, which may be used to effectively track the sun or like object.

Abstract: A imaging assembly for generating a light beam suitable for sintering comprises a lamp housing and a lamp mounted in the lamp housing comprising a filament and a lamp base, wherein the lamp is oriented with the lamp base to the side of the filament. The imaging assembly further comprises a reflector, an aperture, and at least one condenser lens configured to focus light emitted by the filament through the aperture. The imaging assembly further comprises a set of achromatic doublet lenses, each achromatic doublet lens comprising three surfaces optimized to focus light at three wavelengths, wherein the set of achromatic doublet lenses focuses light over a range including the three wavelengths. The imaging assembly further comprises an outer lens, wherein the focused light beam exits the imaging assembly through the outer lens.

Abstract: A system (100) for directing incident sun light to a receiver (150) based on an integral imager (116) is disclosed. The system includes an imager (116) mounted to a reflector (112); a tracking controller (226) coupled to the imager; and one or more actuators (114) connected to the reflector and tracking controller. The tracking controller (226) is configured to receive and process image data from the imager (116); determine angular positions of a radiation source and target relative to the mirror normal vector (N) based on the image data; and orient the reflector with the axis bisecting the angular positions of the sun and receiver (150). When the optical axis of the imager is precisely aligned with the vector normal to the reflector, the source and target will be detected as antipodal spots (320, 330) with respect to the center of the imager's field of view, which may be used to effectively track the sun or like object.

Abstract: A non-penetrating, roof-mounted, solar energy concentrator is disclosed. The invention in the preferred embodiment includes a receiver adapted to convert light into electricity; one or more reflectors adapted to direct solar light to the receiver; and a frame affixed to the receiver and one or more reflectors. The frame includes a plurality of footings adapted to frictional affix the frame to a roof, such that the concentrator is detachably secured to the roof with compromising the integrity of the roof. The footings may include or receive ballast used to increase the weight of the concentrator, thereby increasing the friction used to affix the concentrator to the roof without fasteners that penetrate the roof. The footings in some embodiments are also configured to deflect the wind, thereby reducing the wind load on the concentrator.

Abstract: Disclosed is an electrowetting-based apparatus comprising, in some embodiments, a plurality of immiscible fluids. The boundary between the fluids is made substantially planar with the application of select voltages to electrodes distributed around the cell containing the fluids. The electrodes are also adapted to alter the orientation of the substantially-planar fluid boundary, thereby allowing the fluid boundary to be steered in a determined direction. Light impinging on the boundary may therefore be refracted and redirected in a determined direction. Similarly, a reflective surface may be held in suspension at the fluid boundary, thereby providing a mirror with which to redirect impinging light. The electrowetting cell disclosed herein may be used as an optical switch, actuator, lens, concentrator, or like device.

Abstract: A system (100) for directing incident sun light to a receiver (150) based on an integral imager (116) is disclosed. The system includes an imager (116) mounted to a reflector (112); a tracking controller (226) coupled to the imager; and one or more actuators (114) connected to the reflector and tracking controller. The tracking controller (226) is configured to receive and process image data from the imager (116); determine angular positions of a radiation source and target relative to the mirror normal vector (N) based on the image data; and orient the reflector with the axis bisecting the angular positions of the sun and receiver (150). When the optical axis of the imager is precisely aligned with the vector normal to the reflector, the source and target will be detected as antipodal spots (320, 330) with respect to the center of the imager's field of view, which may be used to effectively track the sun or like object.

Abstract: A three-dimensional printer adapted to construct three dimensional objects is disclosed. In an exemplary embodiment, the printer includes a first surface adapted to receive a bulk layer of sinterable powder, a polymer such as nylon powder; a radiant energy source, e.g., an incoherent heat source adapted to focus the heat energy to sinter an image from the layer of sinterable powder; and a transfer mechanism adapted to transfer or print the sintered image from the first surface to the object being assembled while fusing the sintered image to the object being assembled. The transfer mechanism is preferably adapted to simultaneously deposit and fuse the sintered image to the object being assembled. The process of generating an image and transferring it to the object being assembled is repeated for each cross section until the assembled object is completed.

Abstract: The present invention provides a method and apparatus for accelerated handwritten symbol recognition in a pen based tablet computer. In one embodiment, handwritten symbols are translated into machine readable characters using special purpose hardware. In one embodiment, the special purpose hardware is a recognition processing unit (RPU) which performs feature extraction and recognition. A user inputs the handwritten symbols and software recognition engine preprocesses the input to a reduced form. The data from the preprocessor is sent to the RPU which performs feature extraction and recognition. In one embodiment, the RPU has memory and the RPU operates on data in its memory. In one embodiment, the RPU uses a hidden Markov model (HMM) as a finite state machine that assigns probabilities to a symbol state based on the preprocessed data from the handwritten symbol. In another embodiment, the RPU recognizes collections of symbols, termed “wordlets,” in addition to individual symbols.

Abstract: An accurate and cost effective heliostat array and method of use is disclosed. The heliostat array in the preferred embodiment comprises a plurality of mirrors arrayed in a common plane, a plurality of reflector positioning arms, and a rigid positioning plate. The positioning plate, which is coupled to each of the reflectors via a positioning arm, is adapted to simultaneously aim each reflector using as few as one or two actuators. When the positioning arms forms the base of an isosceles triangle with one leg aligned with a ray directed to the sun and the other equal length leg aligned with a ray directed to the receiver, the positioning plate has the shape of a Conchoid of Nicomedes surface of revolution, which enables the heliostat array to simultaneously orient all of the mirrors to precisely focus incident sunlight from anywhere in the celestial hemisphere onto a common focal point.

Abstract: A non-penetrating, roof-mounted, solar energy concentrator is disclosed. The invention in the preferred embodiment includes a receiver adapted to convert light into electricity; one or more reflectors adapted to direct solar light to the receiver; and a frame affixed to the receiver and one or more reflectors. The frame includes a plurality of footings adapted to frictional affix the frame to a roof, such that the concentrator is detachably secured to the roof with compromising the integrity of the roof. The footings may include or receive ballast used to increase the weight of the concentrator, thereby increasing the friction used to affix the concentrator to the roof without fasteners that penetrate the roof. The footings in some embodiments are also configured to deflect the wind, thereby reducing the wind load on the concentrator.

Abstract: A three-dimensional printer adapted to construct three dimensional objects is disclosed. In an exemplary embodiment, the printer includes a first surface adapted to receive a bulk layer of sinterable powder, a polymer such as nylon powder; a radiant energy source, e.g., an incoherent heat source adapted to focus the heat energy to sinter an image from the layer of sinterable powder; and a transfer mechanism adapted to transfer or print the sintered image from the first surface to the object being assembled while fusing the sintered image to the object being assembled. The transfer mechanism is preferably adapted to simultaneously deposit and fuse the sintered image to the object being assembled. The process of generating an image and transferring it to the object being assembled is repeated for each cross section until the assembled object is completed.

Abstract: The present invention provides a method and apparatus for accelerated handwritten symbol recognition in a pen based tablet computer. In one embodiment, handwritten symbols are translated into machine readable characters using special purpose hardware. In one embodiment, the special purpose hardware is a recognition processing unit (RPU) which performs feature extraction and recognition. A user inputs the handwritten symbols and software recognition engine preprocesses the input to a reduced form. The data from the preprocessor is sent to the RPU which performs feature extraction and recognition. In one embodiment, the RPU has memory and the RPU operates on data in its memory. In one embodiment, the RPU uses a hidden Markov model (HMM) as a finite state machine that assigns probabilities to a symbol state based on the preprocessed data from the handwritten symbol. In another embodiment, the RPU recognizes collections of symbols, termed “wordlets,” in addition to individual symbols.