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154 results about "Active illumination" patented technology

Fast calibration method of active projection three dimensional measuring system based on two-dimension multi-color target

The invention discloses a projector and camera simultaneous fast calibration method used for an active projection illumination three dimensional appearance measuring system. The method utilizes a reasonable color design and utilizes the projector for projecting an image with multi-color characteristic points onto a two-dimension planar target with multi-color characteristic points on the basis of the RGB model of a multi-color image; a multi-color camera obtains two images after color blending in a color space of multi-color patterns on the target simultaneously at one time; information of a characteristic point image made on the target and information of a characteristic point image of projection are obtained by image separation; and then the method respectively utilizes the separated characteristic point image made on the target to calibrate the camera, utilizes the separated characteristic point image of projection to calibrate the projector and finally utilizes the principle of binocular stereovision to calibrate the relative position relationship of the camera and the projector, thus completing the calibration of the whole active illumination three dimensional appearance measuring system. As just one image is needed to be shot at each calibration position, the method has the advantages of less measuring data and fast calibration speed.
Owner:SICHUAN UNIV

Preparation method of nano-structure oil-water separation net membrane with self-cleaning and underwater super-oleophobic characteristics

The invention discloses a preparation method of a metal net membrane with self-cleaning and underwater super-oleophobic characteristics. The metal net membrane can achieve efficient oil-water separation and self cleaning. A traditional oil-water separation membrane has the defects that a preparation technology is complex, regeneration is difficult, and repeated using can not be achieved. With a copper net being a substrate, an anodic oxidation method is adopted for generating a copper hydroxide nanowire array, multiple layers of titanium dioxide are deposited on the nanowire array through layer-by-layer self-assembly, and the copper net membrane covered by a copper oxide/titanium dioxide composite membrane layer is generated through roasting. The net membrane is high in mechanical performance and resistant to high heat, has the super-hydrophilic and underwater super-oleophobic characteristics, can efficiently separate an oil-water mixture and meanwhile can perform self cleaning under photocatalysis active illumination of the titanium dioxide layer to achieve regeneration and repeated using. Compared with the preparation technology of the existing oil-water separation membrane, the method facilitates scale expansion, preparation is easy, raw materials are environmentally friendly, the cost is low, cyclic reuse can be achieved, and the net membrane is a novel oil-water separation net membrane which is more environmentally friendly and affordable.
Owner:SICHUAN UNIV

Ultrahigh temperature multi-dimensional multi-functional strain measurement system based on ultraviolet imaging DIC and measurement method

The invention relates to an ultrahigh temperature multi-dimensional multi-functional strain measurement system based on an ultraviolet imaging digital-image-correlation(DIC) method and measurement method. The strain measurement system comprises ultraviolet cameras (1,5), coaxial long-working distance microscopic lenses (7,15), a monochromatic source (2), narrowband pass filters (6,16) having wavelengths corresponding to that of the monochromatic source, and high temperature speckles or friction scratch spots on a surface of a test piece. A high temperature image observation furnace and a matched high temperature mechanical testing device are used to apply force and thermal load on the test piece having a rectangular cross section or a cylindrical surface. A coaxial ultraviolet light active illumination test piece is adopted, and the ultrahigh temperature multi-dimensional multi-functional strain measurement system based on the ultraviolet imaging digital-image-correlation(DIC) method is used to acquire the surface image of the test piece. By adopting the DIC method, the two-dimensional or three-dimensional measurement of the high-precision real-time millimeter to micron-level visual field of the strain of the surface of the test piece is carried out. A principle is simple, and a structure is compact. By adopting cooperation between a high temperature image furnace and a high temperature stretching device, the real-time, high-precision measurement of the deformation of the surface of the test piece and the mechanical performance of the test piece in environment at a temperature in a range from indoor temperature to ultrahigh temperature of 2000 DEGC is carried out.
Owner:BEIHANG UNIV

Method and system for range sensing of objects in proximity to a display

The invention relates to a method for sensing the range of objects captured by an image or video camera using active illumination from a computer display. This method can be used to aid in vision based segmentation of objects.
In the preferred embodiment of this invention, we compute the difference between two consecutive digital images of a scene captured using a single camera located next to a display, and using the display's brightness as an active source of lighting. For example, the first image could be captured with the display set to a white background, whereas the second image could have the display set to a black background. The display's light reflected back to the camera and, consequently, the two consecutive images' difference, will depend on the intensity of the display illumination, the ambient room light, the reflectivity of objects in the scene, and the distance of these objects from the display and the camera. Assuming that the reflectivity of objects in the scene is approximately constant, the objects which are closer to the display and the camera will reflect larger light differences between the two consecutive images. After thresholding, this difference can be used to segment candidates for the object in the scene closest to the camera. Additional processing is required to eliminate false candidates resulting from differences in object reflectivity or from the motion of objects between the two images.
Owner:IBM CORP

Nighttime double fruit overlap tomato identification method based on overlap edge detection under active illumination

The invention discloses a nighttime double fruit overlap tomato identification method based on overlap edge detection under active illumination. The method comprises the following steps of collecting a nighttime double fruit overlap tomato image under active illumination; using an OTSU method to perform image segmentation based on R-G color difference; performing image enhancement by using a homomorphic filtering method for the grayscale of the double fruit overlap tomato region extracted after image segmentation; extracting the edge, the contour and the overlapping edge of a spot area of the double fruit overlap tomato region after the image enhancement; judging the anteroposterior position relationship between the front unshielded tomato and the later-blocked tomato in the double fruit overlap tomato using a distance nearest method; and circularly fitting the overlapping edge and the front unshielded tomato contour to achieve recognition of the front unshielded tomato in the double overlap tomatoes. The method can realize the recognition of the front unshielded tomato in the double fruit overlap tomatoes at night, and has good recognition effect on overlap tomatoes with different overlapping rates, especially for double fruit overlap tomatoes with the large overlap rate.
Owner:CHINA JILIANG UNIV

Ultra-high-temperature strain field-temperature field synchronous measurement system and measurement method based on ultraviolet imaging

The invention relates to an ultra-high-temperature strain field-temperature field synchronous measurement system and measurement method based on ultraviolet imaging. The strain field-temperature fieldsynchronous measurement system comprises an ultraviolet camera (1), a lens (2), a coaxial ultraviolet light source (3), a narrow-band-pass filter (4) corresponding to the wavelength of the ultraviolet light source, and a computer (6) for processing an image to obtain a strain field-temperature field. Before a strain field-temperature field is measured, a high-temperature-resistant speckle (9) ismanufactured on the surface of a test piece (10); a high-temperature mechanical testing machine is used for applying force and thermal load to the tested piece; the coaxial ultraviolet light is adopted for active illumination of the test piece; the ultra-high-temperature strain field-temperature field synchronous measurement system based on ultraviolet imaging is used for collecting surface imagesof the test piece; and a digital image correlation method and a system calibrated by a blackbody furnace in advance are used for measuring the strain field-temperature field of the surface of the test piece in a high-precision millimeter-to-micron view field mode. The principle is simple, the structure is compact, and the strain field-temperature field of the surface of the test piece in the environment from the room temperature to the 3273K ultrahigh temperature is synchronously measured in a high-precision mode through cooperation of the high-temperature mechanical test device.
Owner:BEIHANG UNIV
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