132 results about "Photometric stereo" patented technology

A 3-dimensional scanner capable of acquiring the shape, color, and reflectance of an object as a complete 3-dimensional object. The scanner utilizes a fixed camera, telecentric lens, and a light source rotatable around an object to acquire images of the object under varying controlled illumination conditions. Image data are processed using photometric stereo and structured light analysis methods to determine the object shape and the data combined using a minimization algorithm. Scans of adjacent object sides are registered together to construct a 3-dimensional surface model.

The present invention presents a framework for separating specular and diffuse reflection components in images and videos. Each pixel of the an M-channel input image illuminated by N light sources is linearly transformed into a new color space having (M-N) channels. For an RGB image with one light source, the new color space has two color channels (U,V) that are free of specularities and a third channel (S) that contains both specular and diffuse components. When used with multiple light sources, the transformation may be used to produce a specular invariant image. A diffuse RGB image can be obtained by applying a non-linear partial differential equation to an RGB image to iteratively erode the specular component at each pixel. An optional third dimension of time may be added for processing video images. After the specular and diffuse components are separated, dichromatic editing may be used to independently process the diffuse and the specular components to add or suppress visual effects. The (U,V) channels of images can be used as input to 3-D shape estimation algorithms including shape-from-shading, photometric stereo, binocular and multinocular stereopsis, and structure-from-motion.

The present invention relates to systems and methods for photometric endoscope imaging. The methods can further include chromoendoscopy and computer aided detection procedures for the imaging of body lumens and cavities.

The invention provides a luminous flux control method of a high definition vehicle snapshot system, belonging to the image processing field. The control method comprises the following steps: initializing the parameters of a camera, setting an initial photometric range and a photometric luminance reference value table; obtaining the current shutter speed value, gain value, reference datum value and current photometric interval of the camera; determining the photometric range of an acquired image; calculating photometric luminance value in the designated area of the photometric range; calculating the luminous flux control parameter; sending a control command, waiting in the designated photometric interval, and performing the next adjustment process. The method automatically adjusts the shutter and gain of the acquisition equipment and adjusts the light complement equipment according to the photometric result of a special area so that the pictures shot at any moment have proper exposure luminance, the problem that the exposure effects of the plate number and portraits in a vehicle on the traditional image are not consistent is solved; and the control method can be realized in the embedded system, thus the combination control of multiple devices becomes easy.

The invention relates to an underwater three-dimensional reconstruction device and method based on a structured light technology and a photometric stereo technology. The underwater three-dimensional reconstruction device provided by the invention comprises a cuboid-shaped frame, wherein a sliding rail is arranged at the top of the cuboid-shaped frame, a laser transmitter and a high-definition camera are arranged on the sliding rail, a rotatable circular sliding rail is arranged below the sliding rail, and the light ray pattern of the laser is a line pattern. At least six LED parallel shiny side light source lamps are arranged on the circular sliding rail and are white light lamps, and spaces between every two adjacent LED parallel shiny side light source lamps are equal. The underwater three-dimensional reconstruction device provided by the invention can carry out underwater laser structured light three-dimensional reconstruction and underwater photometric stereo three-dimensional reconstruction. The underwater three-dimensional reconstruction method provided by the invention comprises the following steps: calibrating equipment in the device and water quality conditions, detecting a target object in a target water area, namely carrying out laser structured light detection, photometric stereo detection and fusion of two detection results, and realizing high-accuracy three-dimensional imaging of the target area. The underwater reconstruction device and method provided by the invention can realize multiple underwater reconstruction methods; and compared with the previous methods, the object boundary restoring accuracy is greatly improved, and more accurate three-dimensional information is obtained.

The invention relates to an underwater high-precision 3D reconstruction device and method. The device comprises a prismatic frame, the top of the frame is provided with a bar-shaped slide rail, a high-definition camera whose position can be adjusted horizontally is mounted on the slide rail, a laser is fixed to one prism under the slide rail, eight spotlights are fixed to the prismatic frame under the high-definition camera, top points at the top of the prismatic frame are connected to the bottom of a flange via supports respectively, the top of the flange includes a bearing terminal, the top end of the bearing terminal is connected with a main umbilical cable, and the bottom of the bearing terminal includes a branching cable. The method comprises calibrating the laser, calibrating direction of incident light, putting the device into the sea, collecting a laser image of a target object and images under different illumination directions, and carrying out rapid high-precision 3D reconstruction via structural light and photometric technologies after that the images are sent to overwater positions. According to the invention, different underwater reconstruction methods are realized, advantages of photometric technology and structural light method are combined, and a reconstruction result is more accurate.

A system (100) is provided for imaging a patient's interior. The system comprises an imaging sensor (120) for acquiring a series of images of a region of interest (020) in the patient's interior, and a plurality of light sources (140) for illuminating the region of interest in the patient's interior from different light source directions (152-156). A light controller (160) is provided for controlling individual ones (142-146) of the plurality of light sources (140) to dynamically vary the light source directions (152-156) during said acquiring. Moreover, a processor (180) is provided for obtaining lighting data (164) indicative of the dynamically varying light source directions. The processor (180) is further arranged for using the lighting data to apply a photometric stereo technique to the image data so as to establish a three-dimensional [3D] surface profile of the region of interest. The processor (180) is further provided to detect insufficiently illuminated areas of the region of interest (020-024) in the images acquired by the imaging sensor (120), using the 3D surface profile of the region of interest. Accordingly, the system is enabled to establish a 3D surface profile of the region of interest from a series of images in a convenient and cost-effective manner.

The invention discloses a three-dimensional reconstruction method of a moving target under a variable illumination condition. The three-dimensional reconstruction method comprises the following steps of: collecting images of the moving target in multiple visual angles under the variable illumination condition provided by a light source; establishing an initial three-dimensional model of the moving target according to the images of the moving target in multiple visual angles, wherein the images are collected by multiple cameras at each moment; obtaining multiple illumination images of the moving target at each moment through utilizing movement estimation and movement compensation; recovering by uniting the initial three-dimensional model and multiple illumination images to obtain normal information of the initial three-dimensional model; and carrying out combined optimization on geometrical information of the initial three-dimensional model and the normal information of the initial three-dimensional model to obtain an optimized three-dimensional model of the moving target. The invention also discloses a three-dimensional reconstruction device of the moving target under the variable illumination condition. In the method and device provided by the invention, advantages of multiple-visual-angle three-dimensional and luminosity three-dimensional methods are combined and the movement estimation and the movement compensation under the periodical variable illumination condition are combined so that the reconstruction of a high-precision three-dimensional model of the moving target is realized.

There is described a method and 3D image acquisition system for addressing the specular nature of metallic surfaces in general, and ballistic pieces of evidence in particular, using photometric stereo by identifying and solving a plurality of sets of non-linear equations comprising a diffusive term and a specular term to determine a surface normal vector field N(x, y), and using N(x, y) to determine a 3D topography Z(x, y).

The invention provides a finger multi-feature comprehensive three-dimensional reconstruction method comprising the following steps: step 1, calibrating a multi-view multi-spectral finger acquisition device; step 2, performing feature matching on the surface texture image of the finger by adopting a multi-view three-dimensional reconstruction algorithm to obtain a sparse three-dimensional point cloud of the surface of the finger and complete multi-view three-dimensional reconstruction; step 3, performing three-dimensional reconstruction on the surface of the finger by adopting a photometric three-dimensional method to obtain dense depth information; step 4, fusing the three-dimensional point cloud subjected to multi-view three-dimensional reconstruction with the dense depth information obtained by the photometric three-dimensional method to obtain a fused three-dimensional Mesh model; and step 5, mapping the surface texture image and the internal vein texture image of the finger to thefused three-dimensional Mesh model to obtain a finger multi-feature comprehensive three-dimensional model. According to the method, the dense three-dimensional model is obtained by fusing multi-view three-dimensional reconstruction and photometric three-dimensional reconstruction so that the situation that the recognition accuracy is reduced due to the three-dimensional modeling method is reduced.

A system for extracting a 3D shape of a hot metal surface, includes: a light source unit emitting four types of light, i.e. two types of light each having different wave bandwidths that are different from a wave bandwidth emitted by a hot target object, and two other types of light having the same wave bandwidths as the above-described two types of light, respectively, so that the types of light having the same bandwidths are polarized in different directions so as not to interfere with one another; an image acquisition unit simultaneously emitting the four types of light, polarized from the light source, onto the target object so as to acquire 2D images of the target object; and an image processing unit using a photometric stereo technique so as to combine the 2D images acquired by the image acquisition unit and extract a 3D shape of the surface of the target object.

A near field non-standard light source-based in situ obtaining method for three dimensional polishing scratch shapes is disclosed. Six LED lights uniformly distributed on a hand held microscope are used as light sources, an illumination model for non-standard light sources is built in near field conditions, relative spatial positions of the light sources are calibrated, the hand held microscope isused for collecting image data of worn-out surfaces of parts, a Mask image is obtained based on image processing technologies, images under the same viewpoint and different light sources are subjected to background difference processing operation, an object image which requires three dimensional rebuilding is obtained, and a final three dimensional polishing scratch shape is rebuilt via iterationbased on combination of a technology for estimating a normal direction based on an image sequence and a technology of recovering surface shapes from the normal direction. According to an actual lightsource position, the illumination model for the near field non-standard light sources is built via use of the method disclosed in the invention after photometric stereo visual near field non-standardpoint light sources are adopted, the method can meet requirements of real measurement conditions, and calculation precision of normal vector and depth information of worn-out surfaces can be improved.

The invention discloses a measurement texture geometric feature reconstruction method based on photometric stereo. The method is characterized in that utilizing a realistic texture measuring device in a camera light source array mode to collect BTF data under different angle light sources and viewing angles; with measurement texture multi-view angle information being combined, optimizing a photometric stereo method and reconstructing normal information of the measurement texture; and reconstructing depth information of the measurement texture through a least square method in a measurement gradient field according to the normal information. More accurate normal information can be calculated when the input image sequence is influenced by non-Lamertian diffuse reflection parts of highlight and shadow and the like in the stage of calculating shadow information of the surface of the texture, and in the stage of calculating the depth information, influence of noise of the measurement gradient field on the depth is reduced through filtering.

The invention discloses a mobile three-dimensional reconstruction method based on multi-view photometric stereo. The method comprises the steps of camera parameter calibration and light source calibration; Collecting images, recording the first frame as a reference frame, and shooting a plurality of images around the reference frame; Obtaining the camera pose of each frame and the sparse three-dimensional point cloud of the target object; Performing single-frame normal estimation; And carrying out three-dimensional reconstruction on the target object, and completing the three-dimensional reconstruction under the reference frame visual angle through the above steps. According to the invention, high-precision three-dimensional reconstruction of the target object is completed in the moving state of the camera. According to the method, the requirement of the photometric stereo technology on equipment is simplified, only one camera and one light source are needed, and then the portability of the equipment in actual use is improved; Meanwhile, the method makes full use of the acquired camera pose and point cloud information, optimizes the calculation methods of key parts such as matching, improves the overall calculation speed of the method, enhances the practicability of the multi-view photometric stereo method, and can be further applied to real-time three-dimensional reconstruction application.

The invention discloses an image reflection removing device and a method based on photometric stereo, which belong to the technical field of machine vision and video image processing. Four light sources with consistent light intensity are firstly mounted at proper positions, and the illumination angle of each light source is determined through light source calibration; a picture is photographed in a condition in which the four light sources are lighted separately, Gaussian filtering is used to pre-process the obtained four images to remove white noise, the gray adjustment parameter of each pixel is then solved, and according to the parameter, the gray value of a point with reflection existing possibly is adjusted; and the four images after processing form an overdetermined equation according to a photometric stereo algorithm, an albedo graph is solved, and images with reflection removed are thus acquired. On one hand, the four images are used as the photometric stereo to remove reflection, and good robustness is realized in shadows formed by occlusion and a complicated pattern; and on the other hand, decoupling between the image and the light source is realized, and a more accurate reflection-removed image can be acquired.

The invention relates to a pavement scanning system having a movable platform, multiple light sources mounted on the platform for illuminating a pavement surface from multiple different angles, at least one image capture device mounted on the platform that captures sequential images of the illuminated pavement surface and a movement sensor that encodes movement of the platform and provides a synchronization signal for synchronizing the multiple light sources and the at least one image capture device for multiple image capture. The pavement scanning system also includes at least one processor that resamples the multiple captured sequential images to compensate for difference in collection time and calculates surface gradient and albedo for each point on the pavement surface or directly uses the multiple images to detect surface features.

The invention discloses a visual system based on photometric stereo vision. The system includes a spot generator which can project dense spots, at least three LEDs of which each forms a point light source, two cameras which constitute a pair of stereo cameras, and a control circuit which is in communication connection with the spot generator, the at least three LEDs and the two cameras in order to make the spot generator project dense spots, make the at least three LEDs turned on in turn and only one LED turned on at the same time, make the two cameras triggered simultaneously to collect an image of the surface of an object under the irradiation of the spot generator and make one of the two cameras triggered to collect an image of the surface of the object under the irradiation of the LEDs. The invention further discloses a corresponding 3D reconstruction method. The visual system of the invention is small, and has a fast measurement mode and an accurate measurement mode.

A welding device and a method for automatic multiple-bead welding, wherein a line illumination member is arranged to illuminate the joint by scanning a light beam across the joint line. A camera is arranged for the registration of line images of the joint when it is illuminated with the scanned light beam. The locations of the edges of the joint are determined by means of triangulation based on the registered line image. The welding device can include a stereo image member arranged to register photometric stereo images of the joint substantially simultaneously with the registration of the line images. The welding device is arranged to, during welding of a weld joint with a plurality of weld beads, control the welding head in dependence on both stereo images and line images.

The invention relates to the technical field of computer vision. The embodiment specifically discloses a method and a system for three-dimensional reconstruction of a human face based on binocular stereo and photometric stereo. The initial depth image of a target human face is obtained by binocular stereo matching. Four images of the target face collected by two light sources and two camera devices are represented by photometric stereo as constraint terms and combined with the initial depth image to construct the energy function of the depth image to be solved. The optimized depth image is obtained by minimizing the energy function, and the optimized depth image is transformed into a three-dimensional point cloud to obtain the three-dimensional point cloud of the target face. It solves theproblem that the existing photometric stereo vision needs at least three light sources for 3D reconstruction, and the scale-free feature has deformation, and realizes the accurate 3D reconstruction of human face without deformation.

The invention discloses a group sparsity based photometric stereo method for realizing non-Lambert object reconstruction. The method comprises steps as follows: normalized intensity of each pixel of a non-Lambert object in different light source directions is extracted and is grouped, highlight detection is realized with a group sparsity method, and normal restoration and three-dimensional reconstruction are completed finally. According to the method, structural information of the light source direction is sufficiently utilized, and the reconstruction of the complex non-Lambert object can be realized through a smaller number of light sources, so that the reconstruction of objects with different reflection characteristics can be realized with lower cost in shorter collection time.

The invention discloses a solar unmanned aerial vehicle which comprises an unmanned aerial vehicle body; a solar cell panel is arranged on the upper surface of the unmanned aerial vehicle body; a direction adjusting base is arranged under the solar cell panel; a photometric sensor is arranged at the front end of the solar cell panel; a control circuit is arranged inside the unmanned aerial vehicle; a photoelectric conversion component is arranged on one side of the control circuit; a large-capacity storage plate is arranged on the photoelectric conversion component. The solar unmanned aerial vehicle disclosed by the invention is simple in mounting and disassembly, the photometric sensor can sense solar rays and automatically adjust the direction of the solar cell panel, so that the collecting quantity of solar energy is increased; a communication device and a radar early warning device can increase safety coefficients and record flight lines in real time.