14 results about "Subsurface scattering" patented technology

The invention relates to the technical field of tooth modeling, and discloses a three-dimensional tooth modeling system based on computer vision, computer equipment and a readable storage medium. According to the method, mirror reflection, diffuse reflection and subsurface scattering components in an original image are separated, mirror reflection intensity is normalized in combination with a dynamic truncation algorithm, pixel saturation is eliminated, groove and nest textures are reserved, a complete point cloud is obtained based on a two-dimensional texture image and cubic spline repair, and a multi-exposure point cloud sequence is obtained through bimodal calibration. The method comprises the following steps: solving the problem of data dislocation, carrying out weight assignment and data fusion on three-dimensional points in a plurality of exposure point cloud sequences to obtain three-dimensional fusion feature data, combining layered optical modeling and photon tracking compensation deviation, fusing clinical constraints, finally dynamically adjusting parameters, feeding back and optimizing, and outputting a micron-sized precision model. The modeling defect caused by difficulty in effectively coordinating feature contribution degrees under different exposure conditions is overcome, and high-precision modeling is realized.

The invention discloses a fringe projection three-dimensional shape measurement method based on frequency domain and time domain joint coding, and the method comprises the following steps: firstly, embedding a multi-frequency three-step phase shift fringe pattern in the vertical direction based on multi-scale region division, introducing four-step phase shift and complementary Gray code joint coding in the horizontal direction, generating a coding pattern set, and carrying out the projection; after an image is collected, frequency domain transformation and time domain decoding are carried out respectively, and a vertical dominant frequency position, a horizontal period number and a wrapped phase are obtained; then, combining a main frequency position in the vertical direction with a period number and a wrapped phase in the horizontal direction, and extracting a space coordinate of a direct illumination component based on frequency position invariance; and finally, establishing a pixel homonymy point mapping relation between the projector and the camera, and realizing high-precision three-dimensional reconstruction. Compared with a traditional frequency shift method, the method has the advantages that projection patterns are greatly reduced, reconstruction precision and anti-interference performance are improved, and the method is suitable for dynamic three-dimensional measurement under complex illumination conditions such as specular reflection, semitransparent shielding and subsurface scattering.

An electronic apparatus and method for generation of subsurface scattering texture maps for three-dimensional (3D) objects is provided. The electronic apparatus controls a set of light sources to generate a set of lighting patterns. The electronic apparatus controls a set of image capture devices to capture a set of images of an object that is illuminated by the generated set of lighting patterns. The electronic apparatus determines pixel-level offset information based on application of an image registration operation on the set of images. The electronic apparatus generates a set of corrected images based on the pixel-level offset information and the set of images. The electronic apparatus estimates subsurface scattering (SSS) parameters in a form of texture maps corresponding to a 3D mesh of the object. The estimation is performed based on a fitting of a scattering model on the set of corrected images.

The invention discloses a quantitative detection method for anti-perspective performance of a textile in a complex light environment, and belongs to the technical field of new material detection, a micro gap is arranged between the textile to be detected and a variable-frequency gray scale target to simulate a non-clinging state when clothes are worn and excite Fresnel diffraction and subsurface scattering effects, and the anti-perspective performance of the textile is detected. Complex illumination conditions such as backlight and sidelight are simulated by adjusting the light intensity ratio, and after a target perspective image is acquired by using an image acquisition unit, the modulation transfer function attenuation rate of a to-be-detected textile to the target is calculated, so that the anti-perspective performance of the textile is quantitatively represented; the interference of glare on the surface of the high-gloss fabric is effectively eliminated by introducing an orthogonal polarization modulation technology, and a detection result is highly consistent with the visual perception of human eyes by adopting a specific light source spectrum simulating the skin color of a human body; compared with a traditional light transmittance method, the method has the advantages that the dimension crossing from luminous flux measurement to image information fidelity evaluation is realized, and the accuracy, reliability and practicability of detection are remarkably improved.

The invention relates to the technical field of fruit quality detection, and discloses a fruit quality detection method and system based on multispectral structured light, and the method comprises the steps: firstly collecting a structured light image sequence and a spectral intensity image of a to-be-detected fruit, and solving an initial truncation phase field; performing subsurface scattering phase reverse compensation on the initial truncation phase field by using a spectral intensity image, and reconstructing a unit normal vector field of the surface of the fruit to be measured through unwrapping; carrying out physical reverse compensation on the spectral intensity image by utilizing a unit normal vector field and an illumination direction vector, and decoupling to obtain real spectral reflectivity distribution; and finally, outputting a comprehensive grading result of the to-be-detected fruit by fusing the geometrical morphology characteristics and the spectrum biochemical characteristics. According to the method, the phase is corrected by calculating the gray absorption item and the gradient scattering item of the image, so that the problem of phase drift caused by light permeation due to the semitransparent fruit skin is effectively solved, the depth measurement error caused by light diffusion in a medium is eliminated, and the fruit detection precision is further improved.

Disclosed herein are various embodiments relate generally to computer vision, graphics, image scanning, and image processing as well as associated mechanical, electrical and electronic hardware, computer software and systems, and wired and wireless network communications to form at least three-dimensional models or images of objects and environments and to identify, characterize, or differentiate material or tissues in objects and environments.

This invention discloses a method and system for detecting surface defects in a transparent hood based on three-dimensional scanning, belonging to the field of three-dimensional optical measurement technology. The method includes steps such as optical characteristic pre-scanning and partitioning, adaptive viewing angle planning and dynamic scanning, scattering sensing registration and signal separation, surface reconstruction and defect extraction. By establishing an anisotropic scattering model and calculating the scannability index, this invention solves the technical problem of traditional scanning viewing angle planning that only considers geometric visibility while neglecting the optical characteristics of the transparent material. It achieves an improvement in scanning viewing angle from geometric reachability to optical detectability, increasing the point cloud integrity rate and multi-view stitching accuracy in areas with high curvature. By dynamically adjusting laser power, exposure time, polarization state, focal length, depth of field, and sampling density in real time based on optical characteristic partitioning, it achieves adaptive matching between scanning parameters and the material's optical response, effectively suppressing subsurface scattering interference and improving the microcrack detection rate.

The invention discloses a mutton color decision-making method and system based on fuzzy logic, particularly relates to the technical field of computer vision, and is used for solving the problem that according to an existing mutton color automatic grading method, color feature distortion is caused by mirror reflection and subsurface scattering, and the grading accuracy is affected. A mutton surface digital image is collected and preprocessed, hue, saturation and brightness parameters based on an HSV color space are extracted to serve as an initial color feature set, a specular reflection highlight area and a subsurface scattering diffusion area are recognized, edge interweaving complexity and effective scattering path depth are calculated, and a high-definition image is obtained. And generating a color distortion compensation coefficient based on the parameters, carrying out linear adjustment on an initial color feature by using the coefficient, inputting the corrected feature into a fuzzy logic decision system, and outputting a mutton color grade result.

The present disclosure provides a model rendering method and device, computer equipment and a storage medium, wherein the method comprises: obtaining a three-dimensional model of a target face, and obtaining target rendering information corresponding to the three-dimensional model; the three-dimensional model comprises a plurality of vertices; the target rendering information is used to represent the display light intensity of each target vertex in the subsurface scattering range corresponding to the three-dimensional model; based on the target rendering information and a color tendency diagram of subsurface scattering, the color tendency corresponding to each target vertex is determined; the color tendency diagram is used to describe the mapping relationship between different display light intensities and color tendencies; based on the color tendency corresponding to each target vertex, the three-dimensional model is rendered to obtain a target rendering model of the three-dimensional model.

The application provides a rendering method and device of a three-dimensional model, equipment and a medium, and relates to the technical field of computers. The method comprises the following steps: assigning a physical-based rendering (PBR) material with a gelatinous texture to an initial three-dimensional model, adding a preset surface color map to the initial three-dimensional model, and obtaining a three-dimensional model to be rendered; obtaining a first rendering parameter based on a subsurface scattering algorithm; determining a first rendering area and a second rendering area of the three-dimensional model to be rendered based on a preset reflection algorithm, and determining a second rendering parameter corresponding to each pixel point; and rendering according to the first rendering parameter and the second rendering parameter to obtain a target three-dimensional model, so that the target three-dimensional model can present a subsurface scattering effect under different viewing angles through a regional rendering operation, and can also present a rendering effect of weak light transmission in thick places and good light transmission in thin places, so that the gelatinous texture is more realistic, and the rendering effect is not affected by viewing angle switching.

The application discloses a mutton color decision method and system based on fuzzy logic, and particularly relates to the technical field of computer vision, and is used for solving the problem that the existing mutton color automatic grading method is influenced by the color feature distortion caused by specular reflection and subsurface scattering and the grading accuracy; the mutton color decision method and system are realized by the following steps: collecting a digital image of a mutton surface and performing pretreatment, extracting hue, saturation and brightness parameters based on an HSV color space as an initial color feature set, identifying a specular reflection highlight area and a subsurface scattering diffuse area, calculating edge interweaving complexity and effective scattering path depth, generating a color distortion compensation coefficient based on the parameters, applying the coefficient to linearly adjust the initial color feature, and inputting the corrected feature into a fuzzy logic decision system to output a mutton color grade result.

The invention provides an object rendering method and device, electronic equipment and a medium, and the method comprises the steps: sampling a basic color map and an SSS map of a corresponding visual angle from a target polyhedron Imposter map set based on a real-time visual line direction of a virtual camera; calculating a forward diffusion component and a subsurface scattering component based on a light source direction and a sight line direction, and calculating a light and shade boundary component based on the light source direction and an outward normal vector of each vertex in the target polyhedron Imposter model, thereby determining a target three-direction illumination component; sampling from the SSS map based on a pre-configured Alpha value of the SSS map, and determining a mask value; and the basic color map is rendered based on the target three-direction illumination component and the mask value, and the rendered basic color map represents the corresponding target object in the real-time sight line direction, so that the bandwidth occupation standard exceeding and the illumination calculation degree during long-range object rendering are reduced, and the illumination authenticity is improved.

The application relates to the technical field of fruit quality detection, and discloses a fruit quality detection method and system based on a multi-spectrum structured light, which first collects a structured light image sequence and a spectral intensity image of a fruit to be detected, and calculates an initial truncated phase field; then performs inverse compensation of a subsurface scattering phase on the initial truncated phase field by using the spectral intensity image, and reconstructs a unit normal vector field of a surface of the fruit to be detected through unwrapping; then performs physical inverse compensation on the spectral intensity image by using the unit normal vector field and an illumination direction vector, and decouples to obtain a real spectral reflectance distribution; and finally fuses geometric and spectral biochemical features to output a comprehensive grading result of the fruit to be detected. The application corrects the phase by calculating a gray absorption term and a gradient scattering term of the image, effectively solves the phase drift problem caused by the penetration of light on the translucent fruit skin, eliminates the depth measurement error caused by the light diffusion in the medium, and further improves the fruit detection precision.

The application discloses a three-dimensional virtual image expression animation generation method based on a real feeling rendering technology, and comprises the following steps: inputting a speech segment and a three-dimensional virtual image head grid model, driving the head grid model to deform by using a speech signal, and generating a three-dimensional virtual image grid model sequence corresponding to the speech signal and containing expressions; inputting a single face image, and generating a diffuse reflection map conforming to a topological structure of the three-dimensional virtual image head grid model; respectively acquiring a specular reflection component, a subsurface scattering component and a transmission component, and constructing a skin rendering model based on the specular reflection component, the subsurface scattering component and the transmission component; rendering the three-dimensional virtual image grid model sequence based on the skin rendering model, and outputting a three-dimensional virtual image expression animation sequence with a high real feeling skin effect. The application meets various needs in practical applications.