43 results about "Orthogonal plane" patented technology

An apparatus includes an x-ray source configured to generate x-rays, at least some of which impinge a sample and at least one diffractor configured to concurrently diffract at least some of the x-rays from the sample in a first direction and in a second direction substantially orthogonal to the first direction. The apparatus further includes at least one two-dimensional (2D) position-sensitive x-ray detector configured to receive at least some of the diffracted x-rays and to concurrently generate first spectral information of the x-rays diffracted in the first direction and second spectral information of the x-rays diffracted in the second direction. The apparatus further includes circuitry configured to receive the first and second spectral information and to generate a single x-ray absorption spectroscopy (XAS) spectrum using the first and second spectral information.

The invention discloses a sparse view angle 3D-DSA reconstruction method based on a three-dimensional Poisson generative model. The method comprises the following steps: obtaining pairing data of a sparse view angle 2D-DSA projection drawing and a 3D-DSA reconstruction image; extracting features of a projection image by using a projection domain encoder, then converting features of two-dimensional projection into a three-dimensional image domain according to a geometrical relationship of the cone beam CT, and then obtaining a prior image by using an image decoder; the method comprises the following steps: constructing a three-dimensional Poisson generation model, adding noise to a three-dimensional image patch in a training stage to obtain a disturbance image, outputting a network reconstruction image by taking a prior image as a condition and the three-dimensional image patch before noise addition as a target image, and calculating loss of the output image and the target image to update network parameters; the mean square error loss and the mean square error loss of the maximum intensity projection images of the three orthogonal planes are used during loss calculation; in the sampling stage, random noise is used as input, a prior image is used as a condition, noise of a noise image is continuously denoised within a limited step length, and finally a reconstructed 3D-DSA image is obtained.

The invention relates to a point cloud target detection method and system fusing 2D features, and electronic equipment. The method comprises the following steps: performing voxelization processing on collected original point cloud data to generate a three-dimensional voxel feature tensor; respectively projecting the three-dimensional voxel feature tensors to three orthogonal plane view angles of front view, bird's-eye view and side view to generate a multi-view angle feature map; performing cross-view feature alignment and splicing on the multi-view feature map to generate a composite feature map; optimizing the composite feature map by using a channel attention weighting mechanism to obtain an optimized composite feature map; and target detection is carried out based on the optimized composite feature map, so that the technical problem that the detection recall rate of the target is reduced due to three-dimensional space information loss in a BEV perspective in a traditional method is solved, and the technical effect of improving the detection recall rate of the target in a sparse point cloud scene is achieved.

The invention provides a mitral valve leaflet length automatic measurement method based on 3D-to-2D morphological transformation. The method comprises the following steps: firstly, acquiring three-dimensional medical image data of the heart of a patient, and extracting six partitions of a mitral valve and related heart structures; an orthogonal plane is calculated by fitting a mitral valve structure point set, and a cKDTree algorithm is used to determine a connected area of each partition, and a corresponding projection plane is established. And then extracting the contour of the projection point set through an Alpha shape algorithm, correcting the contour into a linear three-dimensional point set, and finally calculating the length of the valve leaflet of each partition. According to the method, the accuracy, consistency and efficiency of measurement are improved through an automation technology, personal errors are reduced, the method is suitable for various three-dimensional medical image data, and a more reliable basis is provided for clinical diagnosis and treatment of mitral valve diseases.

Systems and methods are provided for determining fabrics of a geological sample using three-dimensional segmentation. An example method can include receiving three-dimensional (3D) image of a geological sample, adjusting an initial size of the 3D image of the geological sample, and partitioning the resized 3D image of the geological sample into cubes. The example method can include, for each cube, generating orthogonal planes based on a center of mass of each cube and extracting, for the orthogonal planes associated with each cube, one or more features to represent texture of the geological sample. The example method can further include grouping the cubes into one or more clusters based on the one or more features and constructing a volume of the resized 3D image of the geological sample based on the one or more clusters for a texture analysis of the geological sample.

The present invention discloses a monocular depth estimation method for intelligent transportation based on an orthogonal plane, including: S1, obtaining an RGB image and an image dataset with the same resolution as its lower frame; S2, constructing a global and local feature extraction module to obtain encoded features at four resolutions; S3, sending the encoder output features into a non-mobile window Transformer for generating pixel depth to obtain decoded features at three different resolutions; S4, by sending the decoder depth probability representation into a bins classification network, outputting an interval bins group through a lightweight Transformer combination, and performing a Hadamard product on the bins interval group and the depth representation to obtain a classified depth value; S5, determining the final depth value through a mixture Gaussian estimation of the imaging plane depth probability output by the decoder and the optical axis multi-plane depth probability output by the multi-plane bins. According to the present invention, the present invention provides instant and accurate target depth information for intelligent driving vehicles in the traffic field, providing strong support for the accurate positioning of targets and the three-dimensional scene reconstruction.

This invention discloses a three-dimensional modeling method for the true shape of boulders in a soil-rock fill slope, comprising: Step 1, acquiring the two-dimensional projections of the boulders of the actual soil-rock fill slope onto three orthogonal planes; Step 2, obtaining the coordinates of the two-dimensional projection contour points, calculating the centroid of the contour line, moving the centroid to the origin of the coordinate system, and recalculating the coordinates of the contour points; Step 3, segmenting the contour line into spatial regions based on the projections of the boulders on the XOZ and YOZ planes, and randomly reconstructing a contour line; Step 4, performing compatibility analysis on the XOY plane and correcting the reconstructed contour line; Step 5, randomly constructing several contour lines within each spatial region; Step 6, generating a three-dimensional geometric model with a true shape based on the contour lines. The method of this invention constructs a three-dimensional realistic model based on the true shape of the boulders, resulting in higher accuracy in subsequent finite element analysis of the stability of the soil-rock fill slope from a heterogeneous perspective.

The invention belongs to the technical field of block chain and artificial intelligence crossing, and particularly relates to a fair federal consensus method and system based on gradient projection. The objective of the invention is to solve the problem that the fairness of a global model is reduced due to unfair client contribution evaluation and improper projection target selection in a gradient conflict resolution mechanism under the condition of non-independent identically distributed data (Non-IID). The method comprises the following steps: initializing a client key and parameters; randomly selecting m clients for local training in each round; calculating an effort value according to the loss change and the accuracy rate, and preferentially assigning a block creator; the server detects gradient conflicts and performs selective projection resolution, and a gradient with a large length is projected to an orthogonal plane with a gradient with a small length; aggregating the conflict-free gradient to update the global model; and circulating to a preset round number and outputting a final model and a creator sequence. According to the scheme, model performance and participation fairness are considered, and consensus efficiency and excitation compatibility of federated learning in a heterogeneous environment are improved.

The invention discloses an experiment module solar wing double-shaft coupling sun-facing fixed angle servo control method and system, and aims to reduce mechanical wear by reducing rotation of a solar wing, reduce collision risk by reducing the projection area of the solar wing on an orbital plane orthogonal plane, reduce physical damage on the basis of meeting the power requirement, and improve the reliability of the solar wing double-shaft coupling sun-facing fixed angle servo control system. The task requirement for long-life operation of the space station is met, and the on-orbit life of the solar wing of the space station is prolonged. Namely, sun orientation control is completed by adopting a fixed rotation angle value and an intermittent rotation mode for the two degrees of freedom of the solar wing. The design process comprises the steps that firstly, a beta axis is designed to be in a fixed angle servo control mode, the rotation fixed angle of the beta axis is totally 2n + 1 gears, and the value range is {-n delta,...,-3 delta,-2 delta,-delta, 0, delta, 2 delta, 3 delta,..., n delta}; when the beta axis does not return to zero, setting the alpha axis to return to zero horizontally; when the beta axis returns to zero, if the alpha axis returns to zero horizontally and cannot meet the power requirement, the alpha axis is designed to be in a fixed angle servo control mode, the number of fixed rotation angles of the alpha axis is three, and the value range is {-angle alpha0 ', 0 and angle alpha0'}.

The invention discloses a mandibular canal segmentation method and system, electronic equipment and a storage medium. The method comprises the following steps: acquiring an oral maxillofacial region image; cutting the oral maxillofacial region image to obtain a plurality of local images of the mandible; inputting the plurality of local images into a mandibular canal segmentation model, and outputting to obtain a segmentation result; the mandibular canal segmentation model comprises an encoder, a decoder and a feature fusion module, three two-dimensional convolution branches are configured on three orthogonal projection planes in the feature fusion module, and each two-dimensional convolution branch can obtain boundary information, center trend and local bending features of the mandibular canal on different orthogonal planes and fuse the boundary information, the center trend and the local bending features to obtain multi-view features; and fusing the multi-view feature and the local texture feature to obtain an enhanced feature, fusing the local texture feature and the enhanced feature by a decoder, and outputting to obtain a segmentation result. And through the feature fusion module, comprehensive coverage of multi-view geometric features is realized, and the problems of segmentation fracture and boundary blur caused by single feature extraction are effectively avoided.

The present application belongs to the technical field of industrial detection, and particularly relates to a forging round steel straightness online detection method based on point cloud data, which comprises the following steps: firstly, obtaining original point cloud and multi-dimensional physical characteristic data of the round steel in a transmission state; then, slicing the point cloud, and combining local geometric missing features and thermal deformation driving features to calculate a compensation step, and correcting a primary centroid to obtain a real three-dimensional physical axis; subsequently, projecting the axis to an orthogonal plane, and using a restriction relationship between local curvature and material bending stiffness to obtain a pseudo-boundary penalty factor, and then correcting an envelope angle and calculating a comprehensive straightness error. The present application eliminates the interference of point cloud missing, thermal eccentricity and surface microscopic defects, and improves the accuracy of the forging round steel straightness detection.

The application relates to a three-dimensional extended target tracking method of an adaptive Gaussian process under unknown measurement noise. Firstly, a forgetting factor is adaptively updated by recursively calculating the change rate of the Cramer-Rao lower bound trace, so that the dynamic optimization of filter parameters is realized; then, a projection method based on GP is used to represent a three-dimensional cross-shaped target, three-dimensional point clouds acquired by a sensor are projected to three orthogonal planes, and the three-dimensional extended shape of the target is reconstructed by using two-dimensional contour information; finally, a robust state estimator is constructed by fusing variational Bayesian inference and MCC, the joint posterior distribution of unknown measurement noise and system state is solved by variational approximation, and a cost function is constructed based on the maximum correlation entropy criterion, so that the influence of abnormal values is inhibited in a reweighted manner. The tracking method provided by the application can significantly improve the tracking precision and robustness of a three-dimensional extended target under unknown strong non-Gaussian measurement noise.

The application relates to the technical field of image processing, and provides a face micro-expression recognition method and device, electronic equipment and a storage medium, the method comprising the following steps: acquiring a face micro-expression image sequence to be recognized; pre-processing the face micro-expression image sequence; extracting HCTP features of three orthogonal planes of the pre-processed face micro-expression image sequence; determining feature histograms in three dimensions based on the HCTP features; the HCTP features are image features obtained by combining CTP features on the basis of Haar features; the feature histograms in the three dimensions are standardized; the three feature histograms after the standardization are concatenated into a histogram vector; the histogram vector is input into a trained neural network model based on deep learning for classification; and a corresponding expression category is obtained. In this way, by considering the face micro-expression feature information of the three orthogonal planes and the central pixel information, comprehensive features are extracted, and the accuracy of face micro-expression recognition is improved.

An apparatus is disclosed for securing a tube of uniform cross section to a brickwork corner to serve as a profile. The apparatus comprises at least one collar for sliding onto the tube to define fixed reference surfaces to contact the two faces of the corner and to define adjustable abutments for contacting the two faces of the corner at a distance from the reference surfaces to permit adjustment of the attitude of the tube in two orthogonal planes, and a tensioning arrangement for applying a force directly or indirectly to the tube to urge the reference surfaces and the adjustable abutments into contact with the two faces of the corner.

The application provides a video rain removal method and system based on a space-time difference state space model, and belongs to the technical field of deep learning. The application solves the problem of how to ensure accurate rain removal while retaining the background texture to the greatest extent and breaking the trade-off between "rain removal completeness" and "background fidelity". The method comprises the following steps: S1: extracting shallow space-time features from an input video; S2: constructing anchor points and reference features by using multi-plane scanning, generating a gating map by calculating geometric consistency, and removing rain information in the features by using a difference mechanism; S3: during training, capturing local space-time details by using orthogonal plane convolution, during inference, enhancing the video background texture by using a single-stream convolution after reparameterization, and outputting a rain-removed video. The system comprises a 3D convolution layer module, a consistency-guided difference gating module, and a reparameterized three-plane feedforward network.

The invention relates to the technical field of point cloud models, in particular to a river topography three-dimensional point cloud dynamic reconstruction method, which comprises the following steps of: acquiring original three-dimensional point cloud data of a target river, and constructing a manifold triangular mesh based on the original three-dimensional point cloud data; according to the method, the complex three-dimensional river form is collapsed into the one-dimensional point column set, the central axis skeleton line is extracted, the topological trend and the central trend of the river can be captured, the orthogonal plane is generated in the tangential direction of the central axis skeleton, the section contour is extracted through the Alpha-Shape algorithm, and parameterized dimension reduction expression of the geometric form of the river is achieved; according to the method, the contour of each section is connected by using a spline interpolation algorithm by taking the central axis skeleton as a scanning path, and the three-dimensional surface model of the river topography with a continuous topological structure is generated, so that the precision and availability of the model in hydrodynamic analysis and engineering calculation are improved, and the technical problem that unstructured scattered point clouds are difficult to be directly used for hydrological feature extraction is solved.

The invention belongs to the technical field related to master-slave control of medical equipment, and discloses a puncture needle track prediction and master-slave control method based on force measurement, which comprises the following steps of: (1) measuring bending moment and transverse force in two orthogonal planes of a puncture needle tail end coordinate system and axial force along a puncture needle in real time; (2) calculating to obtain a simulation load loaded on the interaction part of the puncture needle and the soft tissue; (3) respectively solving the predicted positions of the puncture needle on the two corresponding orthogonal planes; and (4) the predicted position and the expected position are subtracted, the obtained difference value is multiplied by a proportionality coefficient to obtain two pieces of force sense information, then the two pieces of force sense information and the axial force are transmitted to the master-end operation equipment, the master-end operation equipment carries out force sense reproduction according to the received information, the force sense information serves as an operation instruction of an operator to the slave-end robot, and the operation instruction of the operator to the slave-end robot is completed. And the attitude of the slave end robot is controlled to reduce the difference value between the predicted position and the expected position. According to the invention, the real-time performance is improved.

The polarization beam splitter comprises a uniform two-dimensional grating layer, a substrate dielectric layer and a non-uniform two-dimensional grating layer which are stacked in sequence, and the uniform two-dimensional grating layer is formed by periodically and uniformly arranging a plurality of nano columns with the same size in a square shape. The uniform two-dimensional grating period is equal to half of the super-structure grating period; the uniform two-dimensional grating layer is formed by distributing nine nano-columns on the outer surface of a cubic cell of the super-structure grating, and the nine nano-columns comprise first nano-columns located at four vertexes of a square, middle points of four side lengths of the square and the center of the square; the non-uniform two-dimensional grating layer is constructed on the substrate dielectric layer and is formed by periodically arranging a plurality of nano columns with different sizes in a square shape, the periodic arrangement formed by each nano column is mutually shifted by a half period in the horizontal direction, and the period of the non-uniform two-dimensional grating layer is equal to the period of the super-structure grating. Compared with the prior art, the two-dimensional grating constructed by the invention has a large design freedom degree so as to flexibly adjust the transmission efficiency of each diffraction order, and has the advantages of high extinction ratio, small volume, easiness in integration, polarized light beam splitting on two orthogonal planes and the like.

The invention provides an optical element driving device, a camera module and a camera mounting device, which can restrain reduction of inclination characteristics and deviation of an optical axis, and can enable an optical element to move in the optical axis direction in a stable posture. The optical element driving device includes: a base; a holder on which the optical element can be mounted; a plurality of support parts that are disposed at rotationally symmetrical positions on the outer peripheral surface of the holder and that support the holder so as to be movable in the optical axis direction with respect to the base; and a drive unit that moves the holder in the optical axis direction. The support portion has: a ball; a ball receiving section that supports the balls so as to be capable of rolling in the optical axis direction; and a biasing part that presses the ball toward the ball receiving part. In an optical axis orthogonal plane orthogonal to the optical axis direction, a second component orthogonal to the radial direction is larger than a first component parallel to the radial direction passing through the optical axis and the center of the ball.

The present invention discloses a method for detecting the grasping state of a flexible manipulator in different postures and motion states, and belongs to the field of tactile signal analysis and processing based on flexible manipulators. The present invention conducts grasping state classification and recognition experiments in five static scenarios: horizontally upward, horizontally downward, horizontally left, horizontally right, and horizontally; and in six dynamic scenarios: translational reciprocating motion in three axial directions, front-back, left-right, and up-down, and semicircular arc reciprocating motion in three orthogonal planes in space. The present invention greatly broadens the experimental scenarios, making the experimental results highly generalizable and universal. The present invention proposes a self-adaptive standardized high-dimensional fuzzy system, and for the first time uses a fuzzy system to solve the problem of grasping state detection of a flexible manipulator. Compared with the grasping state detection results using other machine learning methods, the classification accuracy of the results is higher.

[Problem] To increase the reliability and throughput of measurement of the properties of a film formed on a substrate. [Solution] A substrate is illuminated with polarization components consisting of p-polarization and s-polarization of terahertz waves with mutually orthogonal planes of vibration. Time waveforms of the electric field intensities of the p-polarization and the s-polarization are acquired from a time waveform of the electric field intensity of a polarization component reflected from the substrate. A spectrum of an actually measured amplitude ratio of the p-polarization and the s-polarization, and a spectrum of an actually measured phase difference between the p-polarization and the s-polarization are acquired. A spectrum of a calculated amplitude ratio of the p-polarization and the s-polarization, and a spectrum of a calculated phase difference between the p-polarization and the s-polarization are acquired through simulation using an optical model of the substrate. The properties of a film formed on the substrate are measured by fitting involving at least alignment of the spectrum of the calculated amplitude ratio with the spectrum of the actually measured amplitude ratio. Among a plurality of measurement values used in the measurement of the properties of the film, those with high reliability are employed.

Presented herein are systems and methods of generating regions of interest (ROIs) in biomedical images of volume structures within a subject. One or more processors may identify a plurality of biomedical images of a volume stucture within a subject. The one or more processors may receive a plurality of tracings. The one or more processors may determine a plurality of curves to identify the ROI within the volume structure in accordance with a curve morphing function based at least on the plurality of tracings. The one or more processors may generate the ROI using the plurality of curves determined within the volume structure. The one or more processors may store, using one or more data structures, an association between the subject and the ROI.

The invention discloses a parametric modeling method based on three-view adaptive projection, which is suitable for a task of automatically generating a structured modeling instruction from three-dimensional point cloud data and can realize CAD (Computer Aided Design) structure reconstruction with high geometric consistency and semantic interpretability. The method comprises the following steps: firstly, extracting global features by using a point cloud encoder to predict a rotation attitude in an Euler angle form, and performing rotation alignment on a point cloud; then projecting the rotated point clouds to three groups of orthogonal planes respectively, extracting a high-quality projection point set by combining adaptive grid sampling of normal filtering and density sensing, extracting structured two-dimensional features by adopting a hierarchical K-nearest neighbor aggregation mechanism based on a three-view projection result, and further guiding a parameter decoder to generate a sketch and a stretching modeling instruction; the method has the remarkable advantages in the aspects of structure alignment precision, complex geometry adaptability and program editability, and is suitable for application scenes such as reverse design, industrial part modeling, building sketch reconstruction and intelligent auxiliary modeling.

To provide a branch chamber enabling a flow rate from an outflow port to become uniform without requiring an extra space on upper and lower sides and regardless of small pressure loss.SOLUTION: Within a chamber body of a branch chamber, when a surface in parallel with an inner surface of a tip wall part 24 is defined as an orthogonal surface, flow rate uniformizing means 40 for making a flow rate of air flowing on the orthogonal surface uniform is disposed before an outflow port formed at a position nearest to an inflow port 30, and guide means 50 for changing a moving direction by hitting part of air for guiding to the outflow port is disposed between the plurality of outflow ports 32A, etc.SELECTED DRAWING: Figure 2

The present invention comprises a plurality of light source bodies (2) that are aligned in a prescribed direction and a lens (3) that has no curvature in the prescribed direction, has curvature in a plane that is orthogonal to the prescribed direction, and focuses light of components that are emitted from the light source bodies (2) and advance along the orthogonal plane. An optical constant of the lens (3) as seen from the prescribed direction is defined such that the area of an aberration curve is greater on the positive side than on the negative side on a longitudinal aberration diagram for which the origin is the intersection of the optical axis (C) of the lens (3) and the surface of a workpiece, the horizontal axis is the optical axis (C), the direction in which light advances being the positive side, and the vertical axis is a normalized pupil coordinate.

The present invention proposes a method for automatically measuring the length of the mitral valve leaflets based on 3D to 2D morphological transformation. The method first obtains three-dimensional medical image data of the patient's heart and extracts six partitions of the mitral valve and related heart structures. By fitting the mitral valve structure point set, the orthogonal plane is calculated, and the cKDTree algorithm is used to determine the connecting areas of each partition, and the corresponding projection plane is established. The contour of the projected point set is then extracted by the Alpha shapes algorithm and corrected to a linear three-dimensional point set, and finally the length of each partitioned leaflet is calculated. This method improves the accuracy, consistency and efficiency of measurement through automation technology, reduces human errors, is applicable to a variety of three-dimensional medical imaging data, and provides a more reliable basis for the clinical diagnosis and treatment of mitral valve disease.

The present invention contributes to suppressing misinsertion of a locking mechanism. The first assembly member (10) has: an orthogonal wall (11) provided with an orthogonal plane (11a); a through-hole (12) provided in the orthogonal wall; a partition wall (13) as a first locking part (31) that divides the through-hole into a first through-hole (12a) and a second through-hole (12b); and a protruding portion (14) protruding from the orthogonal plane, the second assembly member (20) having an abutting wall (22) with a distal end abutting against the orthogonal plane of the first peripheral edge portion (17a), the second locking portion having: a locking piece (32a) inserted into the first through-hole; and a locking claw (32b) which is provided at the free end of the locking piece extending from the first through-hole and which hooks and locks the first locking part, and a protruding part (14) which protrudes from an orthogonal plane of the third peripheral part (17c) closer to the second through-hole than the first through-hole, and locks the tip of the contact wall when the second locking part is inserted into the second through-hole, and the protruding part (14) protrudes from the orthogonal plane of the third peripheral part (17c) and locks the tip of the contact wall when the second locking part is inserted into the second through-hole. The second assembly member is made to float when inserted into the first through hole relative to the second locking portion.

The present invention discloses a modeling method of a three-dimensional point cloud cutting model based on orthogonal surfaces, which realizes the authenticity of cutting simulation in virtual surgery. The method comprises: first, establishing orthogonal planes α, β, and γ centered on the scalpel tip according to the cutting direction and angle of the scalpel; then calculating the offset of each voxel point and the three orthogonal planes; then constructing a suitable incision shape function and cutting influence domain, judging whether the point needs to be displaced according to the three offsets of each voxel point, and if so, calculating its displacement, and performing displacement operations until all voxel points are traversed; finally, constructing a two-dimensional height field grid to render the cut surface. The modeling method of a three-dimensional point cloud cutting model based on orthogonal surfaces provided by the present invention obtains a relatively realistic incision shape by introducing a suitable incision shape function and a cutting influence domain; and obtains a relatively smooth incision rendering effect by introducing a two-dimensional height field grid to render the cut surface.

The present invention provides a method for extracting and identifying micro-expression features based on deep learning, comprising the following steps: constructing a four-layer pyramid optical flow model based on key frames, inputting micro-expression video key frames, and obtaining optical flow features; extracting LBP features from three orthogonal planes of a micro-expression image sequence, and cascading the normalized feature gradient histograms obtained in three dimensions into LBP-TOP histogram vectors; converting the optical flow features into a histogram, and cascading and fusing them with the LBP-TOP histogram vectors of the image sequence to obtain a histogram representation of the fused features; constructing a shallow CNN model based on a residual module, introducing a macro expression data set and a micro expression data set, and constructing a cross-dataset micro expression recognition model based on a CNN-GCN transfer learning network; inputting the fused features into a trained cross-dataset micro expression recognition model based on a CNN-GCN transfer learning network for classification, and obtaining micro expression types. This method effectively improves the recognition accuracy of micro expressions.

A system and method for generating sample data for analysis provide an image capture unit configured to capture a stack of images in image layers through a thickness of a sample, each image layer comprising pixel data in two orthogonal planes across the sample at a given sample depth; a processing unit configured: a) to process the captured pixel data to determine therefrom a pixel value of the energy of each pixel of the image, b) to select from each group of pixels through the stack of images the pixel having a highest energy; and c) to generate an output image file comprising a set of pixel data obtained from the selected pixels, wherein the output image file comprises for each pixel, the pixel position in the two orthogonal planes, the pixel vale and the depth position of the pixel in the image stack. The depth position of the selected pixel is provided in a fourth channel of the output image file, which represents a topography of a sample. An analysis unit comprises an input for receiving the output image file and to determine therefrom sample data, including identification of constituents in the sample and / or quantity of said constituents in the sample; and preferably comprises an artificial intelligence.