89 results about "Measurement plane" patented technology

The invention discloses an MAP scoring method and device based on kidney three-dimensional modeling, and belongs to the field of medical image processing. The method comprises the following steps: acquiring kidney medical image data, wherein the kidney medical image data comprises kidney CT image data; preprocessing the kidney medical image data; generating a complete kidney three-dimensional model based on the kidney medical image data; calculating the centroid positions of all voxels in the renal vein three-dimensional model, and taking the Z coordinate of the centroid as a standard measurement plane; identifying an anatomical region needing to be measured on the standard measurement plane based on a deep learning segmentation model; extracting an outer contour of the kidney based on the kidney three-dimensional model, determining a posterior abdominal wall contour based on the front edge of the lumbar major muscle, and calculating the shortest distance between the outer contour of the kidney and the posterior abdominal wall contour; and determining a perirenal fat region, enhancing the strip-shaped structure by using a multi-scale filter, and calculating the proportion of the strip-shaped structure in the perirenal fat region. According to the invention, objective quantitative evaluation of perirenal fat adhesion risk is realized.

The invention discloses a magnetic field inversion current method based on near-field scanning, and the method comprises the steps: obtaining magnetic field data in a circuit, and taking the magnetic field data as input; expanding the measurement plane of the magnetic field to obtain a magnetic field matrix, and enabling the current of the original magnetic field matrix H on the boundary to be continuous; constructing a relationship between the magnetic field and the current in the frequency domain space; a Tikhonov regularization method is used to reconstruct current distribution, and a GCV method is used to optimally select regularization parameters required by the Tikhonov regularization method; extracting structure information of the static current model, taking the structure information as a mask, and acting the structure information on a radio frequency current model result; and outputting the current in the original measurement window as the current reconstructed by the final method. Current artifacts on a boundary are eliminated by expanding a measurement plane, current distribution is automatically solved through regularization, errors caused by empirical selection of filtering parameters are avoided, the precision of reconstructed current is improved, and finally, spatial noise is suppressed through a mask method, and accurate reconstruction of radio-frequency current is achieved.

Measuring device for measuring at least one property of an optical element, wherein the device comprises: - a frame; - a supporting device arranged for supporting the optical element on the frame; - a rotating body arranged to rotate relative to the frame around a rotation axis; - a measurement system arranged to measure the relative position of the rotating body and the frame in at least one measurement plane; - a probe arranged on the rotating body for measuring the at least one property of the optical element, wherein the probe is located at a position out of the at least one measurement plane.

The invention belongs to the technical field of degaussing, and relates to a ship winding degaussing current solving method based on a gradient tensor, which comprises the following steps: acquiring the magnetic gradient tensor of a plane ship when coils are not electrified; respectively performing simulation electrification on the winding coils to obtain the magnetic gradient tensor of the electrified measurement plane; and calculating an efficiency matrix of the magnetic gradient tensor excited by the unit current. The gradient of the geomagnetic field is extremely small, direct detection of the magnetic gradient tensor of the ship and the electrified coil can better reflect the magnetic characteristics of the ship and the coil compared with detection of a magnetic vector, and better resolution is achieved for magnetic field changes caused by magnetic anomalies; under the motion platform, the magnetic gradient tensor is insensitive to the attitude angle error, and more accurate detection data can be obtained; in addition, the gradient tensor is weak in response to time-varying geomagnetic disturbance, and has higher anti-interference capability. Therefore, according to the method, the accuracy of ship magnetic field modeling and degaussing current calculation is improved, and the magnetic stealth performance of a ship facing high-sensitivity magnetic gradient detection equipment is enhanced.

The invention discloses a plane inclination angle measuring method based on laser ranging. According to the method, firstly, three laser ranging modules are placed on a measuring plane, and the relative positions of the three laser ranging modules are fixed; then, establishing a three-dimensional Cartesian coordinate system by using the modules, and measuring an included angle between the three-dimensional Cartesian coordinate system and a coordinate axis; then, calculating the coordinates of the module in the coordinate system, and calculating the included angle between the coordinates and the included angle to obtain a unit normal vector of the measurement plane; thirdly, the three modules are controlled to emit laser to measure the distance of the photovoltaic panel, and the coordinates of the measuring points on the photovoltaic panel are calculated according to the distance measuring result; and finally, constructing a plane equation of a plane where the photovoltaic panel is located by using the coordinates, and calculating an included angle between the plane where the photovoltaic panel is located and the xy plane. The problem that in the prior art, a user needs to climb a photovoltaic support to measure the inclination angle of a photovoltaic panel, and measurement is difficult is solved.

Provided is a 3D model reconstruction method for a weld, by converting multiple sets of two-dimensional scanning results into three-dimensional point cloud data of the weld in a welding gun coordinate system, and then extracting a spatial plane model according to the scanning weld data characteristics, and reconstructing a spatial data set matching the welding plane, the measurement error caused by the inconsistency between the measurement plane and the welding plane is solved, so as to obtain accurate weld appearance characteristics, solve the problem that the traditional method cannot truly reflect the specific change characteristics of the weld, improve the weld model precision and quality, accurately position the appearance characteristics and position of the weld, and thus improve the welding quality and precision.

A system (1) for determining the radiation characteristics of an antenna includes an azimuthal positioner (50) comprising a device for rotating an antenna (2) about a vertical axis of rotation (R), a measuring arm (10) having a free end (12) and a mounting end (11), a frame (20) on which the measuring arm is mounted and comprising means for driving the mounting end of the measuring arm in a tangential plane (P1) to a cylinder of revolution with axis, the vertical axis of rotation (R), and measuring probes (40) positioned on the free end of the arm, the measuring arm extending longitudinally towards the azimuthal positioner in a horizontal direction perpendicular to the tangential plane,the drive means of the mounting end of the measuring arm driving the entire set of measuring probes in a measuring plane (P2) parallel to the tangential plane and extending at a distance from the vertical axis of rotation. Figure for the abbreviation: [Fig.1] ,

The invention discloses a molecular marker tracing sequence multi-stripe single-frame high-speed flow field velocity measurement method, and belongs to the field of wind tunnel flow field detection. The problem of engineering requirements of high-speed flow measurement is solved. A femtosecond laser system is built in a measurement flow field; time sequence control is set for the femtosecond laser system; carrying out system calibration; image background removal processing is carried out, and then a fluorescence image converted to a standard measurement plane is obtained based on the transformation relation; carrying out fine extraction on a fluorescence signal feature region to obtain the fluorescence signal feature region; carrying out fluorescence position extraction, and extracting central point positions on a plurality of fluorescence lines; and calculating the horizontal direction speed and the vertical direction speed of the current flow field. The method provides accurate speed measurement data, is suitable for accurate measurement of a high-speed flow field, and provides powerful support for pneumatic testing and aircraft design.

The application discloses a kind of floating offshore solar radiation measurement data correction method and system, it includes the following steps: obtaining the pitch angle and roll angle of floating offshore solar radiation measurement system;Obtain the unit normal vector of the measuring plane pointing to the sky in the horizontal plane rectangular coordinate system;Calculate the angle between the measuring plane and the horizontal plane;Get horizontal plane solar zenith angle and azimuth angle;Construct the unit vector along the direction of sunlight incidence pointing to the sun;Correct the zenith angle;Calculate the horizontal plane scattered irradiance value;The horizontal plane total irradiance saved by floating offshore solar radiation measurement system is corrected, and the corrected horizontal plane total irradiance is obtained.The measurement data of the floating offshore solar radiation measurement system is corrected by the application, the measurement error caused by the inclination of the measurement platform caused by wind and wave is reduced, and more accurate measurement data is provided for the evaluation of offshore light resources and the planning of offshore photovoltaic power station.

An imaging-based non-contact gloss measurement device, includes: a housing having a top cover provided with a measurement window, a measurement zone being located above the measurement window; an illumination light source mounted inside the housing and on one side of the measurement window and configured to illuminate the measurement zone at an incident angle θ1; and a grayscale camera mounted inside the housing and on the other side of the measurement window and configured to receive light reflected from the measurement zone at a reflection angle θ2 for grayscale imaging, and obtaining gloss values from the grayscale values. The illumination light source has an incident divergence angleα1′in the measurement plane and an incident divergence angleβ1′perpendicular to the measurement plane; the grayscale camera has a reflection divergence angleα2′in the measurement plane and a reflection divergence angleβ2′perpendicular to the measurement plane, θ1=θ2,a1′>α2′⁢ and⁢ β1′>β2′.

An electronic measuring device includes a weighing plate, extending along a measuring plane and including an upper face configured to receive a user's feet; a lower face, opposite the upper face, and a rounded edge connecting the upper face to the lower face; and at least one electrode extending on the weighing plate from the upper face over the rounded edge to the lower face.

The utility model relates to the technical field of medical instruments, and discloses a haemorrhoids measurer, which comprises a handle, measuring arms and a connecting shaft, one end of the handle is connected with the connecting shaft, the periphery of the connecting shaft is connected with N groups of measuring arms in a circumferential array mode, the N groups of measuring arms are respectively vertical to the handle and are located on the same measuring plane, and the N groups of measuring arms are perpendicular to the handle. The N sub-regions are used for equally dividing the measuring plane into N sub-regions and observing the size of the occupied range of haemorrhoids in the sub-regions; wherein N is a positive integer, and N is greater than or equal to 2; a sliding groove is formed in the connecting shaft, one end of the measuring arm is arranged in the sliding groove, and the measuring arm rotates around the connecting shaft to adjust the angle of the haemorrhoids measuring arm. The size and the range occupied by haemorrhoids in the rectum can be measured through the measuring arm, and compared with traditional subjective visual diagnosis, the diagnosis accuracy is improved.

The application provides a kind of robot-based cooperative target six-dimensional pose full-automatic positioning method and system, comprising: establishing hand-eye coordinate relationship step: through the switching of tool coordinate system and vision sensor coordinate system, the hand-eye coordinate relationship of robot is established;Leveling step: the plane normal is measured and adjusted by cooperative target plane normal measurement device;Wherein, the measurement and adjustment process is a full-automatic process;Establishing initial workpiece coordinate system step: the initial workpiece coordinate system of cooperative target is established by using cooperative target plane normal measurement device;Adjustment step: adjust the posture and position of vision sensor photographing;Photographing step: photographing is carried out by using the vision sensor after the adjustment step, and the surface workpiece coordinate system of cooperative target is calculated;Positioning step: the surface workpiece coordinate system of cooperative target is established according to the photographing result, and the full-automatic positioning of cooperative target six-dimensional pose is completed.The application can be fully automatically operated, the result is accurate, the efficiency is high, and the operation is simple.

The application provides a kind of terahertz wave power distribution measurement method based on circular sensor, belong to engineering and physical experiment measurement technical field, this method includes: obtaining the quantitative relationship of the output total power of circular sensor and the power density of measurement plane;Establish the resolution of the measured power distribution image of measurement plane, the constraint condition of measurement back-propagation error and the translation step of sensor;According to the translation step control of sensor, the translation measurement of circular sensor in measurement plane is carried out, to obtain the measurement power data set;According to the resolution, the measurement plane is discretized and the objective function is constructed, and the discrete power density of the measurement plane is obtained by solving the objective function;The measured power distribution image of measurement plane is reconstructed, and the measured power distribution image of measurement plane is output.The application has the advantages of high precision, adjustable resolution and controllable error, and is suitable for high-precision measurement scenarios of various engineering and physical experiments.

A method for checking dimensions and geometrical features of a mechanical part using an optoelectronic system of the shadow casting type includes calculating the spatial coordinates of points of the surface of the part that allow a 3D reconstruction of the surface of the part, and checking the dimensions and geometrical features making use of such spatial coordinates. The spatial coordinates of the points are calculated starting from two-dimensional images and relevant profiles obtained by means of the shadow casting system while the mechanical part rotates about a rotation axis. The position of points or edges of the profiles and variation of such position are detected at predetermined heights as the rotation angle varies. On the basis of such variation, the position, with respect to a measurement plane, of points on the part to be checked which generate points of the aforementioned profile is identified and the spatial coordinates of the points of the surface are calculated.

The invention relates to a wall surface pressure measuring device and method.The device comprises a circular metal substrate, a piezoelectric chip is installed in the metal substrate in a sealed mode, the piezoelectric chip is connected with an external signal collecting system, and the metal substrate is of an integrated step-shaped structure and comprises a lower half step and an upper half step; a plurality of pressure leading holes are formed in the surface of the upper half step and used for conducting pressure on the surface of the upper half step to an internal piezoelectric chip, and a plurality of bolt grooves are formed in the lower half step in the circumferential direction and used for installing bolts, so that the metal substrate is fixedly attached to an auxiliary flat plate matched with a to-be-measured wall surface according to a required measurement angle. Compared with the prior art, a smaller measuring point interval can be realized, the sensors can be tightly arranged, a measuring plane is ensured to be flush with a wall surface to be measured, and pressure data of more spatial positions can be obtained by rotating and adjusting a measuring angle, so that the accuracy and the reliability of a measuring result are improved.

The application relates to the technical field of high-frequency field measurement and reconstruction, and discloses an electromagnetic exposure evaluation method and device for an ultra-near field and electronic equipment, wherein the electromagnetic exposure evaluation method comprises the following steps: collecting vector electric field data of a device under test in a measurement plane to obtain a sparse electric field matrix; performing super-resolution reconstruction on the sparse electric field matrix based on a propagation and gradient guided super-resolution generative adversarial network to obtain a reconstructed electric field with a target resolution; performing ultra-near field reverse deduction on the reconstructed electric field to obtain an initial estimated value of an ultra-near field electric field; performing end-to-end refinement on the initial estimated value based on a U-shaped convolutional neural network with a residual connection to obtain a target vector electric field of the ultra-near field; and performing electromagnetic exposure compliance evaluation on the target vector electric field to obtain an electromagnetic exposure compliance evaluation report. The application can realize higher-precision ultra-near field measurement and reconstruction, and obtain more accurate electromagnetic exposure compliance evaluation results.

The utility model discloses a plane inclination angle detection device, and belongs to the technical field of measurement. A plane inclination angle detection device comprises a box body structure, a movable supporting column is arranged on the bottom wall of the box body structure, a gravity block is arranged above the supporting column, a plurality of stress columns are arranged on the periphery of the gravity block, and gaps exist between the gravity block and the stress columns. The other ends of the multiple stress columns are connected with the side wall of the box body structure, strain gauges are installed on the surfaces of the multiple stress columns respectively, and wires extending to the outer side of the box body structure are installed on the multiple strain gauges. According to the device, through the supporting effect of the supporting rod, the heavy object keeps the freedom degree on the corner and is not interfered by force or bending moment perpendicular to the axial direction at the bottom, so that the accuracy of data measurement is ensured, the design of the gravity block enables the gravity block to apply uniform pressure to the surrounding rods, tiny pressure changes are captured through the strain gauges, and the accuracy of data measurement is ensured. And indirectly measuring the plane inclination angle.

Systems and methods for generating a digital model of a space and modifying the digital model are described. In one aspect, a system includes one or more computers and one or more storage devices storing instructions that, when executed by the one or more computers, cause the one or more computers to perform operations including: obtaining a point cloud representation of the space, the point cloud including multiple points; segmenting the point cloud into: (i) an inlier point cloud including multiple inlier points, and (ii) an outlier point cloud including multiple outlier points, where the segmenting includes: identifying, as the inlier points, the points of the point cloud that have at least a specified likelihood of being measurements of any of multiple planes of the space; and identifying, as the outlier points, all other points of the point cloud that are not identified as the inlier points; processing the inlier point cloud to generate a segmented inlier point cloud that includes, for each measured plane of the space, a respective plane point cloud representing the plane; and processing, using a neural network, the outlier point cloud to generate a segmented outlier point cloud that includes, for each of one or more objects detected in the space, a respective object point cloud representing the object.

The invention provides a process pipe assembling method based on machine vision. The method comprises the following steps: acquiring end face images of a first pipeline element and a second pipeline element through at least two industrial cameras respectively; calibrating each industrial camera, and establishing a mapping relation between a pixel coordinate and a measurement plane coordinate; under the condition that the view fields of the cameras are not overlapped, preset known displacement operation is executed, and the relative position relation between the cameras is determined and a unified coordinate system is established in combination with feature coordinate changes before and after displacement; extracting a circular ring contour of the end face image, performing circle fitting to obtain two-end circle center coordinates, and determining a rotation angle parameter based on an inner diameter radiation distance extreme value; and calculating a centering translation amount and an assembly rotation amount under the unified coordinate system, and outputting a motion control instruction to drive an execution mechanism to complete assembly. According to the technical scheme, automatic centering and angular assembly of the process pipes are achieved, and the assembly precision and efficiency are improved.

This invention discloses a measuring device and its method for use in deep cavity small planes. The device includes a ruler body, a ruler frame, a cover plate, a vernier frame, and a connecting structure. The ruler body is T-shaped, and the ruler frame is Y-shaped with an opening. The ruler body and frame are coaxially arranged, with the ruler body positioned inside the frame. The ruler body and frame are connected, and their ends are connected via the vernier frame. The vernier frame connects the ruler body and frame via the connecting structure. The ruler body and frame respectively contact the end faces of the symmetrical structures to be measured. Reading coordinates are provided on the ruler body. The axis of the measuring device is perpendicular to the plane to be measured. The first contact surface of the measuring device is pressed against the end face of the first symmetrical structure, and the first end face of the measuring device is pressed against the end face of the second symmetrical structure. After the measuring device stabilizes, the reading is taken using the reading coordinates on the ruler body to obtain the measured height difference. This invention solves the problems of previous measurements, significantly shortens the assembly cycle, and improves production efficiency.

The application discloses a transformer partial discharge ultrasonic positioning method based on step-by-step wave field extrapolation, which comprises the following steps: acquiring ultrasonic time domain signals collected by a sensor array arranged on the outer wall of a transformer oil tank; converting the ultrasonic time domain signals to a wave number-frequency domain through two-dimensional Fourier transform to obtain an initial wave field; performing step-by-step wave field extrapolation iteration layer by layer from a measurement plane to the inside of the transformer; in each step of iteration, first, a standard phase shift based on a reference sound velocity is performed in the wave number-frequency domain, and then the phase compensation related to the local sound velocity distribution is performed in the space-frequency domain to correct the wave front distortion caused by the transverse non-uniformity of the medium; integrating the wave field compensated after being extrapolated to each depth plane along the frequency dimension to synthesize a sound source energy distribution image and determine the spatial position of the partial discharge source. The application realizes sub-centimeter level positioning accuracy in the complex acoustic environment of the transformer internal winding shielding and the significant multi-path effect, and shows good spatial resolution and robustness in extreme scenes such as multi-source concurrency and complete shielding.

The invention belongs to the field of laser cleaning, and particularly relates to a laser cleaning method and a laser cleaning device. In order to clean a complex curved surface workpiece, the invention provides a laser cleaning method, a plurality of distance measuring sensors synchronously moving with a laser cleaning head are used for focusing, the distance measuring sensors are arranged on the same mounting plane in a non-collinear manner, and the distance between the distance measuring sensors and the focal plane of the laser cleaning head is L, the distance measuring sensor measures the distance l from the measuring points on the surface of the workpiece, all the measuring points are fitted in the same measuring plane, the average value l of the distance l and the included angle between the normal direction of the measuring plane and the main optical axis of the laser cleaning head are calculated, and the positions and postures of the laser cleaning head and the distance measuring sensor are adjusted in real time. And the difference value between the included angle between the measuring plane and the calibration plane and the set included angle is always less than 5 degrees, and l is greater than or equal to 0.95 L and less than or equal to 1.05 L. The included angle and the distance between the measuring plane and the focal plane are controlled to ensure that the laser cleaning head is at the optimal cleaning angle and the optimal cleaning focal length.

The invention discloses a bolt pretightening force precise control tool and method based on direct deformation measurement, and belongs to the technical field of mechanical assembly and precise measurement, and the tool comprises an elastic force measuring ring which sleeves a bolt and is located between a baffle and a main nut, the upper and lower end faces of the elastic force measuring ring are parallel reference surfaces, and the elastic force measuring ring has a preset rigidity coefficient k; the deformation measuring mechanism is installed on the elastic force measuring ring through a fixing frame, a measuring head of the deformation measuring mechanism makes contact with the measuring plane of the elastic force measuring ring, and the deformation measuring mechanism is used for measuring the compression deformation quantity delta L of the elastic force measuring ring in real time; and the locking nut is screwed on the bolt, is positioned between the elastic force measuring ring and the baffle plate, and is used for bearing and locking the tension of the bolt after the pre-tightening force reaches a target value, so that the elastic force measuring ring is unloaded. Through simple combination of the elastic force measuring ring and the dial indicator, direct measurement and real-time monitoring of the pre-tightening force can be realized, and while the control precision of the pre-tightening force is improved, the equipment cost and the operation complexity are reduced.

A deformation estimating device (60) comprises a control unit (50) that estimates a deformation occurring in a structural body (1) based on a measurement representing a deformation on a measurement plane of a surface of the structural body (1). The control unit (50) predicts deformation information, which—by means of a probability distribution—represents a deformation occurring on the measurement plane of the structural body (1) under a plurality of boundary conditions applied to the structural body (1).The control unit (50) specifies a first observation equation which represents a correlation between a first observation variable, which represents the measured value, an error of the measured value by a probability distribution, and the deformation prediction information, which serves as a first state variable, and estimates a deformation that occurs in the structural body, based on the first observation equation.

The invention relates to a method of determining an induction factor between a rotor plane (PR) and a measurement plane (PM), involving the steps of measuring the wind speed in at least two measurement planes (PM), determining the wind speed in the rotor plane (PR) from the measurements by means of a Kalman filter, and measuring the induction factor from the measurements and the wind speed in the rotor plane (PR) by means of an adaptive Kalman filter.

The invention relates to an electronic device, in particular an electronic device having an integrated structure for assessing a thermal path within the electronic device during the intended use thereof. The electronic device comprises an electronic component, optionally an element adjoining the electronic component, in particular a support substrate or a submount, and a first conductor track and a second conductor track, each of which has a first end and an opposite second end. The first and the second conductor track each extend from a measurement plane in the direction of a reference plane, and the second ends of the first and the second conductor track are conductively connected to one another on the reference plane. The measurement plane or the reference plane is situated on the upper face of the electronic component, and the measurement plane is situated at a distance from the reference plane. The first ends of the first and the second conductor track are electrically insulated from one another on the measurement plane and are designed to be able to detect, on the conductor tracks, a voltage dropping across the first and second conductor tracks. The first conductor track consists of a first electrically conductive material, and the second conductor track consists of a second electrically conductive material which differs from the first.

The utility model discloses a railway track inspection tester superelevation measuring unit adjusting device which comprises a tool clamp, supporting plates are symmetrically and fixedly connected to the two sides of the inner wall of the tool clamp, a fixed end round hole and an adjusting end long hole are formed in the surfaces of the two supporting plates respectively, the fixed end round hole is connected with an adjusting bottom plate through a butt-joint bolt, and the adjusting bottom plate is connected with the adjusting end long hole through a butt-joint bolt. The other end of the adjusting bottom plate is connected with the adjusting end long hole through a butt joint bolt, the adjusting bottom plate is provided with a horizontal inclination angle sensor through a connecting structure, the two sides of the inner wall of the tool clamp are in threaded connection with flat end adjusting screws, and the inner side ends of the flat end adjusting screws abut against the adjusting bottom plate. The adjusting device for the superelevation measuring unit of the railway track inspection tester can adjust the measuring plane of the tilt angle sensor to be perpendicular to the pushing direction of equipment, so that the phenomenon that a horizontal measured value is inaccurate due to inertia force when the equipment is pushed is eliminated.

The present invention relates to a method for generating control data for producing a circular chamfer of a defined chamfer geometry on a workpiece by machining in a machine tool, comprising the steps of: defining a measuring plane orthogonal to the main extension direction of the workpiece; defining a series of measuring points in the area of ​​the circular chamfer to be produced, wherein the intersection of the cutting edge adjacent to the circular chamfer to be produced with the measuring plane is defined as the reference point for the series of measuring points; removing material from the workpiece; determining a height profile of the workpiece surface in the area of ​​the circular chamfer to be produced; comparing the determined height profile with the chamfer geometry to be produced; and adjusting the defined control data for producing the circular chamfer depending on the determined result of the comparison.Optional repetition of material removal, determining the height profile, and comparing the height profile with the chamfer geometry to be produced.

The invention relates to the field of optical measurement devices, in particular to displacement sensors, 3D sensors for measuring the position and / or shape or thickness of a measurement object or roughness sensors for measuring the roughness of the surface of an object. Measurement light is projected onto a measurement object after filtering by a first Fabry-Perot filter such that at each point in a measurement plane, the filtered measurement light has a locally unique wavelength or combination of wavelengths in at least one direction in the measurement plane. Measurement light reflected from the surface of the measurement object is filtered by a second Fabry-Perot filter in order to filter out measurement light not reflected from the intersection of the measurement object with the measurement plane.