Image Measurement Method Research Articles

The physical and mechanical properties for flexible biomass particles using computer vision

The combustion and fluidization behavior of biomass depend on the physical properties (size, morphology, and density) and mechanical performances (elastic modulus, Poisson's ratio, tensile strength and failure strain), but their quantitative models have rarely been focused in previous researchers. Hence, a static image measurement for particle physical properties is studied. Combining the uniaxial tension and digital image correlation technology, the dynamic image measurement method for the mechanical properties is proposed. The results indicate that the average roundness, rectangularity, and sphericity of present biomass particles are 0.2, 0.4, and 0.16, respectively. The equivalent diameter and density obey the skewed normal distribution. The tensile strength and failure stress are sensitive to stretching rate, fiber size and orientation. The distribution intervals of elastic modulus and Poisson's ratio are 30–600 MPa and 0.25–0.307, respectively. The stress–strain curves obtained from imaging experiments agree well with the result of finite element method. This study provides the operating parameters for the numerical simulation of particles in the fluidized bed and combustor. Furthermore, the computer vision measurement method can be extended to the investigations of fossil fuels.

Case analysis of thermal defect detection of near-zero energy building envelope based on infrared thermography

The thermal performance of the envelope structure is one of the important components of the performance design of near-zero energy buildings. Minimizing envelope heat loss is the key to improving building energy efficiency. A necessary first step in the building envelope optimization process is the assessment of its actual thermal performance. This paper summarizes the application status of infrared thermography in thermal defect detection of building envelopes and common forms of thermal defects in near-zero energy buildings. Taking a near zero energy building in Shenyang area as the target object, an efficient and non-destructive infrared thermal image measurement method is applied to determine the thermal defect rating of the building from both qualitative and quantitative aspects. The results show that the building has high thermal performance. The temperature field distribution of the building envelope could be quickly obtained by using the infrared thermal imaging instrument. In this way, it can accurately identify the location of thermal bridges and air tightness defects, and provide an efficient and accurate detection method for building energy-saving diagnosis and evaluation.

Experimental study on flow properties of coal ash slag based on the image measurement method

AbstractThis paper aims to reveal the effect of adding biomass ash on the flow characteristics of Zhundong (ZD) coal ash. A new visual image measurement method for the flowability of coal ash was established. Furthermore, scanning electron microscopy (SEM) and x‐ray diffraction (XRD) were applied to analyze the influence of surface morphology and mineral component on the fusion fluidity of the samples. The results show that the flow properties of ZD ash are improved to varying degrees after adding maize straw (MS) ash. As the blending ratio increases, the improvement of flow velocity is higher. The critical flow temperature (TC) of the samples was calculated. The TC of ZD ash was 1249°C, which decreased with the addition of MS ash. The characterization results showed that adding MS ash increased the melting phase, while the surface of the samples tended to be dense and smooth. Meanwhile, the massive formation of hauyne with a low melting point and the high proportion of SiO2/Al2O3 in the ash promotes the melting behavior of the ash slag. The flow velocity of the samples is improved under the combined action of the increase of the melting phase and the smooth surface.

Terminal velocity and drag coefficient models for disc-shaped particles based on the imaging experiment

Terminal velocity and drag coefficient are the core parameters of particle motion, but their predictive models and measuring methods have rarely been focused. In this work, terminal velocity and drag coefficient models for disc-shaped particles are proposed based on the imaging experiment. Experimental devices include particle sedimentation and video image acquisition systems. A total of 120 disc-shaped particles sedimentation are investigated. Results show that terminal velocity closely relates to the shape, size and density of the particles. Thus, particle shape factors should be considered in the drag coefficient model. The proposed models fitted by the LM + UGO optimization algorithm, have more accuracy and stability than the published models. The present study is applicable for the disc-shaped particles in the ranges of sphericity φ = 0.56–0.77, flatness ratio da /dv = 0.65–1.21, circularity ψ = 0.59–1, and Reynolds number Re = 323–10,800. Furthermore, the imaging measurement method can be extended to other non-spherical particles.

Analysis of plume–lunar surface interaction and soil erosion during the Chang’E-4 landing process

When the lander approaches the lunar surface, the rocket exhaust will erode the surface and eject massive high-speed dust, which could damage the payloads on the lander or interfere with subsequent surface operations. This process also provides a unique opportunity to study the plume–dust interaction and the wind erosion on the surface of airless body such as the Moon. Previously, limited knowledge was obtained from Apollo landing images and a simplified erosion model is built to study the erosion process. With high-quality data acquired in the landing process of Chang’E-4 (CE-4) mission, for the first time, we aim to quantify the dust ejection angle and erosion depth for a low-thrust lander, test the effectiveness of the current erosion model, and provide reference information for future landing missions. We use image measurement methods to extract key parameters such as dust ejection angle and erosion depth from the landing image of CE-4. For comparison with the observation, we also employ an erosion model to estimate the erosion thickness. The dust appears at about 7 s before the lander touch the surface, with a height of 13 m above the surface. When the nozzle altitude was about 0.6 m, the dust ejection angle is measured to be above 7°, while the dust ejection angle calculated by the particle trajectory method is less than 4.3°for particle sizes smaller than 1 mm. For the first time, an average erosion depth of 0.7 cm is measured between 1.12 m and 2 m from the nozzle centerline for a low-thrust lander. The measurement corresponds to an erosion time duration from 1.1 s before landing to 0.4 s after landing. The measured erosion range using CE-4 data is much larger than the estimated erosion radius given by the previous erosion model. It indicates that the dust’s angular distribution, local topography of the landing area, and other factors are important in improving the precision of the erosion model.

Compound-eye imaging imitation-based whole-field flow measurement

Large-scale particle image velocimetry (LSPIV) has been increasingly applied in whole-field flow measurement for its non-contact operation mode. However, due to the complicated flow conditions and optical disturbances on the water-air interface, commonly-used imaging technologies are degenerated by the low visibility and image distortion. There are also increased challenges for control point calibration. This paper proposes an imaging measurement method that imitates the imaging computation mechanism in compound eyes. The method is independent of ground control points and can achieve flow measurement with natural patterns, which can solve the problem caused by the lack of visible tracers. Field evaluation results demonstrate that this is the first method to achieve real-world whole-field flow measurement in challenging conditions. Specifically, the velocimetry error is less than 5%, while ranging from 5% to 15% for other LSPIV systems. The method meets current hydrological standards and acquires flow data in wild rivers, performance that is realized with difficulty by other methods.

Contactless temperature measurement in wire-based electron beam additive manufacturing Ti-6Al-4V

The complex thermal cycles and temperature distributions observed in additive manufacturing (AM) are of particular interest as these define the microstructure and the associated properties of the part being built. Due to the intrinsic, layer-by-layer material stacking performed, contact methods to measure temperature are not suitable, and contactless methods need to be considered. Contactless infrared irradiation techniques were applied by carrying out thermal imaging and point measurement methods using pyrometers to determine the spatial and temporal temperature distribution in wire-based electron beam AM. Due to the vacuum, additional challenges such as element evaporation must be overcome and additional shielding measures were taken to avoid interference with the contactless techniques. The emissivities were calibrated by thermocouple readings and geometric boundary conditions. Thermal cycles and temperature profiles were recorded during deposition; the temperature gradients are described and the associated temperature transients are derived. In the temperature range of the α+β field, the cooling rates fall within the range of 180 to 350 °C/s, and the microstructural characterisation indicates an associated expected transformation of β→α'+α with corresponding cooling rates. Fine acicular α and α’ formed and local misorientation was observed within α as a result of the temperature gradient and the formation of the α’.

Accuracy assessment of fringe projection profilometry and digital image correlation techniques for three-dimensional shape measurements

With ever-increasing demand for three-dimensional (3D) imaging and shape measurements in a variety of fields, measurement accuracy has become of vital importance to numerous scientific and engineering applications. This paper presents an experimental investigation into the accuracy comparison of two prevalent 3D imaging and shape measurement methods: fringe projection profilometry (FPP) and 3D digital image correlation (3D-DIC) techniques. A detailed description of their principles reveals their inherent similarities and fundamental differences. A measurement system composed of both techniques is employed in the study, and a test target with speckle checkerboard patterns on its surface is adopted to allow simultaneous FPP and 3D-DIC measurements. The evaluation puts emphasis on how the geometric angles between key hardware components affect the 3D measurement accuracy. Experiments show that the depth and height measurements of both techniques can reach sub-micron accuracy, and the relative accuracy of the 3D shape or position measurements can reach 1/600 000.

In-situ stress measurement technology and field application based on micro-optical imaging measurement method

In-situ stress is natural stress existing in rock masses. As an important basic parameter, accurate in-situ stress is highly beneficial to the theoretical research and engineering application of rock mechanics. In-situ tests in boreholes are the most direct and effective way to obtain in-situ stress. However, the high temperature and high water pressure testing environment in boreholes limits the application scope of measurement sensors. In this study, a micro-optical imaging measurement method is proposed. On the basis of this method, an aperture measurement device is developed, and a complete set of in-situ stress measurement technology is formed. Laboratory and field application tests are carried out. The results of the temperature and pressure test in a laboratory show that the in-situ stress test technology improves service temperature and pressure and offers an extensive application range. The field test on a shallow borehole in an iron mine roadway and a deep borehole in a shale gas exploration well reveals the deformation of the test boreholes in the process of stress relief. This result proves the feasibility of the in-situ stress measurement technology. On the basis of the theory of elasticity, in-situ stress is calculated with reference to the in-situ diameter deformation of the boreholes and the mechanical parameters of the rock core. A number of in-situ stress tests are carried out under different borehole depths, and the testing times are recorded. Results show that the application of wireline coring drilling technology speeds up the test process. Hence, it can boost the operability of the in-situ stress test. In sum, the in-situ stress measurement technology based on the micro-optical imaging measurement method is feasible and operable and may thus improve the application depth of the in-situ stress measurement method based on the stress relief method.

A Rapid Method of Monocular Image Measurement Based on Rectangle Information

A method of rapid measurement of monocular image based on rectangle information is proposed in this paper. Based on the pinhole imaging model, a fast method of calculating the object size in monocular image is derived by fitting the straight line and then finding the intersection point of the straight line. The algorithm can not only measure the size and absolute depth of the object in monocular image, but also meet the conditions of the specific pinhole imaging model with a distance far greater than the focal length. The complexity of the algorithm is low, and it can meet the requirements of real-time calculation. It provides a new idea for the use of small and micro-computing platform.

Abstract 5451: Longitudinal proteomic assessment of patient with metastatic apocrine adenocarcinoma reveals evolutionary selection for androgen-receptor-dependence and therapeutic response

Abstract Combined use of new molecular diagnostic and imaging methods could improve care of individual patients with rare cancers. A 57-year-old developed apocrine adenocarcinoma of the left axilla with regional lymph node metastasis detected at initial surgery. After adjuvant regional radiotherapy, metastases developed and over the subsequent 7 years he received serial systemic therapy with 11 different regimens. Expression of 128 proteins/phosphoproteins was evaluated in 8 tissue samples from diagnosis, progressive adenopathy at 45 months, brain metastases at 60 months, and abdominal metastases at 63 months by CLIA-standardized reverse phase phosphoprotein arrays (RPPA). Tumor burden was estimated by quantifying the volume of individual lesions with semi-automated segmentation algorithms on serially collected CT images. Next-generation sequencing (NGS) revealed a PIK3CA K111T mutation, prompting treatment with sirolimus 28 months after diagnosis. Seventeen months later, new neoplastic adenopathy emerged. NGS revealed a new PIK3CA M610V mutation. Semiquantitative scoring of RPPA demonstrated relative increase in AKT (from 0.72 to 0.9) and mTOR (from 0.55 to 0.8) pathway activation. The relative estimated tumor burden (RETB) was 21,145 mm3. Over 6 months of docetaxel therapy the RETB decreased to 12,077 mm3. The patient subsequently received pembrolizumab with increased RETB (71,308 mm3). Gemcitabine appeared to stabilize the RETB (73,168 mm3), but brain metastases emerged. The patient underwent craniotomy, began paclitaxel therapy, and then RETB declined to 35,623 mm3. But new symptomatic abdominal metastases prompted surgical resection. The patient then received the PI3K inhibitor taselisib; however, after an initial decrease, RETB rose to 31,208 mm3. At this point, the patient began bicalutamide therapy. NGS of the primary mass and the initial metastatic adenopathy revealed no amplification of the androgen receptor (AR). But RPPA demonstrated inversion of the ratio of measured phosphorylated AR S81 to AR S650, suggesting primarily cytoplasmic AR in tumor through 45 months but nuclear AR in samples resected at 60 and 63 months. Immunohistochemistry revealed 3+ nuclear AR expression in the latter metastatic tissue. After 9 months of bicalutamide, enzalutamide and leuprolide were administered for 7 months (final RETB = 1,555 mm3). Treatment continued beyond the study period. Tumor burden assessment by new CT imaging measurement methods, combined with RPPA could improve adaptive, responsive, therapy for patients with rare tumors. We identified the phenotypic evolution of androgen-driven growth of apocrine adenocarcinoma after cytotoxic and PI3K-mTOR inhibitor therapy. Protein-based diagnostics revealed an effective treatment strategy in late metastatic disease that was not indicated by NGS testing. Citation Format: Erik Dvergsten, Anthony Serritella, Danielle Kimble, Malcom McIver, Sanja Karovic, Vasiliki Thomeas-McEwing, Hao Yang, Manish R. Sharma, Thomas P. Conrads, Mariaelena Pierobon, Peter Pytel, Binsheng Zhao, Lawrence H. Schwartz, Emanuel F. Petricoin, Russell Szmulewitz, Michael L. Maitland. Longitudinal proteomic assessment of patient with metastatic apocrine adenocarcinoma reveals evolutionary selection for androgen-receptor-dependence and therapeutic response [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5451.

The management of error in ultrasound fetal growth monitoring.

It is important to understand the uncertainty in fetal measurements when using them in the management of pregnancy. The aim of this essay is to provide background on errors and uncertainty, describing error sources and their potential impact, with guidance on improving accuracy. Errors can be systematic or random, arising from equipment, image plane selection, measurement method and caliper placement and influenced by image quality, training and experience. The uncertainty in measurements is larger than clinically significant differences in fetal size and growth. Errors can be reduced by implementing equipment acceptance testing, written procedures, training and audit.

Direct surface area measurement from digital images via brightness histogram method

A direct, shape- and scale-independent digital image measurement method of the surface area (SA) of individual objects is proposed. The algorithms presented herein utilize the brightness histogram of 8-bit greyscale images, and thus are referred to as a brightness histogram surface area measurement algorithm (BHSAMA). The proposed SA measurement technique allows the uncertainty of the single measurement reading to be evaluated by traditional error propagation. Furthermore, the numerical value of the propagated uncertainty reflects the pixel brightness gradient of the edge pixels. This fact alone presents a significant advantage to the current methods utilizing image segmentation and/or edge detection whose measurement uncertainties cannot be quantitatively analysed. The proposed method does not involve any shape-related approximations. Five examples illustrating the method are discussed. For method verification purposes, a series of digital simulations using a control sample of predetermined size is undertaken. The accuracy of the single measured SA reading is between 0.5% and 1.5%. The uncertainty of the measured SA is evaluated and discussed further as a function of two types of simulated blurred edge region. The two presented BHSAMA techniques can have a wide range of applicability, from nanoparticles to cell biology to aerial imagery.

Measurement of the useful field of view for single slices of different imaging modalities and targets.

Purpose: With three-dimensional (3-D) images displayed as stacks of 2-D images, radiologists rely more heavily on vision away from their fixation point to visually process information, guide eye movements, and detect abnormalities. Thus the ability to detect targets away from the fixation point, commonly characterized as the useful field of view (UFOV), becomes critical for these 3-D imaging modalities. We investigate how the UFOV, defined as the eccentricity, in which detection performance degrades to a given probability, varies across imaging modalities and targets. Approach: We measure the detectability of different targets at various distances from gaze locations for single slices of liver computed tomography (CT), 2-D digital mammograms (DM), and single slices of digital breast tomosynthesis (DBT) cases. Observers with varying expertise were instructed to maintain their gaze at a point while a short display of the image was flashed and an eye tracker verified observer's steady fixation. Display times were 200 and 1000ms for CT images and 500ms for DM and DBT images. Results: We find variations in the UFOV from 9 to 12deg for liver CT to as small as 2.5 to 5deg for calcification clusters in breast images (DM and DBT). We compare our results to those reported in the literature for lung nodules and discuss the differences across methods used to measure the UFOV, their dependence on case selection/task difficulty, viewing conditions, and observer expertise. We propose a complementary measure defined in terms of performance degradation relative to the peak foveal performance (relative-UFOV) to circumvent UFOV's variations with case selection/task difficulty. Conclusion: Our results highlight the variations in the UFOV across imaging modalities, target types, observer expertise, and measurement methods and suggest an additional relative-UFOV measure to more thoroughly characterize the detection performance away from point of fixation.

Quick measurement of all filaments' diameters in E-glass yarn by Image-Pro Plus

At present, there are many methods to measure the diameters of filaments in E-glass yarn, but only the average diameter is reported, which cannot reflect all the filaments in the yarn. The methods based on physical principle are not intuitive, the data based on the longitudinal fiber diameter image measurement method are not comprehensive, the observation on the cross-section image of yarn based on slice-making is time-consuming and labor-intensive, and requires manual measurement or self-developed software application. In this article, Keyence VK-X110 3D laser morphometry microscope was used to quickly obtain the cross-section image of glass filament yarn without making a slice of E-glass yarn, and Image-Pro Plus was used to measure all the filaments' diameters in the yarn automatically. The measurement data and analysis show that under the condition of completely processing all the filaments' image, minor axis of filament cross-section is approximate to the filament diameter. This method is not only able to verify whether glass filament yarn meets the quality criteria of ASTM D578-00, but also provides the diameter distribution of all the filaments in an E-glass yarn. In addition, the data support more comprehensive evaluation standard for the quality of glass filament spinning.

Does Bone Loss Imaging Modality, Measurement Methodology, and Interobserver Reliability Alter Treatment in Glenohumeral Instability?

To determine, in the context of measuring bone loss in shoulder instability, whether measurement differences between magnetic resonance imaging (MRI) and computed tomography (CT), linear-based and area-based methods, and observers altered the proposed treatment when a standardized algorithm was applied. This was a retrospective, comparative imaging study of preoperative patients with anterior shoulder instability with both an MRI and CT scan within 1year of one another. On parasagittal images reoriented en face to the glenoid, 2 attending orthopaedic surgeons measured glenoid width, glenoid area, glenoid defect width, and glenoid defect area. On axial images maximal Hill-Sachs width was measured. From these, linear percent glenoid bone loss (%GBL) and area %GBL were calculated, and on-versus off-track was determined. With these results, a recommended treatment was determined by applying a standardized algorithm, in which the Latarjet procedure was selected for %GBL >20%, arthroscopic labral repair and remplissage for off-track lesions with %GBL <20%, and arthroscopic labral repair on-track shoulders with %GBL <20%. In total, 53 patients with mean ± standard deviation 45 ± 83days between scans were include with a CT linear %GBL of 23.5 ± 9.6% (range 0%-47%). CT lead to larger measurements of %GBL than MRI (linear P= .008, area P=.003), and fewer shoulders being considered on-track (33.0% vs 40.5%), which would alter treatment in 25% to 34%. Linear measurements produced larger values for %GBL (CT, P < .001; MRI, P < .001), which would alter treatment in 25%. For %GBL, inter-rater reliability was good, with intraclass correlation coefficients varying from 0.727 to 0.832 and Kappa varying from 0.57 to 0.62, but these inter-rater differences would alter treatment in 31%. The significant differences in bone loss measurement between imaging modality, measurement method, and observers may lead to differences in treatment in up to 34% of cases. Linear CT measurements resulted in the most aggressive treatment recommendations. Retrospective Comparative Study: Diagnostic, Level III.

Micro-vision image measurement for spot arrays on silicon wafer ablated by femtosecond laser

When using femtosecond laser micromachining center to ablate spot array on silicon wafers, it is difficult to measure the spot spacing directly by physical method because of the small geometric size between the spots. In order to quickly acquire the geometric dimensions between the spot arrays, the micro vision image measurement method is used to measure the distance of spot arrays, and a high precision measurement result is obtained. In the experiment, femtosecond laser power with 20 mW was used to ablate the spot on the surface of silicon wafer and visual measurement for the obtained spot array is realized. Firstly, a telecentric micro-vision system with a field of view of 2.528 × 1.896 mm is constructed to realize image acquisition of spot arrays. Secondly, the micro-vision system is calibrated by using the geometrical optical resolution plate, and the measurement ratio constant Kw is obtained; in the meantime, in order to improve the calibration accuracy, the resolution plate image was processed by vertical correction and pseudo-color enhancement, and the separation lines between the line pairs were extracted by Hough transform. Thirdly, in order to accurately extract the geometric center of the spot image and improve the measurement accuracy of the spacing between the spot, the R-component partitioning image of spot array is analyzed; its three-dimensional image presents a complete stereoscopic morphology of spot, which can be used as an input image for image measurement. Finally, the spot arrays were measured by image measurement method and compared with the size measured under a microscope. The results show that the maximum measurement error of micro vision measurement method is 3%, which meets the requirement of measurement accuracy.

Mover Position Detection for PMSLM Based on Line-Scanning Fence Pattern and Subpixel Polynomial Fitting Algorithm

The article presents a rapid and precision position detection method for permanent magnet synchronous linear motors (PMSLM) based on digital image measurement and line-scanning photography. An exclusive fence pattern is designed as the target image for image measurement method, according to the motion feature of PMSLM. A line scan camera is installed on the mover to record image sequences instantaneously with the movement of linear motor, and from which the pixel displacement can be obtained using an image matching algorithm. To further improve the measurement accuracy, a subpixel polynomial fitting algorithm is proposed based on the line-scanning fence patterns. Finally, the displacement can be calculated according to system magnification parameters. Compared with the traditional image measurement method based on the area-array speckle pattern, both the cost and time delay of the proposed method are reduced greatly by employing line-scanning photography. The detection accuracy is also improved by four times. To improve the measurement robustness, an assessment index of fence pattern is proposed to optimize the fence image. The measurement error and robustness are analyzed in theory and simulation, and it demonstrates that the fence pattern shows stronger resistance to scanning deviation than speckle pattern. A mover position detection platform is established, and the experimental results show that the proposed method can achieve position estimation with average error of 0.005 mm under different working conditions.

Research on Crack Propagation Law of Assembly Concrete Structure in Hydraulic Engineering Based on Large Data Analysis

In order to grasp the law of crack propagation in concrete structure, the research on the law of crack propagation in assembly concrete structure of hydraulic engineering based on large data analysis is put forward. The mechanical parameters in the process of concrete structure fracture are obtained by digital image measurement method, and the loss difference is calculated. According to the calculation results, the fracture orientation change is judged, and the law of concrete fracture orientation change is concluded, thus the law of crack propagation in assembled concrete structure is deduced. At last, the experiment proves that the research on crack propagation law of assembly concrete structure in hydraulic engineering based on large data analysis has high accuracy and practicability, and fully meets the research requirements.

An Accurate Image Measurement Method Based on a Laser-Based Virtual Scale.

Image measurement methods have been widely used in broad areas due to their accuracy and efficiency. However, current techniques usually involve complex calibration, an elaborate optical design, or sensitivity to the test environment. In this paper, a simple optical device was designed to emit parallel beams to obtain a virtual scale for measurement purposes. The proposed theory ensures the robustness of the system when obtaining each scale in the presence of uncertainty. The scale creates a mapping from image coordinates to world coordinates. By using the moving least squares (MLS) method, a full-field scale map can be reconstructed to achieve high-precision measurement at the sub-pixel level. Experimental verifications are carried out, showing that the proposed method provides very accurate and reliable results. The proposed approach is simple in terms of equipment, and the scale can be automatically calculated. Therefore, the system proposed in this paper is a promising candidate as a tool for non-contacting measurements (e.g., the crack development, geometric size) in the inaccessible structures such as high-rise buildings and long-span bridges.