Three-dimensional Imaging System Research Articles

POSSIBILITIES OF THE APPLICATION OF THREE-DIMENSIONAL TECHNOLOGIES AND MODERN TECHNOLOGICAL MEANS IN THE CRIME INVESTIGATION ACTIVITY

The issues related to the introduction of innovative methods, technologies and technological means in the investigation of crimes are considered. It is noted that one of the main directions of the development of Criminalistics is the assimilation of the virtual reality associated with computerization of spheres of life, implementation of modern technologies and their use in law enforcement. Technology use of laser scanning of terrain and objects resulting in 3D model is produced allows several times to increase informative value of data collected at the incident scene, provides a visual and convenient visualization in three-dimensional form. As against photo and video images, 3D model has a stereoscopic image and the ability to freely change the angle while viewing. Besides to scanning results can be stored on any digital media without the possibility of changes or adjustments. Attention is focused on the technological capabilities of 3D-visualization systems on examples of their use in foreign countries as technological means of capturing the situation of the scene and the subsequent of a crime reconstruction. Thus, using a portable three-dimensional imaging system for working with volumetric traces at a crime scene, it is possible to obtain accurate three-dimensional images of traces of protectors or footprints (shoes) on soil and snow. This system is an alternative to traditional methods of fixing evidence: photofixing and making plaster casts. Unlike other systems, new approach does not require the use of lasers. The expediency of expanding the range of 3D laser scanning system use in modern investigative and judicial practice of our state with the aim of increasing the level of provision of pre-trial investigation authorities with technological means and bringing it closer to European standards is argued.

Novel three-dimensional imaging system may facilitate gastric endoscopic submucosal dissection procedure: an ex vivo animal study.

Background and study aims Endoscopic submucosal dissection (ESD) requires advanced skills to perform safely without complications. The current study evaluated the usefulness of a novel three-dimensional (3D) imaging system in ESD using porcine stomachs. Methods Four endoscopists (two trainees and two experts) performed eight ESD procedures using both 3D and 2D images. The usefulness of 3D image versus 2D image was evaluated by visibility and procedure time. In addition, occurrence of eyestrain and dizziness in 3D image was assessed. Results En bloc resection was successfully achieved, without perforation, in all cases. The evaluation score in the 3D image group was better than that in the 2D image group, particularly depth perception was statistically significantly good. No significant difference was found in the working speed between the 2D and 3D image groups. Two examiners experienced eyestrain and dizziness while using the 3D image. Conclusions All the ESD procedures were performed safely. Depth perception using the 3D image was better than with the 2D image. A novel 3D image system may facilitate ESD.

Design and modeling of pulsed-laser three-dimensional imaging system inspired by compound and human hybrid eye

A pulsed-laser three-dimensional imaging system inspired by compound and human hybrid eye is proposed. A diffractive optical element is used to enlarge field of view (FOV) of transmitting system and a receiving system consisting of a non-uniform microlens array, an aperture array, and an avalanche photodiode array is designed. The non-uniform microlens array is arranged on a curved surface to mimic large FOV feature of the compound eye. Meanwhile, the non-uniform microlens array is modeled to mimic space-variant resolution property of the human eye. On the basis of the proposed system, some simulation experiments are carried out. Results show that the entire FOV is up to 52°, and the resolution is 30 × 18. The proposed system has a high resolution in the center FOV and a low resolution in the peripheral FOV. The rotation and scaling invariances of the human eye are verified on the proposed system. The signal-to-noise ratio (SNR) increases with the increase in the number of rings and the maximum SNR locates at the outmost periphery area. This work is beneficial to the design of the pulsed laser three-dimensional imaging system with large FOV, high speed, and high resolution.

Novel pH-sensitive zinc phthalocyanine assembled with albumin for tumor targeting and treatment.

PurposeZinc phthalocyanine (ZnPc) has been applied widely in photodynamic therapy (PDT) with high ROS-production capacity and intense absorption in the near-infrared region. However, weak tumor targeting and the aggregation tendency of ZnPc seriously affect the therapeutic effect of PDT. Therefore, overcoming the aggregation of ZnPc and enhancing its antitumor effect were the purpose of this study.MethodsIn this study, we first found that the aggregation behaviors of the photosensitizer ZnPc(TAP)4, ZnPc substituted by tertiary amine groups, were regulated finely by pH and that ZnPc(TAP)4 could be disaggregated gradually as the pH descended. ZnPc(TAP)4 and human serum albumin (HSA) molecules were assembled into nanoparticles (NPs) for tumor targeting. Meanwhile, the chemotherapy drug paclitaxel (Ptx) was loaded into HSA NPs together with ZnPc(TAP)4 for dual antitumor effects. HSA NPs loading both ZnPc(TAP)4 and Ptx (NP–ZnPc[TAP]4–Ptx) were characterized by particle size and in vitro release. Cytotoxicity, subcellular localization, tumor targeting, and anticancer effect in vivo were investigated respectively.ResultsWe found that NP–ZnPc(TAP)4–Ptx had good stability with qualifying particle size. Interestingly, ZnPc(TAP)4 was released from the NPs and the photodynamic activity enhanced in the acidic environment of tumor. In addition, NP–ZnPc(TAP)4–Ptx had prominent cytotoxicity and time-dependent subcellular localization characteristics. Through a three-dimensional animal imaging system, NP–ZnPc(TAP)4–Ptx showed much-enhanced tumor targeting in tumor-bearing mice. Above all, NP–ZnPc(TAP)4–Ptx was demonstrated to have the synergistic anticancer effect of PDT and chemotherapy.ConclusionNP–ZnPc(TAP)4–Ptx had enhanced tumor targeting for the pH-sensitive property of ZnPc(TAP)4 and the transport function of HSA. NP–ZnPc(TAP)4–Ptx possessed a double-anticancer effect through the combination of ZnPc(TAP)4 and Ptx. This drug-delivery system may also be used to carry chemotherapy drugs other than Ptx for improving antitumor effects.

Wavelength-time coding for multispectral 3D imaging using single-photon LiDAR.

Single-photon multispectral light detection and ranging (LiDAR) approaches have emerged as a route to color reconstruction and enhanced target identification in photon-starved imaging scenarios. In this paper, we present a three-dimensional imaging system based on a time-of-flight approach which is capable of simultaneous multispectral measurements using only one single-photon detector. Unlike other techniques, this approach does not require a wavelength router in the receiver channel. By observing multiple wavelengths at each spatial location, or per pixel (four discrete visible wavelengths are used in this work), we can obtain a single waveform with wavelength-to-time mapped peaks. The time-mapped peaks are created by the known chromatic group delay dispersion in the laser source's optical fiber, resulting in temporal separations between these peaks being in the region of 200 to 1000 ps, in this case. A multispectral single waveform algorithm was proposed to fit these multiple peaked LiDAR waveforms, and then reconstruct the color (spectral response) and depth profiles for the entire image. To the best of our knowledge, this is the first dedicated computational method operating in the photon-starved regime capable of discriminating multiple peaks associated with different wavelengths in a single pixel waveform and reconstructing spectral responses and depth.

Three-dimensional imaging system with both improved lateral resolution and depth of field considering non-uniform system parameters.

In this paper, we propose a new 3D passive image sensing and visualization technique to improve lateral resolution and depth of field (DoF) of integral imaging simultaneously. There is a resolution trade-off between lateral resolution and DoF in integral imaging. To overcome this issue, a large aperture and a small aperture can be used to record the elemental images to reduce the diffraction effect and extend the DoF, respectively. Therefore, in this paper, we utilize these two pickup concepts with a non-uniform camera array. To show the feasibility of our proposed method, we implement an optical experiment. For comparison in details, we calculate the peak signal-to-noise ratio (PSNR) as the performance metric.

Canopy structure affects temperature distributions and free convection in moss shoot systems.

Nonvascular plants play important roles in exchange of water and heat at the soil-atmosphere interface. Differential evaporative cooling may cause temperature gradients within bryophyte canopies, influencing convective heat and mass transport. Understanding mechanisms that affect fluxes through moss layers should improve models of forest floor function. A three-dimensional thermal imaging system measured temperature distributions within moss shoot systems that were used to explore relationships among canopy structure, temperature gradients, evaporation, and conductance to water vapor (gs ). We studied five moss species under dark and light conditions in the lab. Also, these properties were measured in two species that differed in canopy structure during drying. Differential evaporative cooling led to a 1.4 to 5.0°C range in shoot temperatures within canopies. Samples displayed -0.5 to -0.9°C/cm temperature gradients with cooler apical temperatures. Gradient magnitudes did not differ among species, but taller canopies expressed greater temperature differences. Light enhanced both the gradient and the temperature difference. Rates of evaporation were significantly related to canopy height in the light, but not in the dark, although gs was positively associated with canopy height in both. Rayleigh (Ra) numbers characterize whether temperature gradients likely generate free convection. In tall canopies, Ra numbers exceeded the value indicative of free convection and turbulent flow. As plants dried, temperature gradients decreased. When moss canopies are wet, cooler apical temperatures create thermal instabilities within the canopies that appear sufficient to enhance convective transport of water vapor and heat in tall canopies with low bulk density.

Autofocusing algorithm for a digital holographic imaging system using convolutional neural networks

Digital holographic imaging systems are promising three-dimensional imaging systems that acquire holograms via interference of a reference wave and an object wave. Using digital holography and the numerical diffraction theory, an image can be reconstructed at any distance from the hologram. However, accurate determination of the distance of the object from the hologram is required to focus the image. Various autofocusing algorithms have been studied. The conventional autofocusing algorithm creates the focused image by evaluating iteratively reconstructed images using focus metrics. Owing to the iterative image reconstruction process, the computational time is very long. In this paper, an autofocusing algorithm for a digital holographic imaging system using convolutional neural networks, similar to pattern recognition systems, is proposed. Using the proposed method, the distance of the object from the hologram is obtained more rapidly than using the conventional method.

Concept to Commercialization of an Artifact for Evaluating Three-Dimensional Imaging Systems per ASTM E3125-17.

The relative-range error test is one of several tests described in the ASTM E3125-2017 standard for performance evaluation of spherical coordinate three-dimensional (3D) imaging systems such as terrestrial laser scanners (TLS). We designed a new artifact, called the plate-sphere target, that allows the realization of the relative-range error tests quickly and efficiently without the need for alignment at each position of the test.Use of a simple planar/plate target requires careful alignment of the target at each position of the relative-range error test, which is labor-intensive and time-consuming. This new artifact significantly reduces the time required to perform the test, from a matter of about 2 h to less than 30 min while resulting in similar test uncertainty values.The plate-sphere target was conceived and initially developed at the National Institute of Standards and Technology (NIST), improved based on feedback from collaborators at the National Research Council (NRC) of Canada and TLS manufacturers, and commercialized by Bal-tec Inc.This new artifact will save users and manufacturers of TLSs considerable time and money.

Validation of the Vectra XT three-dimensional imaging system for measuring breast volume and symmetry following oncological reconstruction

PurposeThree-dimensional surface imaging (3D-SI) of the breasts enables the measurement of breast volume and shape symmetry. If these measurements were sufficiently accurate and repeatable, they could be used in planning oncological breast surgery and as an objective measure of aesthetic outcome. The aim of this study was to validate the measurements of breast volume and symmetry provided by the Vectra XT imaging system.MethodsTo validate measurements, breast phantom models of true volume between 100 and 1000 cm3 were constructed and varying amounts removed to mimic breast tissue ‘resections’. The volumes of the phantoms were measured using 3D-SI by two observers and compared to a gold standard. For intra-observer repeatability and inter-observer reproducibility in vivo, 16 patients who had undergone oncological breast surgery had breast volume and symmetry measured three times by two observers.ResultsA mean relative difference of 2.17 and 2.28% for observer 1 and 2 respectively was seen in the phantom measurements compared to the gold standard (n = 45, Bland Altman agreement). Intra-observer variation over ten repeated measurements demonstrated mean coefficients of variation (CV) of 0.58 and 0.49%, respectively. The inter-observer variation demonstrated a mean relative difference of 0.11% between the two observers. In patients, intra-observer variation over three repeated volume measurements for each observer was 3.9 and 3.8% (mean CV); the mean relative difference between observers was 5.78%. For three repeated shape symmetry measurements using RMS projection difference between the two breasts, the intra-observer variations were 8 and 14% (mean CV), the mean relative difference between observers was 0.43 mm for average symmetry values that ranged from about 3.5 to 15.5 mm.ConclusionThis first validation of breast volume and shape symmetry measurements using the Vectra XT 3D-SI system suggests that these measurements have the potential to assist in pre-operative planning and also as a measure of aesthetic outcome.

A new three-dimensional nonscanning laser imaging system based on the illumination pattern of a point-light-source array.

One of the most important goals of research on three-dimensional nonscanning laser imaging systems is the improvement of the illumination system. In this paper, a new three-dimensional nonscanning laser imaging system based on the illumination pattern of a point-light-source array is proposed. This array is obtained using a fiber array connected to a laser array with each unit laser having independent control circuits. This system uses a point-to-point imaging process, which is realized using the exact corresponding optical relationship between the point-light-source array and a linear-mode avalanche photodiode array detector. The complete working process of this system is explained in detail, and the mathematical model of this system containing four equations is established. A simulated contrast experiment and two real contrast experiments which use the simplified setup without a laser array are performed. The final results demonstrate that unlike a conventional three-dimensional nonscanning laser imaging system, the proposed system meets all the requirements of an eligible illumination system. Finally, the imaging performance of this system is analyzed under defocusing situations, and analytical results show that the system has good defocusing robustness and can be easily adjusted in real applications.

Demonstration of a laparoscopic structured-illumination three-dimensional imaging system for guiding reconstructive bowel anastomosis.

.This paper reports the development and system analysis of a laparoscopic system based on structured illumination technique capable of three-dimensional (3-D) reconstruction of porcine intestine during surgical anastomosis (connection of tubular structures). A calibration target is used to validate the system performance and results show a depth of field of 20 mm with an accuracy of 0.008 mm and precision of 0.25 mm. The imaging system is used to reconstruct a quantitative 3-D depth measurement of ex vivo porcine bowel tissues to mimic an end-to-end bowel anastomosis scenario. We demonstrate that the system can detect a suture in the tissue and map homogeneous surfaces of the intestine with different tissue pigments, affirming the feasibility for depth quantization for guiding and assisting medical diagnostic decisions in anastomosis surgery.

Spatial-temporal human gesture recognition under degraded conditions using three-dimensional integral imaging.

We present spatial-temporal human gesture recognition in degraded conditions including low light levels and occlusions using passive sensing three-dimensional (3D) integral imaging (InIm) system and 3D correlation filters. The 4D (lateral, longitudinal, and temporal) reconstructed data is processed using a variety of algorithms including linear and non-linear distortion-invariant filters; and compared with previously reported space-time interest points (STIP) feature detector, 3D histogram of oriented gradients (3D HOG) feature descriptor, with a standard bag-of-features support vector machine (SVM) framework, etc. The gesture recognition results with different classification algorithms are compared using a variety of performance metrics such as receiver operating characteristic (ROC) curves, area under the curve (AUC), SNR, the probability of classification errors, and confusion matrix. Integral imaging video sequences of human gestures are captured under degraded conditions such as low light illumination and in the presence of partial occlusions. A four-dimensional (4D) reconstructed video sequence is computed that provides lateral and depth information of a scene over time i.e. (x, y, z, t). The total-variation denoising algorithm is applied to the signal to further reduce noise and preserve data in the video frames. We show that the 4D signal consists of decreased scene noise, partial occlusion removal, and improved SNR due to the computational InIm and/or denoising algorithms. Finally, gesture recognition is processed with classification algorithms, such as distortion-invariant correlation filters; and STIP, 3D HOG with SVM, which are applied to the reconstructed 4D gesture signal to classify the human gesture. Experiments are conducted using a synthetic aperture InIm system in ambient light. Our experiments indicate that the proposed approach is promising in detection of human gestures in degraded conditions such as low illumination conditions with partial occlusion. To the best of our knowledge, this is the first report on spatial-temporal human gesture recognition in degraded conditions using passive sensing 4D integral imaging with nonlinear correlation filters.

Passive ranging and a three-dimensional imaging system through wavefront coding**Project supported by the National Natural Science Foundation of China (Grant No. 61205158) and the Natural Science Foundation of Zhejiang Province, China (Grant No. LY15F050013).

A single-image passive ranging and three-dimensional (3D) imaging system with chiral phase encoding was proposed in 2011 [Opt. Lett. 36, 115 (2011)]. A new theoretical analysis of the system in space domain is presented in this paper. We deduce the analytic relationships between the object distance and the point spread function, and between the object distance and the encoded image, respectively. Both the point spread function and the processed spectrum of the encoded image have two spots, which will rotate with the variation of the object distance. Then the depth map is extracted from the encoded image and it can be used to set up 3D images. The theoretical analysis is verified by a wavefront coding system with a chiral phase which is generated by a phase-only liquid-crystal spatial light modulator. The phase generated by the liquid-crystal spatial light modulator is more flexible than the fixed phase mask and can be adjusted in real time. It is especially suitable for observing the object with a large depth of field.

Fully Automatic Three-Dimensional Ultrasound Imaging Based on Conventional B-Scan.

Robotic ultrasound systems have turned into clinical use over the past few decades, increasing precision and quality of medical operations. In this paper, we propose a fully automatic scanning system for three-dimensional (3-D) ultrasound imaging. A depth camera was first used to obtain the depth data and color data of the tissue surface. Based on the depth image, the 3-D contour of the tissue was rendered and the scan path of ultrasound probe was automatically planned. Following the scan path, a 3-D translating device drove the probe to move on the tissue surface. Simultaneously, the B-scans and their positional information were recorded for subsequent volume reconstruction. In order to stop the scanning process when the pressure on the skin exceeded a preset threshold, two force sensors were attached to the front side of the probe for force measurement. In vitro and in vivo experiments were conducted for assessing the performance of the proposed system. Quantitative results show that the error of volume measurement was less than 1%, indicating that the system is capable of automatic ultrasound scanning and 3-D imaging. It is expected that the proposed system can be well used in clinical practices.

Digital volume tomography : Dedicated scanner and cone beam CT with C‑arm systems

Digital volume tomography (DVT) and cone-beam computed tomography (CT) with C‑arm systems have become established three-dimensional imaging systems as an alternative to CT in some application areas. The technology of the systems is well developed so that they have become acompeting method to CT imaging in terms of image quality and radiation exposure. An advantage is the better spatial resolution, preferably with dedicated scanner systems, especially in the z direction. The radiation exposure of CT, cone beam CT and DVT are comparable, if the exposure parameter in CT imaging can be adjusted to the lower exposure levels. Advantages of these systems are that they can be used for imaging in abetter workflow or to acquire images under conditions not possible in CT, e. g. imaging under stress in orthopedics or to take images in the corona technique with ahorizontal gantry in cone-beam CT mammography PRACTICAL RECOMMENDATIONS: The use of three-dimensional imaging is becoming more frequent and will replace planar radiography in additional clinical situations. The three-dimensional imaging without superpositioning of structures has advantages in the visibility of structures and the spatial relation to other organs and structures. In guidelines and recommendations, the number of recommendations given for the use of three-dimensional imaging is increasing. This leads to asmall increase in the radiation exposure of patients, a trend which is reflected in the annual reports of the Federal Office for Radiation Protection.

Reduction effect of the quantity of radiation exposure and contrast media by image support system in transarterial chemoembolization for the treatment of hepatocellular carcinoma.

We confirmed the clinical utility of a three-dimensional navigation system during transarterial chemoembolization. We evaluated 128 tumors in 91 patients enrolled between May 2015 and August 2016. We evaluated the accuracy of the three-dimensional navigation imaging system for all tumors. We compared the patients who were able to undergo route detection using three-dimensional navigation with previously treated patients who underwent transarterial chemoembolization without using three-dimensional navigation (n=21). For 38 patients who underwent super-selective microcatheter insertion after a feeding artery was identified by three-dimensional navigation, we confirmed the relationship between the tumors and contrasted liver parenchyma and divided the computed tomography hepatic arteriography findings into four grades. Grade 1: an overlap of >5mm, grade 2: an overlap between 0 and 5mm, grade 3: the borders of the tumor within the liver parenchyma but in contact with the edges, and grade 4: a tumor outside the borders of the liver parenchyma. Using the three-dimensional navigation system, we identified a tumor-feeding artery in 125/128 tumors (97.6%). Furthermore, this system allowed us to significantly reduce the volume of contrast media and the radiation exposure dose in patients undergoing an evaluation. We identified 15 grade 1 tumors (39.5%), 3 grade 2 tumors (7.9%), 11 grade 3 tumors (28.9%), and 9 grade 4 tumors (23.7%) according to our definitions. The three-dimensional navigation is useful not only for patients but also for surgeons who have relatively little experience.

Three-dimensional imaging of magnetic nanoparticles using multiple pickup coils and field-free line

We performed three-dimensional detection of magnetic nanoparticle (MNP) samples using third-harmonic signal detection. In this method, a combination of five pickup coils and a gradient field with a field-free line was used to acquire three-dimensional MNP sample position information. The resulting two-dimensional maps of the signal fields generated by the MNP samples are sufficient for three-dimensional MNP image reconstruction. In the experiments, two MNP samples with different Fe contents were set at different positions. Two-dimensional field maps were measured using the five pickup coils, and the three-dimensional MNP sample distribution was then reconstructed from these field maps by solving an inversion problem. We demonstrated three-dimensional detection of two MNP samples where we reconstructed the three-dimensional positions and the Fe contents of these two MNP samples with reasonable accuracy. These results indicate the feasibility of the proposed system for three-dimensional magnetic particle imaging.

Three-Dimensional Speckle Light Self-Healing-Based Imaging System

Recently new methodologies for imaging have been achieved making use of multiple light scattering. Here we present the self-healing effect using a speckled light field. We present an experiment that constitutes a useful application for a three-dimensional light sheet-based imaging system through an inhomogeneous medium. Each layer can be imaged independently of the others. The axial resolution basically depends on the coherence length, which can be sub-wavelength and controllable. This allows for a simple and direct technique for imaging through scattering layers with axial resolution improvement. Our results may find applications not only in bio-microscopy systems but also in data transmission.

Terahertz Radome Inspection

Radomes protecting sensitive radar, navigational, and communications equipment of, e.g., aircraft, are strongly exposed to the environment and have to withstand harsh weather conditions and potential impacts. Besides their significance to the structural integrity of the radomes, it is often crucial to optimize the composite structures for best possible radio performance. Hence, there exists a significant interest in non-destructive testing techniques, which can be used for defect inspection of radomes in field use as well as for quality inspection during the manufacturing process. Contactless millimeter-wave and terahertz imaging techniques provide millimeter resolution and have the potential to address both application scenarios. We report on our development of a three-dimensional (3D) terahertz imaging system for radome inspection during industrial manufacturing processes. The system was designed for operation within a machining center for radome manufacturing. It simultaneously gathers terahertz depth information in adjacent frequency ranges, from 70 to 110 GHz and from 110 to 170 GHz by combining two frequency modulated continuous-wave terahertz sensing units into a single measurement device. Results from spiraliform image acquisition of a radome test sample demonstrate the successful integration of the measurement system.