Three-dimensional Imaging System Research Articles

Single-pixel three-dimensional imaging with time-based depth resolution.

Time-of-flight three-dimensional imaging is an important tool for applications such as object recognition and remote sensing. Conventional time-of-flight three-dimensional imaging systems frequently use a raster scanned laser to measure the range of each pixel in the scene sequentially. Here we show a modified time-of-flight three-dimensional imaging system, which can use compressed sensing techniques to reduce acquisition times, whilst distributing the optical illumination over the full field of view. Our system is based on a single-pixel camera using short-pulsed structured illumination and a high-speed photodiode, and is capable of reconstructing 128 × 128-pixel resolution three-dimensional scenes to an accuracy of ∼3 mm at a range of ∼5 m. Furthermore, by using a compressive sampling strategy, we demonstrate continuous real-time three-dimensional video with a frame-rate up to 12 Hz. The simplicity of the system hardware could enable low-cost three-dimensional imaging devices for precision ranging at wavelengths beyond the visible spectrum.

Thoracoscopic anatomic pulmonary segmentectomy: a 3-dimensional guided imaging system for lung operations.

To evaluate the Lung Operation Three-dimensional Imaging System software by Xiamen TRONG Technology Co. Ltd in detecting the precise position of solitary pulmonary nodules or ground-glass opacity nodules before surgery. Chest, arterial phase, portal venous phase, enhanced and delayed-phase images of 10 cases with 12 nodules were obtained with a Toshiba Aquilion One 320 computed tomography (CT) scanner. According to the image data of the nodules, 0.5 mm thick images of 320-row multislice CT scanners were reconstructed as 3D images, and the boundary of each segment was automatically partitioned and pigmented in accordance with the pulmonary artery system. To locate the nodules, the 3D images and coloured segments were merged. The clearly labelled lung structure was utilized in a preoperative virtual segmentectomy and the subsequently planned thoracoscopic surgery. In all 10 cases, the reconstruction of the pulmonary artery could image branches as far as Grade 5. The anatomically adjacent relationship of the nodules among the arteries, veins and bronchi in the target pulmonary segments could be displayed in any view. The thoracoscopic anatomic pulmonary segmentectomy was performed successfully. All 12 nodules, which had deeply settled in the parenchyma, were resected using the virtual planning software and diagnosed pathologically. The software can be used preoperatively as a tracing method to identify the location of nodules in most general thoracic surgeries, subsequently providing guidance during the surgery.

Contrast sensitivity function in stereoscopic viewing of Gabor patches on a medical polarized three-dimensional stereoscopic display

While three-dimensional (3-D) imaging systems are entering hospitals, no study to date has explored the luminance calibration needs of 3-D stereoscopic diagnostic displays and if they differ from two-dimensional (2-D) displays. Since medical display calibration incorporates the human contrast sensitivity function (CSF), we first assessed the 2-D CSF for benchmarking and then examined the impact of two image parameters on the 3-D stereoscopic CSF: (1) five depth plane (DP) positions (between DP: −171 and DP: 2853 mm), and (2) three 3-D inclinations (0 deg, 45 deg, and 60 deg around the horizontal axis of a DP). Stimuli were stereoscopic images of a vertically oriented 2-D Gabor patch at one of seven frequencies ranging from 0.4 to 10 cycles/deg. CSFs were measured for seven to nine human observers with a staircase procedure. The results indicate that the 2-D CSF model remains valid for a 3-D stereoscopic display regardless of the amount of disparity between the stereo images. We also found that the 3-D CSF at DP≠0 does not differ from the 3-D CSF at DP=0 for DPs and disparities which allow effortless binocular fusion. Therefore, the existing 2-D medical luminance calibration algorithm remains an appropriate tool for calibrating polarized stereoscopic medical displays.

Pixel multiplexing technique for real-time three-dimensional-imaging laser detection and ranging system using four linear-mode avalanche photodiodes.

The avalanche-photodiode-array (APD-array) laser detection and ranging (LADAR) system has been continually developed owing to its superiority of nonscanning, large field of view, high sensitivity, and high precision. However, how to achieve higher-efficient detection and better integration of the LADAR system for real-time three-dimensional (3D) imaging continues to be a problem. In this study, a novel LADAR system using four linear mode APDs (LmAPDs) is developed for high-efficient detection by adopting a modulation and multiplexing technique. Furthermore, an automatic control system for the array LADAR system is proposed and designed by applying the virtual instrumentation technique. The control system aims to achieve four functions: synchronization of laser emission and rotating platform, multi-channel synchronous data acquisition, real-time Ethernet upper monitoring, and real-time signal processing and 3D visualization. The structure and principle of the complete system are described in the paper. The experimental results demonstrate that the LADAR system is capable of achieving real-time 3D imaging on an omnidirectional rotating platform under the control of the virtual instrumentation system. The automatic imaging LADAR system utilized only 4 LmAPDs to achieve 256-pixel-per-frame detection with by employing 64-bit demodulator. Moreover, the lateral resolution is ∼15 cm and range accuracy is ∼4 cm root-mean-square error at a distance of ∼40 m.

Validity and repeatability of a depth camera-based surface imaging system for thigh volume measurement

ABSTRACTComplex anthropometrics such as area and volume, can identify changes in body size and shape that are not detectable with traditional anthropometrics of lengths, breadths, skinfolds and girths. However, taking these complex with manual techniques (tape measurement and water displacement) is often unsuitable. Three-dimensional (3D) surface imaging systems are quick and accurate alternatives to manual techniques but their use is restricted by cost, complexity and limited access. We have developed a novel low-cost, accessible and portable 3D surface imaging system based on consumer depth cameras. The aim of this study was to determine the validity and repeatability of the system in the measurement of thigh volume. The thigh volumes of 36 participants were measured with the depth camera system and a high precision commercially available 3D surface imaging system (3dMD). The depth camera system used within this study is highly repeatable (technical error of measurement (TEM) of <1.0% intra-calibration and ~2.0% inter-calibration) but systematically overestimates (~6%) thigh volume when compared to the 3dMD system. This suggests poor agreement yet a close relationship, which once corrected can yield a usable thigh volume measurement.

Depth-of-focus Resolution and Viewing Angle Improvement of Integral Imaging System Using Multi-directional Projections and Non-uniform Lenslets Array with Intermediate View Reconstruction Method

This study presents a three-dimensional (3-D) integral imaging system to improve concurrently the viewing angle, Depth-Of-Focus (DOF) and resolution of the reconstructed object images by using multi-directional projections and non-uniform lenslets array with Intermediate-View Reconstruction Method (IVRM). In this method, each elemental lens array collects multi-directional illuminations of multiple Elemental Image (EI) sets and generates multiple Point Light Sources (PLSs) at the different positions in the two focal planes. The viewing zone and depth-of-focus is larger than the conventional method because of multi-directional projections of multiple EI sets and non-uniform lenslets; whereas a conventional method produces a viewing zone using only a single set of EI projection and uniform lenslets. For the non-uniform lenslets, DOF-improved integral images of 3-D objects can be picked-up and then by applying the IVRM to these picked-up integral images. Hence, the viewing angle, DOF as well as resolution enhanced object images can be reconstructed. To find out the possibility of the proposed system, experimental results are discussed with mathematical expressions.

Application of the Intraoperative Dual Photon Emission Computed Tomography System in Sentinel Lymph Node Detection: A Simulation Study

The sentinel lymph node (SLN) hypothesis is applied as part of the standard procedure for identifying early-stage breast cancer. Thus, an imaging system that can locate SLNs in operating rooms is desired. Many 2-D probe imaging systems and a freehand single-photon emission-computed tomography (fhSPECT) system have been proposed. However, 2-D probe imaging systems are affected by shine-through and shadowing effects. Here, we propose an alternative to 3-D imaging systems, i.e., a dual-photon emission computed tomography (DuPECT) system, which integrates both preoperative and intraoperative information to locate SLNs using cascade isotopes such as Se-75. The system consists of a ${\rm LaBr}_{3}$ -based probe and planar head, a collimation system, and a coincidence circuit. For each disintegration, the slat and parallel-hole collimator define a plane and a line, respectively, which represent the possible flight paths of each photon. SLNs can be located using the line-plane intersection. Here, the performance is evaluated using Monte Carlo software developed in our laboratory, integrated with SimSET and GATE software. A measurement study indicates that the randoms rate increases with increased initial activities, while the scatter rate is lower than 1.2 count/s for various activities. In a simulated imaging study, four injection sites and two LNs placed at various depths are minimally distinguishable. However, the LNs are clearly identifiable in the absence of injection sites. Our results indicate that the proposed three-dimensional imaging system has the potential to identify injection sites and various SLNs. However, difficulties with low sensitivity for LN detection, especially in the presence of activity from injection sites, and the choice of appropriate radioisotope must be overcome for its clinical usage.

Depth estimation in Integral Imaging based on a maximum voting strategy

An approach that uses the scene information acquired by means of a three-dimensional (3D) synthetic aperture integral imaging system is presented. This method generates a depth map of the scene through a voting strategy. In particular, we consider the information given by each camera of the array for each pixel, and also the local information in the neighbourhood of that pixel. The proposed method obtains consistent results for any type of object surfaces as well as very sharp boundaries. In addition, we also contribute in this paper with a repository of a set of synthetic integral images generated by 3DS Max where the so-called ground truth (real-true depth map) is available. This resource can be used as a benchmark to test any Integral Imaging based range estimation method.

Research of Fast 3D Imaging Based on Multiple Mode

Three-dimensional (3D) imaging has received increasingly extensive attention and has been widely used currently. Lots of efforts have been put on three-dimensional imaging method and system study, in order to meet fast and high accurate requirement. In this article, we realize a fast and high quality stereo matching algorithm on field programmable gate array (FPGA) using the combination of time-of-flight (TOF) camera and binocular camera. Images captured from the two cameras own a same spatial resolution, letting us use the depth maps taken by the TOF camera to figure initial disparity. Under the constraint of the depth map as the stereo pairs when comes to stereo matching, expected disparity of each pixel is limited within a narrow search range. In the meanwhile, using field programmable gate array (FPGA, altera cyclone IV series) concurrent computing we can configure multi core image matching system, thus doing stereo matching on embedded system. The simulation results demonstrate that it can speed up the process of stereo matching and increase matching reliability and stability, realize embedded calculation, expand application range.

Evaluation of the Reproducibility of Nonverbal Facial Expressions Using a 3D Motion Capture System

To evaluate the reproducibility of three nonverbal facial expressions using a three-dimensional motion capture system. Prospective, cross-sectional, controlled study. Glasgow Dental Hospital and School, University of Glasgow, United Kingdom. Thirty-two subjects, 16 males and 16 females. With a three-dimensional video passive stereophotogrammetry imaging system, maximal smile, cheek puff, and lip purse were captured for each subject. Anatomical facial landmarks were digitized on the first frame and then tracked automatically. The same facial expressions were captured 15 minutes later. The magnitude of each expression and speed of landmark displacement were calculated. The landmark motion curves were spatially and temporally aligned to calculate the similarity of the dynamic movements of the same landmarks between the captures. There were no significant differences between individuals for magnitude (P = .892) or for speed (P = .456). There were significant differences in landmark movement similarity (P = .011); similarity was more reproducible for maximal smile. There was no significant gender effect on the difference in magnitude. There was a significant gender effect on speed to reach maximal smile (P = .044) and a pursed-lip expression (P = .038). There was a significant gender effect on landmark movement similarities (P = .031) for cheek puff expression. There were no differences in magnitude and speed for maximal smile, cheek puff, and lip purse between the two captures for all participants. For individual expressions, maximal smile expression had the highest similarity value for individual landmarks.

Improving the Face of Cosmetic Medicine: An Automatic Three-dimensional Analysis System for Facial Rejuvenation

Precision imaging in medicine using ultrasound, X-rays, MR, CT and PET scans is generally of the highest importance in patient management. These technologies are often relied upon as integral components for quantitative assessment of the patient’s initial presentation and progress. By contrast, initial assessment and recording outcomes of aesthetic procedures is largely limited to 2D photography and subjective feedback from the patient. In this report, the authors provide insight into an Australian Government-funded four-part research program that aims to produce: (1) A high definition three-dimensional imaging system that produces quantitative assessment of outcomes in facial rejuvenation that is costeffective, user-friendly, and time-efficient; (2) A predictive modeling of potential outcomes prior to treatment derived from real data; (3) A high definition threedimensional imaging system that illustrates changes in facial movements in response to facial rejuvenation treatments; (4) A predictive modeling of dynamic movements of the facial features as a response to a planned treatment program derived from real data.

The effect of Vasohibin-1 expression and tumor-associated macrophages on the angiogenesis in vitro and in vivo.

Vasohibin-1 is an intrinsic inhibitor of angiogenesis induced by VEGF-A. However, there little is known about the relationship between Vasohibin-1 expression, angiogenesis, and tumor-associated macrophages (TAMs). Vasohibin-1 expression, VEGF-A expression, microvessel density (MVD) marked with CD34, and density of cells marked with CD68 were measured in 111 paraffin-embedded tissues of gastric cancer by immunohistochemistry. The length of tube forming structures of endothelial cells and mobility rate of gastric cancer cells in Matrigel were tested by three-dimensional live cell imaging system. The effect of TAMs on the tumor growth, MVD, and Vasohibin-1 expression was measured by nude mice tumor genesis assay in vivo. We found that high Vasohibin-1 protein expression correlated significantly with worse TNM stage (P = 0.002), metastatic lymph node (P = 0.014), distant metastasis (P = 0.022), overall survival (P < 0.001), and progression-free survival (P < 0.001) compared to those with low Vasohibin-1 expression. Vasohibin-1 protein expression had statistical correlation with the MVD (r = 0.860, P < 0.001), density of CD68(+) cells (r = 0.882, P < 0.001), and VEGF-A expression (r = 0.719, P < 0.001) in the gastric cancer tissues. Decreasing Vasohibin-1 expression with siRNA increased the length of tube forming structures of endothelial cells in co-culture with endothelial cells (EA-hy923), macrophages, and gastric cancers (Hs746T). Tumor volume (P = 0.001), Vasohibin-1 (P < 0.001), and VEGF-A (P < 0.001) expression in mice inoculated with AGS and THP (10:1) was significantly higher than that with AGS alone (P = 0.001). Vasohibin-1 protein expression had statistical correlation with VEGF expression (r = 0.786, P < 0.001) and MVD (r = 0.496, P = 0.014) in gastric xenografted tumor. Therefore, Vasohibin-1 might be a potential marker of worse prognosis and therapeutic target in gastric cancer. Vasohibin-1 might play an important role in the process of angiogenesis regulated by TAMs.

Laser ranging and three-dimensional imaging systems based on the differential optical path method

Abstract In order to suppress the effects of common-mode noise, laser ranging and three-dimensional imaging systems based on the differential optical-path method (DOPM) are proposed. Compared with the traditional method based on single receiver, DOPM uses two receivers which have different optical-paths. Based on DOPM, we developed the laser ranging and three-dimensional (3D) imaging systems and carried out ranging and three-dimensional imaging experiments to research DOPM for practical application. In ranging experiments, the root-mean-square (RMS) of ranging error decreases from 95 to 70 mm; as a result the error could be decreased to 74% of the method based on a single receiver. Meanwhile, the system obtains the highest sensitivity when differential distance is multiplied by light speed and receiving pulse width. In 3D imaging experiments, compared with the traditional method, the mean RMS of 64 channels based on DOPM decreases from 99 to 65 mm, which decreases to 66%. Meanwhile, DOPM improves the range resolution and could distinguish two targets with height difference of 80 mm.

Computed Optical Interferometric Imaging: Methods, Achievements, and Challenges.

Three-dimensional high-resolution optical imaging systems are generally restricted by the trade-off between resolution and depth-of-field as well as imperfections in the imaging system or sample. Computed optical interferometric imaging is able to overcome these longstanding limitations using methods such as interferometric synthetic aperture microscopy (ISAM) and computational adaptive optics (CAO) which manipulate the complex interferometric data. These techniques correct for limited depth-of-field and optical aberrations without the need for additional hardware. This paper aims to outline these computational methods, making them readily available to the research community. Achievements of the techniques will be highlighted, along with past and present challenges in implementing the techniques. Challenges such as phase instability and determination of the appropriate aberration correction have been largely overcome so that imaging of living tissues using ISAM and CAO is now possible. Computed imaging in optics is becoming a mature technology poised to make a significant impact in medicine and biology.

Modeling and simulations of three-dimensional laser imaging based on space-variant structure

A three-dimensional (3D) laser imaging system based on time of flight is proposed, based on the human retina structure. The system obtains 3D images with space-variant resolution, and we further establish mathematical models of the system and carried out simulative comparison between space-variant structure (SVS) and space-invariant structure (SIS). The system based on SVS produces significant improvements over traditional system based on SIS in the following aspects: (1) The system based on SVS uses less pixels than that based on SIS under the same field of view (FOV) and resolution. Therefore, this property is more suitable for uses in situations that require high speed and large volume data processing. (2) The system based on SVS has higher efficiency of utilization of photodiode array than that based on SIS. (3) 3D image based on SVS has the properties of rotation and scaling invariance. (4) The system based on SVS has higher echo power in outside ring of large photodiode array, which is more effective in detecting targets with low reflectance.

광 스캐닝 홀로그래피를 이용한 양안식 3차원 홀로그래픽 영상 시스템

In this paper we propose a binocular holographic three-dimensional (3D) imaging system using optical scanning holography. To realize a binocular 3D holographic imaging system, we could acquire the complex holograms of a real object after designing a holographic display system based on interpupillary distance and pupil size, and these holograms could be optically reconstructed following numerical signal processing with an amplitude spatial light modulator. The proposed binocular 3D holographic imaging system using optical scanning holography was verified experimentally.

Ultrafast Three-Dimensional Serial Time-Encoded Imaging With High Vertical Resolution

A three-dimensional (3-D) serial time-encoded imaging system with a high vertical resolution based on microwave phase or frequency detection is proposed and experimentally demonstrated. A regular serial time-encoded imaging system can perform ultrafast two-dimensional imaging in which the reflectivity of a sample surface is represented by the intensity change of a microwave waveform. By adding one reference channel to form a Mach–Zehnder interferometer structure, the depth information of the sample surface is encoded as the microwave phase or frequency change, thus, 3-D imaging is implementable by extracting the phase or frequency information. In the proposed approach, the intensity and phase or frequency information are extracted based on Hilbert transform from the microwave waveform. The approach is experimentally evaluated. The imaging of a silicon chip as a sample is performed. A vertical resolution better than 130 nm and a depth measurement range greater than 2 mm are demonstrated.

Quantitative magnetometry of ferromagnetic nanorods by microfluidic analytical magnetophoresis

We introduce an implementation of magnetophoresis to measure the absolute magnetization of ferromagnetic nanorods dispersed in fluids, by analyzing the velocity of single nanorods under an applied magnetic field gradient. A microfluidic guideway prevents aggregation of nanorods, isolates them, and confines their motion for analysis. We use a three-dimensional imaging system to precisely track nanorod velocity and particle-surface proximity. We test the effect of the guideway on nanorod velocity under field gradient application, finding that it guides magnetophoresis, but imposes insignificant drag beyond that of a planar surface. This result provides insight into the transport of magnetic nanorods at microstructured interfaces and allows the use of an analytical model to accurately determine the reacted viscous drag in the force balance needed for quantitative magnetometry. We also estimate the confining potential of the guideway with Brownian motion measurements and Boltzmann statistics. We use our technique to measure the magnetization of ferromagnetic nanorods with a noise floor of 8.5 × 10−20 A·m2·Hz−½. Our technique is quantitative, rapid, and scalable for determining the absolute magnetization of ferromagnetic nanoparticles with high throughput.

Enhanced Crack Segmentation Algorithm Using 3D Pavement Data

AbstractAutomatic pavement crack segmentation has gained attention among researchers and transportation agencies over the past two decades. However, most existing algorithms using two-dimensional (2D) pavement intensity images cannot provide a satisfactory performance. With the advent of sensing technology, three-dimensional (3D) line laser pavement imaging systems have become available. The objective of this paper is to propose an enhanced dynamic optimization algorithm employing the advantages of 3D pavement data to improve crack segmentation. The proposed algorithm consists of three major stages. First, a two-step Gaussian filter is applied to remove outliers from the collected laser data and rectify the profile in order to reduce the influence of cross-slope and ruts on crack segmentation. Then, a rough crack segmentation stage is conducted to adaptively identify the crack regions of interest. Finally, a bounding box and major orientation for each valid crack region of interest will provide searching ...

High resolution three-dimensional photoacoustic imaging of human finger joints in vivo

We present a method for noninvasively imaging the hand joints using a three-dimensional (3D) photoacoustic imaging (PAI) system. This 3D PAI system utilizes cylindrical scanning in data collection and virtual-detector concept in image reconstruction. The maximum lateral and axial resolutions of the PAI system are 70 μm and 240 μm. The cross-sectional photoacoustic images of a healthy joint clearly exhibited major internal structures including phalanx and tendons, which are not available from the current photoacoustic imaging methods. The in vivo PAI results obtained are comparable with the corresponding 3.0 T MRI images of the finger joint. This study suggests that the proposed method has the potential to be used in early detection of joint diseases such as osteoarthritis.