Impact of Three‐Dimensional Vision in Laparoscopic Training

3D imaging for on-farm estimation of live cattle traits and carcass weight prediction.

Laser three-dimensional (3D) image is a novel non-cooperative target 3D image acquisition technology, and the improvements in detection capability and imaging accuracy of the system are critically dependent on efficient echo-signal processing technique and 3D reconstruction method. The registration process is an essential step in array 3D imaging laser point cloud data processing. Registration of point clouds is an effective method that solves the problem caused by the target self-occlusion in the laser 3D imaging system. The accurate registration result will help provide better support for subsequent applications, such as object reconstruction and target recognition. In this study, a set of thresholds in the iterative closest point (ICP) algorithm is analysed on the basis of the characteristics of the laser array 3D imaging system and is combined with the range error and visual lateral resolution of the system, which are both important parameters in the imaging system. To improve the accuracy and speed of registration, the stop threshold of the iterative algorithm and the corresponding point-distance threshold in the algorithm are established in a novel way based on the range error and visual lateral resolution of the system. This forms the foundation, based on which an adaptive threshold ICP algorithm is proposed. The principal idea of the algorithm is to improve the threshold set that has a considerable effect on the accuracy and speed of registration. At first, the characteristics of the imaging point clouds of the laser array 3D imaging system are analysed in the algorithm. Based on this analysis, the distance between the two point clouds and corresponding points with ideal registrations are estimated theoretically, according to the range error and visual lateral resolution of the system. The simulation results show that the theoretically estimated results and actual results have the same variation tendency, thus providing a theoretical basis for subsequent improvements. Next, the estimated results are added according to the iterative closest point algorithm. This implies that the registration thresholds are capable of changing and adapting under different iterations and imaging systems, thus improving the speed and accuracy of registrations. This phenomenon is not seen in other algorithms. Experiments involving laser array imaging of a point cloud and laser scanning of depth imaging data show that the algorithm is practical and effective for both imaging types of point clouds and can improve the speed and accuracy of registration notably. The effectiveness and feasibility of the proposed algorithm are thus verified. In addition, for its full consideration of the imaging system, the basic idea of the proposed algorithm can be used for designing future applications as required.

Three-dimensional (3D) imaging systems are being researched extensively for purposes of sensing and visualization in fields as diverse as defense, medical, art, and entertainment. When compared to traditional 2D imaging techniques, 3D imaging offers advantages in ranging, robustness to scene occlusion, and target recognition performance. Amongst the myriad 3D imaging techniques, 3D multiperspective imaging technologies have received recent attention due to the technologies’ relatively low cost, scalability, and passive sensing capabilities. Multiperspective 3D imagers collect 3D scene information by recording 2D intensity information from multiple perspectives, thus retaining both ray intensity and angle information. Three novel developments in 3D sensing, imaging, and visualization systems are presented: 3D imaging with axially distributed sensing, 3D optical profilometry, and occluded 3D object tracking.

Background:The number of surgical residency applicants has been declining. Early introduction of the discipline of surgery is thought to stimulate early interest in surgical residency. This study investigated the hypothesis that a laparoscopic skills course introduced in preclinical years would stimulate student interest in entering surgical residency.Methods:Preclinical medical students participated in a laparoscopic skills training course. All students underwent an animate laboratory at the beginning and at the end of the course. Students were divided into 4 separate groups: virtual reality, box trainer, both trainers, and control group. Before and after the course, students were asked their residency interest. First- and second-year medical students participated in the course.Results:Before the course, 56% of the students desired to go into general surgery or a surgical subspecialty. After the course, 49% of the students expressed interest in entering general surgery or a surgical subspecialty. A decrease occurred in students who desired to go into surgical subspecialty residency from 31% to 15% (P=NS), and an increase occurred in students who desired to go into general surgery residency from 25% to 34% (P=NS). No statistically significant difference was seen in the 4 individual training subgroup analyses.Conclusions:Participation in a laparoscopic skills course does not affect medical student interest in entering surgical residency. A trend was noted in students choosing general surgery over surgical subspecialty training after this course. Surgical educators need to investigate methods to encourage preclinical medical student interest in surgical residencies.

3D ultrasound imaging is becoming increasingly prevalent in the medical field. Compared to conventional 2D imaging systems, 3D imaging can provide a detailed view of tissue structures that makes diagnosis easier for the physicians. In addition, 2D image slices can be formed at various orientations to the transducer, making the examination less dependent on the skill of the sonographer. However, various challenges exist in developing a 3D imaging system, such as integration of a large number of elements, as well as post-processing of datasets received from a large number of channels. 2D transducer arrays are typically integrated with custom ICs in the probe handle to perform some intermediate beamforming and to reduce the number of cable connections to the imaging system. Capacitive micromachined ultrasonic transducers (CMUTs) have emerged as an alternative to piezoelectric transducers. Being a MEMS device, they greatly benefit from flexibility and ease of fabrication, and can be seamlessly integrated with electronics. Previous work demonstrates 3D stacking of CMUTs and dummy ICs with an intermediate interposer layer. However, that represents more of a mechanical demonstration of 3D integration. In this paper, we present a fully functional 3D ultrasound imaging system comprising a 32×32 2D CMUT array, 3D-stacked with front-end ICs using flip-chip bonding technology. The imaging system is capable of capturing real-time volumetric ultrasound data, and displaying 2D and 3D ultrasound images.

Three-dimensional (3D) imaging, a recent technical innovation in laparoscopic surgery, has been postulated to enhance depth perception and facilitate operations. However, it has never been evaluated in conditions where the focus is close to the optical system. Thus, it is unclear whether 3D cameras can improve laparoscopic surgical performance in neonates and infants. We tested 3D versus two-dimensional (2D) vision during laparoscopic surgery in rabbits, mimicking the size of a neonatal patient. Cadaver New Zealand white rabbits (mean weight 2,755 g) were operated by two surgeons experienced in 2D laparoscopic surgery and two surgical residents (with basic skills in 2D laparoscopy). All surgeons had never performed 3D laparoscopic surgery. Animals underwent six operations: Nissen fundoplication, small bowel anastomosis, and closure of a diaphragmatic defect using either 2D or 3D. Primary endpoint was cumulative operating time and operating time of each operation. Secondary endpoints included the hemodynamic response and psychomental stress level of the surgeons. Finally, subjective data on depth perception were assessed by questionnaires. Cumulative operating time of all three types of operations was significantly shorter with 3D laparoscopy in experts (3D: 23.01 ± 5.65 min vs 2D: 29.51 ± 7.51 min, p < 0.01) and residents (3D: 27.95 ± 3.69 min vs 2D: 33.95 ± 6.21 min, p < 0.05). This effect could be shown for each operation in the expert group and the Nissen fundoplication in the resident group. There were no differences in the hemodynamic response as well as the psychomental stress level between 2D and 3D imaging. 3D provided better depth perception. 3D laparoscopy in small spaces is associated with a significant shorter operating time. It induces no additional physical or psychomental stress in surgeons naive to 3D imaging. 3D may therefore facilitate minimal invasive surgery in neonates and infants.

To validate the accuracy and reproducibility of linear measurements of three-dimensional (3D) images and to compare the measurements with the direct anthropometry method on cleft lip and palate (CLP) patients. Nineteen linear facial measurements were derived from 16 standardized surface landmarks obtained from 37 cleft patients (20 males, 17 females; mean age 23.84 years, standard deviation ± 6.02). They were taken manually with calipers and were compared with the digitally calculated distance on the 3D images captured using the VECTRA-M5 360° Imaging System with pre-marked landmarks. Another pair of 19 linear measurements were computed on the 3D images 2 weeks apart for intra- and inter-observer agreements. Statistical analyses used were paired t test, the Bland-Altman analysis, and the intra-class correlation coefficient (ICC) index. Most of the linear measurements showed no statistically significant differences between the proposed method and direct anthropometry linear measurements. Nevertheless, bias of the 3D imaging system is present in the linear measurements of the nose width and the upper vermillion height. The measurements' mean biases were within 2 mm, but the 95% limit of agreement was more than 2 mm. Intra- and inter-observer measurements generally showed good reproducibility. Four inter-observer measurements, the upper and lower face heights, nose width, and pronasale to left alar base were clinically significant. Measurements obtained from this 3D imaging system are valid and reproducible for evaluating CLP patients. The system is suitable to be used in a clinical setting for cleft patients. However, training of the operator is strictly advisable.

3D imaging is an upcoming technology in laparoscopic surgery, and recent studies have shown that the modern 3D technique is superior in an experimental setting. However, the first randomized controlled clinical trial in this context dates back to 1998 and showed no significant difference between 2D and 3D visualization using the first 3D generation technique, which is now more than 15years old. Positive results measured in an experimental setting considering 3D imaging on surgical performance led us to initiate a randomized controlled pragmatic clinical trial to validate our findings in daily clinical routine. Standard laparoscopic operations (cholecystectomy, appendectomy) were preoperatively randomized to a 2D or 3D imaging system. We used a surgical comfort scale (Likert scale) and the Raw NASA Workload TLX for the subjective assessment of 2D and 3D imaging; the duration of surgery was also measured. The results of 3D imaging were statistically significant better than 2D imaging concerning the parameters "own felt safety" and "task efficiency"; the difficulty level of the procedures in the 2D and 3D groups did not differ. Overall, the Raw NASA Workload TLX showed no significance between the groups. 3D imaging could be a possible advantage in laparoscopic surgery. The results of our clinical trial show increased personal felt safety and efficiency of the surgeon using a 3D imaging system. Overall of the procedures, the findings assessed using Likert scales in terms of own felt safety and task efficiency were statistically significant for 3D imaging. The individually perceived workload assessed with the Raw NASA TLX shows no difference. Although these findings are subjective impressions of the performing surgeons without a clear benefit for 3D technology in clinical outcome, we think that these results show the capability that 3D laparoscopy can have a positive impact while performing laparoscopic procedures.

Background. Laparoscopic surgery has gained popularity in the last few decades replacing open standard techniques in several procedures. While its use and scope expand, a standardized method of training and assessment in laparoscopic skills is lacking. Aim. To assess the effect of virtual reality (VR) training on laparoscopic surgical skills. Materials and Methods. It is a prospective, controlled study conducted at Sagar Hospital’s skill lab and Shanthi Hospital and Research Centre (SHRC). We included 27 post graduates in general surgery. They were divided into two groups. One group underwent training in VR Simulator for one week, 30 minutes each day. The second group received no training. Their proficiency while mobilizing the Gallbladder from its liver bed was assessed using a validated scale by a single blinded observer. Results. The statistical analysis was done using a non-parametric test (Mann-Whitney U test). Residents who underwent training in VR simulator got better scores in Overall rating and also in individual parameters when compared with the control group (P = &lt;0.05). Conclusions. Laparoscopic surgical skills can be increased by using proficiency-based VR simulator training and it can be transferred to actual operations. VR simulators are a valid tool for laparoscopic surgical skills training.

To establish a 3D ultrasound imaging system based on pulse-triggered image acquisition using the linear probe on the VerasonicsTM vantage 128 platform and evaluate its performance in scanning standard phantom and human carotid artery. The 3D ultrasound imaging system included 3 modules for probe motion control, image acquisition and storage, and 3D image reconstruction and display. To improve the precision of image acquisition, we used fixed frequency pulses to control the external trigger function combined with mechanical scanning. Voxel-based 3D reconstruction was used for image reconstruction and display. The user interface was designed to allow direct operations of the platform. We carried out scanning tests of standard ultrasound phantom and human carotid artery to evaluate the performance of this imaging system. We successfully constructed a 3D ultrasound imaging system based on pulse-triggered image acquisition. The results of standard phantom and human carotid scanning tests showed that each module of the system was fully functional. The self-designed user interface of this ultrasound imaging system allowed full control of the system functions for original image acquisition, 3D image reconstruction, and display of cross-sections in 3 different views. This 3D ultrasound imaging system achieves high-quality 3D ultrasound imaging and provides the basis for further study and clinical application of 3D ultrasound imaging.

Evaluation of the laparoscopic surgical skills of surgical residents is usually a subjective process carried out in the operating room by senior surgeons. The two hypotheses of the current study were: (1) haptic information and tool/tissue interactions (types and transitions) performed in laparoscopic surgery are skill-dependent, and (2) statistical models (Hidden Markov Models--HMMs) incorporating these data are capable of objectively evaluating laparoscopic surgical skills. Eight subjects (six residents--two first-year (R1), two third-year (R3), and two fifth-year (R5)--and two expert laparoscopic surgeons) performed laparoscopic cholecystectomy on pigs using an instrumented grasper equipped with force/torque (F/T) sensors at the hand/tool interface, and F/T data was synchronized with video of the operative maneuvers. Fourteen types of tool/tissue (T/T) interactions, each associated with unique F/T signatures, were defined from frame-by-frame video analysis. HMMs for each subject and step of the operation were compared to evaluate the statistical distance between expert surgeons and residents with different skill levels. The statistical distances between HMMs representing expert surgeons and residents were significantly different (alpha < 0.05). Major differences occurred in: (1) F/T magnitudes; (2) type of T/T interactions and transitions between them; and (3) time intervals for each T/T interaction and overall completion time. The greatest difference in performance was between R1 (junior trainee) and R3 (midlevel trainee). Smaller changes were seen as expertise increased beyond the R3 level. HMMs incorporating haptic and visual information provide an objective tool for evaluating surgical skills. Objective evidence for a "learning curve" suggests that surgical residents acquire a major portion of their laparoscopic skill between year 1 and year 3 of training.

Palmprint and hand shape, as two kinds of important biometric characteristics, have been widely studied and applied to human identity recognition. The existing research is based mainly on 2D images, which lose the third-dimensional information. The biological features extracted from 2D images are distorted by pressure and rolling, so the subsequent feature matching and recognition are inaccurate. This paper presents a method to acquire accurate 3D shapes of palmprint and hand by projecting full-field composite color sinusoidal fringe patterns and the corresponding color texture information. A 3D imaging system is designed to capture and process the full-field composite color fringe patterns on hand surface. Composite color fringe patterns having the optimum three fringe numbers are generated by software and projected onto the surface of human hand by a digital light processing projector. From another viewpoint, a color CCD camera captures the deformed fringe patterns and saves them for postprocessing. After compensating for the cross talk and chromatic aberration between color channels, three fringe patterns are extracted from three color channels of a captured composite color image. Wrapped phase information can be calculated from the sinusoidal fringe patterns with high precision. At the same time, the absolute phase of each pixel is determined by the optimum three-fringe selection method. After building up the relationship between absolute phase map and 3D shape data, the 3D palmprint and hand are obtained. Color texture information can be directly captured or demodulated from the captured composite fringe pattern images. Experimental results show that the proposed method and system can yield accurate 3D shape and color texture information of the palmprint and hand shape.

Even though surface morphology is always taken into account when assessing clinically pigmented skin lesions, it is not captured by most modern imaging systems using digital imaging. Our aim is to develop a novel three-dimensional (3D) imaging technique to record detailed information of the surface anatomy of melanocytic lesions that will enable improved classification through digital imaging. The apparatus consists of three high-resolution cameras, a light source, and accompanying software. Volume measurements of specific phantoms using volumetric tubes render slightly lower values than those obtained by our 3D imaging system (mean%± SD, 3.8%± 0.98, P<0.05). To examine the reproducibility of the method, sequential imaging of melanocytic lesions is carried out. The mean%± SD differences of area, major axis length, volume, and maximum height are 2.1%± 1.1, 0.9%± 0.8, 3.8%± 2.9, and 2.5%± 3.5, respectively. Thirty melanocytic lesions are assessed, including common and dysplastic nevi and melanomas. There is a significant difference between nevi and melanomas in terms of variance in height and boundary asymmetry (P<0.001). Moreover, dysplastic nevi have significantly higher variances in pigment density values than common nevi (P<0.001). Preliminary data suggest that our instrument has great potential in the evaluation of the melanocytic lesions. However, these findings should be confirmed in larger-scale studies.

In this paper, we present a relatively simple method to acquire a 3D image based on an electrically controlled liquid crystal (LC) lens. Its advantage is that this proposed method does not need any mechanical movements to acquire a 3D image. The tunable-focus LC lens combined with a high-resistance layer (PEDOT) is applied by an overdrive method to become a key optical component for use in a 3D imaging system. Multiple 2D images of slightly different perspectives are recorded, respectively, and 3D images, according to a proposed mapping and projection method, can be reconstructed. This is the first report, to the best of our knowledge, on using an LC lens to reconstruct 3D images. The proposed 3D imaging system is novel for its compact and smart features, so it is attractive for some compact 3D imaging systems.

Metasurface has drawn extensive attention due to its capability of modulating light with a high degree of freedom through ultrathin and sub-wavelength optical elements, and metalens, as one of its important applications, promises to replace the bulky refractive optics, facilitating the imaging system light-weight and compact characteristics. Besides, computer-generated holography (CGH) is of substantial interest for three-dimensional (3D) imaging technology by virtue of its ability of restoring the whole optical wave field and re-constructing the true 3D scene. Consequently, the combination of metalens and CGH holds transformative potential in enabling the miniaturization of 3D imaging systems. However, its imaging performance is subject to the aberrations and speckle noises originating from the metalens and CGH. Inspired by recent progress that computational imaging can be applied to close the gap, a novel full-color imaging system, adopting end-to-end joint optimization of metalens and CGH for high imaging quality, is proposed in this paper. The U-net based network as the pre-processing adjusts weights to make the holographic reconstruction offset imaging defects, incorporating the imaging processing into the step of generating hologram. Optimized by deep learning, the proposed imaging system is capable of full-color imaging with high fidelity in a compact form factor, envisioned to take an essential step towards the high-performance miniaturized imaging system.