Stitching Process Research Articles

Generative Design for Textiles: Opportunities and Challenges for Entertainment AI

This paper reports on two generative systems that work in the domain of textiles: the Hoopla system that generates patterns for embroidery samplers, and the Foundry system that creates foundation paper piecing patterns for quilts. Generated patterns are enacted and interpreted by the human who stitches the final product, following a long and laborious, yet entertaining and leisurely, process of stitching and sewing. The blending of digital and physical spaces, the tension between machine and human authorship, and the juxtaposition of stereotypically masculine computing with highly feminine textile crafts, leads to the opportunity for new kinds of tools, experiences, and artworks. This paper argues for the values of textiles as a domain for generative methods research, and discusses generalizable research problems that are highlighted through operating in this new domain.

Panoramic Imaging Assessment of Different Bladder Phantoms – An Evaluation Study

ObjectiveTo evaluate “panoramic image stitching” for cystoscopy, a novel technique to augment a urologist's field of view transoperatively in real-time during a cystoscopic “keyhole” procedure, 3-D bladder phantoms provide a suitable setting. Thus, the objective is the evaluation of different 3-D printed bladder phantoms with respect to their ability to be used for extended experiments of panoramic cystoscopy. Materials and MethodsFive bladder phantoms with different geometries, surface textures, stiffness and materials were assessed with rigid 0- and 30-degree lenses and a video-cystoscope regarding suitability for image stitching. For panoramic image generation, we use an established real-time stitching approach successfully applied to retrospective cystoscopy image sequences from real clinical cases. For evaluation of the experiments two quality criteria were defined, namely ‘completeness’ (describing the internal area of the phantom that can be stitched), and ‘extension’ (how far does an acquired panorama extend beyond the assumed ‘equator’ of the phantom). ResultsPanoramas of all phantom and endoscope combinations were computed. Using landmarks (south pole, north pole, equator) in the phantoms, maximum extension of the panoramas was assessed. The computed panoramas yield maximum extensions between 270o (0-degree cystoscope) and 330o (video cystoscope). Deformable phantoms yield larger panoramas than the rigid models. ConclusionIn can be concluded that the stitching process works quite well with all evaluated phantoms. Nevertheless, a novel phantom would be needed, combing a deformable, elliptical geometry and real-type vascular texture in the inside, that can be filled with water.

Content-Preserving Image Stitching With Piecewise Rectangular Boundary Constraints.

This article proposes an approach to content-preserving image stitching with regular boundary constraints, which aims to stitch multiple images to generate a panoramic image with piecewise rectangular boundaries. Existing methods treat image stitching and rectangling as two separate steps, which may result in suboptimal results as the stitching process is not aware of the further warping needs for rectangling. We address these limitations by formulating image stitching with regular boundaries in a unified optimization framework. Starting from the initial stitching result produced by traditional warping-based optimization, we obtain the irregular boundary from the warped meshes by polygon Boolean operations which robustly handle arbitrary mesh compositions. By analyzing the irregular boundary, we construct a piecewise rectangular boundary. Based on this, we further incorporate line and regular boundary preservation constraints into the image stitching framework, and conduct iterative optimizations to obtain an optimal piecewise rectangular boundary. Thus we can make the boundary of the stitching result as close as possible to a rectangle, while reducing unwanted distortions. We further extend our method to video stitching, by integrating the temporal coherence into the optimization. Experiments show that our method efficiently produces visually pleasing panoramas with regular boundaries and unnoticeable distortions.

Improvement of a Stitching Operation in the Stitching Linear-Scan Method for Measurement of Cylinders in a Small Dimension

Attempts are made in this paper to improve the quality of the stitching between adjacent arc-profiles in the stitching linear-scan method for the roundness measurement of a cylinder in a small dimension. The data in the edge region of an arc-profile, which could be influenced by the pressure angle of the measurement probe of a linear-scan stylus profiler, are eliminated in the stitching process to improve the quality of stitching. The effectiveness of the elimination of the edge region of an arc-profile is evaluated by employing the cross-correlation coefficient of two adjacent arc-profiles as an evaluation index. Furthermore, a modification is made to the experimental setup to reduce the misalignment of a workpiece along its axial direction with respect to the scanning probe. Experiments are carried out by using the modified setup to demonstrate the feasibility of the stitching linear-scan method for the roundness measurement of a small cylinder, which is difficult to measure by the conventional rotary-scan method.

Interfacial Failure in Stitched Foam Sandwich Composites.

In this paper, the use of a customized automatic reinforcement stitching equipment was demonstrated. The stitching of foam sandwich composite preforms was achieved to obtain structures with improved interfacial properties. The effect of different stitching spacings on the crack propagation process in glass fiber reinforced plastics (GFRP)/foam sandwich composite interfaces was examined by Mode-I Cracked Sandwich Beam (CSB) fracture tests. The load–displacement curve, the crack propagation process, and the release rate of critical strain energy were analyzed. The CSB fracture test results show that the stitching treatment with different stitching spacings increase the peak load and fracture displacement. Furthermore, it was found that the mechanism of crack propagation is changed by the stitching process. The release rates of the critical strain energy in specimens with 0- and 10-mm stitch spacings were evenly distributed, with an average of 0.961 kJ/m2 and 1.667 kJ/m2, respectively, while the release rates of critical strain energy in specimens with 6-mm and 8-mm stitch spacings were linearly distributed. The CSB fracture tests confirmed that the best suture spacing was 8 mm. Based on these results, the mechanism of crack propagation and the toughening mechanism of the resin column could be revealed.

Deep Learning-Based Automated Background Removal for Structural Exterior Image Stitching

This paper presents a deep learning-based automated background removal technique for structural exterior image stitching. In order to establish an exterior damage map of a structure using an unmanned aerial vehicle (UAV), a close-up vision scanning is typically required. However, unwanted background objects are often captured within the scanned digital images. Since the unnecessary background objects often cause serious distortion on the image stitching process, they should be removed. In this paper, the automated background removal technique using deep learning-based depth estimation is proposed. Based on the fact that the region of interest has closer working distance than the background ones from the camera, the background region within the digital images can be automatically removed using a deep learning-based depth estimation network. In addition, an optimal digital image selection based on feature matching-based overlap ratio is proposed. The proposed technique is experimentally validated using UAV-scanned digital images acquired from an in-situ high-rise building structure. The validation test results show that the optimal digital images obtained from the proposed technique produce the precise structural exterior map with computational cost reduction of 85.7%, while raw scanned digital images fail to construct the structural exterior map and cause serious stitching distortion.

Research on 3D Reconstruction methods Based on Binocular Structured Light Vision

There are many studies on 3D reconstruction based on monocular vision, but for complex surface parts, contour occlusion problems will occur, which requires binocular or multi-eye vision for 3D reconstruction. This paper mainly uses binocular structured light vision to study 3D reconstruction. The specific methods are: use structured light coding to calibrate the binocular camera, the projector and the left and right cameras to obtain the calibration parameters, and then obtain the 3D coordinates based on the triangulation principle that there is only one intersection between the camera straight line equation and the projector plane equation in space. Because of the binocular structured light used in this article, the point clouds of the left and right cameras need to be merged to complete the stitching process of the two points clouds. Through the verification of this methods, the stitching error is good, and the point cloud can be streamlined later to improve the point cloud registration rate.

The predictive factors that are associated with the number of sutures used during meniscal repair

PurposeTo investigate factors associated with the consumption of a large number of sutures during arthroscopic meniscus repair procedures.MethodsAll patients who received meniscal repair, with or without concomitant anterior cruciate ligament (ACL) reconstruction, in our hospital from January 2015 to December 2019 were included in the current study. Demographic data (sex, age, body mass index (BMI), and injury-to-surgery interval) and surgical data (the site of the tear, side of the meniscus, presence of an ACL rupture or not and the number of sutures) were retrospectively collected from our medical records. The number of sutures was divided into two groups (1–2 sutures versus > 2 sutures). The stitching process was implemented through an all-inside technique using a meniscal repair device (Fast-Fix; Smith & Nephew). According to the length and stability of the meniscal tear, one to seven sutures were used. Univariate analysis consisted of chi-square tests. Multivariate logistic regression was then performed to adjust for confounding factors.ResultsA total of 242 patients, including 168 males and 57 females, was finally included. In the univariate analysis, we found that those patients who underwent meniscus repair within one month after meniscus tear were more likely to need fewer sutures than those who underwent surgery more than one month after injury (70/110 versus 59/115, p=0.062). In total, 75/109 (68.8%) lateral meniscal tears were repaired with fewer sutures than medial (34/72, 47.2%) and bilateral meniscus injuries (20/44, 45.4%; p=0.003). In the multivariate analysis, we found that the duration of injury (OR, 2.06; 95% CI, 1.16–3.64, p=0.013), presence of an ACL injury (OR, 3.76; 95% CI, 1.97–7.21, p< 0.001) and the side of the meniscus (OR, 0.31; 95% CI, 0.14–0.65, p=0.002) were associated with the number of sutures used during meniscal repair procedures.ConclusionsPatients who underwent meniscal repair within one month after meniscus tear, especially lateral menisci tears, were more likely to need fewer sutures.Study designCase-control study; level of evidence, 3.

A Novel Real-Time Virtual 3D Object Composition Method for 360° Video

As highly immersive virtual reality (VR) content, 360° video allows users to observe all viewpoints within the desired direction from the position where the video is recorded. In 360° video content, virtual objects are inserted into recorded real scenes to provide a higher sense of immersion. These techniques are called 3D composition. For a realistic 3D composition in a 360° video, it is important to obtain the internal (focal length) and external (position and rotation) parameters from a 360° camera. Traditional methods estimate the trajectory of a camera by extracting the feature point from the recorded video. However, incorrect results may occur owing to stitching errors from a 360° camera attached to several high-resolution cameras for the stitching process, and a large amount of time is spent on feature tracking owing to the high-resolution of the video. We propose a new method for pre-visualization and 3D composition that overcomes the limitations of existing methods. This system achieves real-time position tracking of the attached camera using a ZED camera and a stereo-vision sensor, and real-time stabilization using a Kalman filter. The proposed system shows high time efficiency and accurate 3D composition.

Panoramic Image Stitching: A Survey

This electronic document is a report on Image Stitching. Image stitching is the process of creating an image panorama from a given set of images that have some common(overlapping) area in them. Previous researches done on this topic show that there is still a lot of scope for improvement in this field as although we are able to achieve good results but we haven’t really been able to achieve perfection. There are a lot of factors that are to be blamed here. While Stitching Images, there could be many challenges such as images being corrupt by noise and/or presence of parallax in the images. Image Stitching process is divided into 5 major steps: Image Registration, Feature Detection, Feature Matching, Homography Estimation and Image Blending. In this document we are going to discuss the current status of image processing techniques and what are the challenges being faced.

A fast and robust real-time surveillance video stitching method

Real-time video stitching can build a wider field of view for surveillance, which faces a compromise between stitching speed and visual quality. A fast and robust real-time surveillance video stitching method is proposed to deal with the ghosting effect caused by moving objects and misalignments caused by background change or slight camera shift through automatic updating. By stitching key frames, parameters such as pix mapping table, stitching seams and blending weights are calculated, and most of subsequent frames are directly blended with CUDA acceleration based on the pre-calculated stitching parameters. Fast and effective algorithms are designed to detect the change of stitching seam and background during the whole stitching process, which determines whether to update the stitching seam or recalculate stitching parameters. Experiments show that this method can robustly and automatically solve the ghosting and misalignments to improve visual quality and achieve satisfactory real-time performance.

Dual subaperture stitching for large flat mirror testing.

The Ritchey-Common test is a widely used method for testing flat mirrors with a larger reference spherical mirror. However, with the increase in the size of the flat mirror, the fabrication of the spherical mirror becomes more time consuming and expensive. In this study, we developed a novel technique to test a large flat mirror with a smaller reference sphere using a dual subaperture stitching (DSS) method. One part of the DSS technique is a modified Ritchey-Common test, which uses a reference sphere smaller than the flat mirror. The other part involves scanning along the centerline of the flat mirror. The former can be used to determine the surface form error (SFE), except for rotationally symmetric components, such as power and spherical aberrations, which can be measured by the latter. To perform the stitching process using a smaller reference sphere, the flat mirror was repeatedly rotated by a fixed angular step. One of the advantages of the rotation of the flat mirror is that it can be used to identify the errors resulting from the reference sphere, which do not vary during the rotation of the flat mirror. We verified the DSS method using a 152 mm diameter optical flat mirror and determined the root-mean-square (rms) measurement error to be only 0.2 nm, which was comparable to the error of the full-aperture interferometric measurement. In addition, we tested a 1.2 m diameter flat mirror with a reference sphere with an aperture of 0.8 m and measured its SFE to be 11.9±0.5nm rms.

Large Gradient Micro-Structure Topography Measurement with Multi-Angle Stitching Digital Holographic Microscope

We present an effective method for the topography characterization of large gradient micro-structure based on digital holographic microscope (DHM). Due to the limitation of numerical aperture of DHM system, high frequency information corresponding to large gradient regions of specimen is prohibited from entering the imaging system and the complete collection of specimen features cannot be implemented. To solve this problem, we use a common configuration of off-axis DHM system to capture the holograms from multiple angles of the sample, and the various object waves coming from the sample of different tilt angle is corrected and spliced into a fully topography by multi-angle stitching process. In this way, the measurement of large gradient topography of specimen can be realized. Experimental results of large gradient microlens demonstrate the practicability and precision of the presented method.

Characterization of mode II specimen using I-fiber Stitching process

The reinforcement of composite structures in the through-thickness direction has been developed through a new stitching process. This reinforcement is called I-fiber stitching process due to the final shape of the reinforced fiber. Following mode I results from a previous research, the present study proposes a mode II analysis in order to define the cohesive parameters through a cohesive law that will allow to predict the behavior of reinforced composite structures under this specific fracture mechanism. Several stitching patterns have been tested with two kinds of dry carbon fiber yarn stitched as reinforcement, the first group with 1 × 6 and 2 × 6 for 6 k yarn and the second group with 1 × 3 and 2 × 3 patterns for 12 k yarn. A parametric study was performed after test a single stitch unit cell specimen for the two carbon fiber yarns to obtain the cohesive parameters that have been used after in a macro-scale model with the reinforced stitching pattern. Using the finite element modeling, the numerical analyses were compared with the test results and have showed a great concordance with the experiments, these results have allowed to fix the stitching parameters through the cohesive law for mode II fracture mechanism.

Real-Time Video Stitching for Mine Surveillance Using a Hybrid Image Registration Method

Video stitching technology provides an effective solution for a wide viewing angle monitoring mode for industrial applications. At present, the observation angle of a single camera is limited, and the monitoring network composed of multiple cameras will have many overlapping images captured. Monitoring surveillance cameras can cause the problems of viewing fatigue and low video utilization rate of involved personnel. In addition, current video stitching technology has poor adaptability and real-time performance. We propose an effective hybrid image feature detection method for fast video stitching of mine surveillance video using the effective information of the surveillance video captured from multiple cameras in the actual conditions in the industrial coal mine. The method integrates the Moravec corner point detection and the scale-invariant feature transform (SIFT) feature extractor. After feature extraction, the nearest neighbor method and the random sampling consistency (RANSAC) algorithm are used to register the video frames. The proposed method reduces the image stitching time and solves the problem of feature re-extraction due to the change of observation angle, thus optimizing the entire video stitching process. The experimental results on the real-world underground mine videos show that the optimized stitching method can stitch videos at a speed of 21 fps, effectively meeting the real-time requirement, while the stitching effect has a good stability and applicability in real-world conditions.

Research on Novel Flexible High-Saturation Nanocrystalline Cores for Wireless Charging Systems of Electric Vehicles

The ferrite core plays an essential role in coupling enhancement and magnetic shielding for the wireless power transfer of electric vehicles. However, ferrite has apparent defects, such as a low saturation and brittleness, especially at the vehicle side. Therefore, a novel flexible nanocrystalline core is proposed in this article, which has high flexibility and high saturation limits. However, the nanocrystalline core has a large eddy current under 85-kHz excitation, so the refinement crushing process and alternating seamless stitching process are adopted to reduce the eddy loss. The feasibility of the improvement process is preliminarily verified via finite element simulations, and four nanocrystalline cores with different permeabilities are obtained. Through static parameter measurements and 7.7-kW loading tests, the modified nanocrystalline cores achieve excellent results. Based on the above, the nanocrystalline core with the best performance is further selected for an anti-saturation test and leakage measurement at 11 kW. Even when the thickness is reduced to 2 mm, the ac-ac efficiency remains 97.408%. The maximum core temperature is only 80.9 °C, and the flux leakage completely satisfies the limit requirements of ICNIRP 2010. In contrast, the ferrite core cannot withstand the impact of a strong alternating field and fails.

Usage of Fusible Sewing Threads to Improve the Waterproof Property of Seam

In classical stitching process, needle holes occur during the penetration of the needle through the fabric. If the waterproofness of the sewn product is important, the water leakage from these holes must be prevented. To prevent this negative situation, different techniques such as sealing of seams with waterproof tapes, joining the textile materials by bonding or welding are used. Among these techniques, there is no needle damage in bonding and welding and all the seam area is covered by thermal or chemical bonding. In sewing technology, the water leakage is prevented by covering all the seam area with seam sealing tape. These three methods have different effects on the physical properties of the seams obtained. Instead of covering the whole seam area, covering just the needle damages is the focus of this research. With this aim, fusible sewing threads were used to cover the needle damages to increase the waterproof performance of seam line. The fusible sewing threads have not been used for obtaining waterproof seams before. In this research, the fusible sewing threads were used as lower thread in different combinations. Initial results of waterproofness test show that, melted fusible threads improve the waterproof performance of seams. In other words, the needle damages on sewn fabric can be covered by melted fusible sewing thread. However, unbalanced seam is the negative side of this research because of using different threads as needle and bobbin thread. Additionally, there is no variety of fusible threads to select an appropriate one for this method. The study is hoped to be a sample for the further studies on this method, using different fusible threads, fabrics, seam types and even improving new fusible threads for this waterproofing method.

IC Microscopic Image Stitching Based on Improved Line Matching

Integrated Circuit(IC) microscopic image stitching is an important process in IC reverse engineering. However, IC is highly integrated and miniaturized, with many similar structures and dense distribution, and the overlapping region of some IC microimages may be the low-texture region. As a result, the traditional image stitching method is prone to mismatch, and the stitching effect is poor. This paper proposes an IC microscopic image stitching method based on improved line matching. The method first extract line segments from two IC microscopic images to be stitched by using Edline algorithm. Secondly, the intersection of line segments is generated by using the position relation of line segments in a certain strategy. Then, combined with the 2D capture method of the IC microscopic image, we limit the matching region. Finally, image registration is completed by combining points and lines, and a transformation matrix is obtained to stitch IC microimages. Experimental results demonstrate that the proposed method reduces the possibility of mismatching in the stitching process while using the stable line features and the position constraints between line segments in IC microscopic images. Moreover, the image stitching guided by line features can also achieve good stitching results in low-texture IC micrograph.

Performance Enhancement of Image Stitching Process Under Bound Energy Aided Feature Matching and Varying Noise Environments

Image mosaicing is a method that combines several images or pictures of the superposing field of view to create a panoramic high-resolution picture. In the field of medical imagery, satellite data, computer vision, military automatic target recognition can be seen the importance of image mosaicing. The present domains of studies in computer vision, computer graphics and photo graphics are image stitching and video stitching. The registration of images includes five primary phases: feature detection and description; matching feature; rejection of outliers; transformation function derivation; image replication. Stitching images from specific scenes is a difficult job when images can be picked up under different noise. In this paper, we examine an algorithm for seamless stitching of images in order to resolve all such problems by employing dehazing methods to the collected images, and before defining image features and bound energy characteristics that match image-based features of the SIFT-Scale Invariant Feature Transform. The proposed method experimentation is compared with the conventional methods of stitching of image using squared distance to match the feature. The proposed seamless stitching technique is assessed on the basis of the metrics, HSGV and VSGV. The analysis of this stitching algorithm aims to minimize the amount of computation time and discrepancies in the final stitched results obtained.

Fast Anchor Point Matching for Emergency UAV Image Stitching Using Position and Pose Information.

With the development of unmanned aerial vehicle (UAV) techniques, UAV images are becoming more widely used. However, as an essential step of UAV image application, the computation of stitching remains time intensive, especially for emergency applications. Addressing this issue, we propose a novel approach to use the position and pose information of UAV images to speed up the process of image stitching, called FUIS (fast UAV image stitching). This stitches images by feature points. However, unlike traditional approaches, our approach rapidly finds several anchor-matches instead of a lot of feature matches to stitch the image. Firstly, from a large number of feature points, we design a method to select a small number of them that are more helpful for stitching as anchor points. Then, a method is proposed to more quickly and accurately match these anchor points, using position and pose information. Experiments show that our method significantly reduces the time consumption compared with the-state-of-art approaches with accuracy guaranteed.