Image Projection Research Articles

Accurate and flexible calibration method for a 3D microscopic structured light system with telecentric imaging and Scheimpflug projection.

3D imaging and metrology of complex micro-structures is a critical task for precision manufacturing and inspection. In this paper, an accurate and flexible calibration method for 3D microscopic structured light system with telecentric imaging and Scheimpflug projector is proposed. Firstly, a fringe projection 3D microscopy (FP-3DM) system consisting of a telecentric camera and a Scheimpflug projector is developed, which can take full advantage of the depth of field (DOF) and increase the measurement depth range. Secondly, an accurate and flexible joint calibration method is proposed to calibrate the developed system, which utilizes the established pinhole imaging model and Scheimpflug distortion model to calibrate telecentric imaging, and fully considers the correction and error optimization of the Scheimpflug projection model. Meanwhile, the optimized local homography is calculated to obtain more accurate sub-pixel correspondence between the camera and the projector, and the perspective-n-point (PnP) method make the 3D coordinate estimation of the feature point more accurate. Finally, a prototype and a dedicated calibration program are developed to realize high-resolution and high-precision 3D imaging. The experimental results demonstrate that the re-projection error is less than 1µm, and the 3D repeated measurement error based on feature fitting is less than 4µm, within the calibrated volume of 10(H)mm × 50(W)mm × 40(D)mm.

Spatial Alignment of Organoids Tracking Subclonal Chemotherapy Resistance in Pancreatic and Ampullary Cancer.

Pancreatic and ampullary cancers remain highly morbid diseases for which accurate clinical predictions are needed for precise therapeutic predictions. Patient-derived cancer organoids have been widely adopted; however, prior work has focused on well-level therapeutic sensitivity. To characterize individual oligoclonal units of therapeutic response, we introduce a low-volume screening assay, including an automated alignment algorithm. The oligoclonal growth response was compared against validated markers of response, including well-level viability and markers of single-cell viability. Line-specific sensitivities were compared with clinical outcomes. Automated alignment algorithms were generated to match organoids across time using coordinates across a single projection of Z-stacked images. After screening for baseline size (50 μm) and circularity (>0.4), the match efficiency was found to be optimized by accepting the diffusion thresholded with the root mean standard deviation of 75 μm. Validated well-level viability showed a limited correlation with the mean organoid size (R = 0.408), and a normalized growth assayed by normalized changes in area (R = 0.474) and area (R = 0.486). Subclonal populations were defined by both residual growth and the failure to induce apoptosis and necrosis. For a culture with clinical resistance to gemcitabine and nab-paclitaxel, while a therapeutic challenge induced a robust effect in inhibiting cell growth (GΔ = 1.53), residual oligoclonal populations were able to limit the effect on the ability to induce apoptosis (GΔ = 0.52) and cell necrosis (GΔ = 1.07). Bioengineered approaches are feasible to capture oligoclonal heterogeneity in organotypic cultures, integrating ongoing efforts for utilizing organoids across cancer types as integral biomarkers and in novel therapeutic development.

Adventuring Physics: Integration of Adventure Game and Augmented Reality Based on Android in Physics Learning

One of the difficulties in physics learning is the low motivation to learn because physics materials are considered complex, boring, and abstract for students. Therefore, this research developed an Augmented Reality (AR)-integrated game application "Adventuring Physics" based on android that can create more fun physics learning and provide concept visualization on abstract materials so that they become easier for students to understand. This study aims to develop a valid and practical application of Adventuring Physics games on physics learning. This research uses Research and Development (R&D) design to develop the application. This application has two main features: 'play games' and 'augmented reality'. Furthermore, the game's concept in this application is adapted to the physics materials. Meanwhile, the AR feature in this application can create visualizations in the form of 3D image projections of the material. The results of the validity assessment show that this application is declared valid, feasible, and reliable. In addition, the results of the practicality assessment show that this application is very practical. Thus, the app is worth applying in physics learning. This research has implications as an application of Adventuring Physics that can motivate students to learn physics, apply digital technology in education, and apply it to physics learning.

Optical-visualized photoacoustic tomographic navigation

The current preoperative vascular imaging methods cannot achieve noninvasive high-resolution imaging of deep-localized vessels. Photoacoustic tomography (PAT) can show microvessels with centimeter depth and submillimeter diameter without the use of contrast agents. Combined with PAT and optical projection technology, the Hessian-matrix-based skin removal algorithm and the target matching method were developed to spatially align the photoacoustic data of subcutaneous blood vessels with the anatomy of real patients and to realize three-dimensional (3D) visualization of blood vessels from the body surface. The optical projection navigation system based on PAT has high spatial resolution (∼135 μm) and temporal resolution (0.1 s). In the rabbit injection experiment, 3D distributions of needle and blood vessel (>100 μm) were obtained by image segmentation, which proved that the method can guide micro plastic injection. Furthermore, healthy volunteers' forehead imaging experiments show that 3D visualization and cross-sectional images of the human forehead clearly show the vascular network and ability of the system to image submillimeter blood vessels with penetration depth (∼10.2 mm). Our work confirms that the method of integrated photoacoustic imaging and optical projection has great potential for noninvasive diagnosis and treatment of clinical blood vessels, opening a path for the application of photonics in medical esthetics.

Spatial-Spectral Dual Back-Projection Network for Pansharpening

Deep unfolding networks have obtained satisfactory performance in the pansharpening task owing to their sufficient interpretability. Inspired by the back-projection (BP) mechanism, we propose a BP-driven model, spatial-spectral dual back-project network (S <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> DBPN), to fuse the low spatial resolution multispectral (LR MS) and the high spatial resolution panchromatic (PAN) images by exploiting the BP in spatial and spectral domains. Specifically, the proposed S <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> DBPN is made up of a spatial BP network, a spectral BP network, and a reconstruction network. In the spatial BP network, spatial down- and up-projection modules are derived from BP, which is responsible for the projection of the LR MS image into the spatial domain. By analogy with the spatial BP, we reformulate the degradation between high spatial resolution multispectral (HR MS) and PAN images as spectral down- and up-projections. Then, the spectral BP network is constructed for the projection of the PAN image along the channel dimension. Finally, the features from spatial and spectral BP networks are integrated to produce the desired HR MS image through the reconstruction network. Compared to the state-of-the-art methods, extensive experiments on QuickBird, GeoEye-1, and WorldView-2 datasets demonstrate that our S <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> DBPN produces better HR MS images in terms of qualitative and quantitative evaluation metrics. The code of S <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> DBPN is released at: https://github.com/RSMagneto/S2DBPN.

The Development of Building Information Modelling (BIM) Performance Model forthe Malaysian Construction Industry

The concept of Building Information Modelling (BIM)has attracted greater attention in the Malaysian construction industry since its introduction in 2007. Several projects in Malaysia such as Pusat Kanser Negara and Convocation Hall, UTHM have adopted this concept. One of the benefits of BIM is the projection of a 3D image of the proposed building, which allows stakeholders to get a better idea of the actual building. BIM also improves the planning and design process of the project and thus the quality of the actual building. These advantages of the BIM concept are crucial for the success of the project. Despite the implementation and benefits of BIM, there are still uncertainties about the actual performance of organisations using BIM. This is because there are no evaluation tools or models in Malaysia thatcan evaluate BIM performance of BIM. Therefore, this study aims to develop a performance model for the implementation of BIM in the Malaysian construction industry. In this study, the AHP technique was used to collect data. The AHP results have successfully assigned weights to all BIM performance metrics. The consensus value also exceeds 50%, which confirms that the experts' agreement on the weighting of the metrics is acceptable. In conclusion, the proposed and developed BIM performance model could be useful to practitioners, especially the government and CIDB, in evaluating the performance of BIM organisations in the Malaysian construction industry. These measurement results could be a basis for future improvements for BIM organisations.

SPEAR-Net: Self-Prior Enhanced Artifact Removal Network for Limited-Angle DECT

Dual-energy computed tomography (DECT) is a fully functional instrument for disease detection in clinical practice because of its ability to identify substances and quantify materials. In some practical applications, due to the limitation of scanning conditions, projection data can only be collected from a limited angle, and the consistency of measurement cannot be guaranteed. Existing dual-energy CT reconstruction methods fail to address well the severe artifacts and noise in dual-energy CT images caused by limited-angle scanning. In this paper, we proposed a Self-Prior Enhanced Artifact Removal Network (SPEAR-Net) for limited-angle DECT, which can effectively combine the complementary information in the high- and low-energy domains and self-prior information to contribute positively to the reconstruction of high-quality dual-energy CT images. The SPEAR-Net consists of an image-domain self-prior network(IP-Net), two dual-energy image-domain networks(DIP-Net), and a dual-energy sinogram-domain self-prior network(DSP-Net). Specifically, the IP-Net and DIP-Net are adopted to extract the features of the dual-energy CT reconstructed images under dual-quarter scanning as prior information. The self-prior projection obtained from the forward projection of the prior CT image is harnessed by DSP-Net to complete the dual-energy limited-angle projection data and to facilitate the performance of SPEAR-Net in removing artifacts in the reconstructed dual-energy images. Qualitative and quantitative analyses demonstrate the superior capability of SPEAR-Net in dual-energy limited-angle projection data complementation, detail preservation, and artifact removal. Two popular DECT applications, virtual non-contrast (VNC) imaging and iodine contrast agent quantification, reveal that images reconstructed by SPEAR-Net have promising clinical significance.

Образ Красной Птицы в китайской культуре и фольклоре

The image of the Zhu-niao (Red Bird) is familiar to specialists in the history and mytholo-gy of ancient China. This article examines the origin of the image and the development of the concept of Zhu-niao in Chinese culture and philosophy. The aim of the study is to analyze the semantics and symbolism of the Red Bird image, to establish the difference between the notions of the Red Bird and the Phoenix, to explain the projections of the Red Bird image in Chinese ornamental culture and folklore. The novelty of the study lies in the systematization and generalization of the meanings behind the Red Bird image in Chinese culture. The author concludes that the image of Zhu-niao represents Chinese primitive ancestors’ worship of the totem of the bird, totem of the sun, and totem of the constellation. The semantics of the Red Bird image in Chinese culture and folklore is classified into three categories. The Red Bird is primarily an ornithomor-phic symbol of one of the sides of the world: Zhu-niao (South) is among thefour zoomorphic symbols along with Qing-lun (East), Bai-hu (West), and Xuan-wu (North). The Red Bird is also a symbol of good luck and demonstrates the Chinese people’s idea of praying for good luck. In addition, the image of the Red Bird has become one of the four symbols of Taoism. Although the Red Bird image has different symbolic meanings, its semantics does not go beyond the context of Chinese traditional culture and national psychology. The practical significance of the study lies in the opening up of prospects for research into semantics and symbol-ism of mythical images in Chinese culture. The results of the study can be used in research on Chinese mythological images as well as animal characters in Chinese folklore and literary works.

SPIE-DIR: Self-Prior Information Enhanced Deep Iterative Reconstruction Using Two Complementary Limited-Angle Scans for DECT

Dual-energy computed tomography (DECT) can simultaneously provide the anatomical structure and material-specific information of the scanned object, having many applications in industry and medicine. Different from conventional CT, DECT acquires two attenuation measurements of the same object at two different X-ray spectra, resulting in apparent redundant information. This article exploits this kind of redundancy to develop the self-prior information enhanced deep iterative reconstruction (SPIE-DIR) algorithm for limited-angle DECT. Unlike the routine practice in model-based deep learning (DL) algorithms, the SPIE-DIR method simultaneously performs constraints in the projection, residual, and image domains, corresponding to three modules: projection inpainting, residual correction, and image refinement. During this stage, the prior image and prior projection derived from two complementary limited-angle scans are used to improve the algorithm performance. Besides, to avoid the blurring effect caused by minimizing the Euclidean distance, the Wasserstein generative adversarial network with gradient penalty is adopted to enhance the visual perception of the generated results. Experiments on the simulated data and real rat data have demonstrated that the proposed SPIE-DIR algorithm has the potential to obtain high-quality DECT images from two limited-angle scans. Furthermore, visual and quantitative assessments have shown the promising performance of SPIE-DIR in artifact removal, structural fidelity, CT number preservation, and visual perception enhancement.

Corrections to "Image Projection Network: 3D to 2D Image Segmentation in OCTA Images".

In the above article [1], there is an error in (3). Instead of [Formula: see text] It should be [Formula: see text].

A Fixed-Point Iterative Method for Discrete Tomography Reconstruction Based on Intelligent Optimization

Discrete Tomography (DT) is a technology that uses image projection to reconstruct images. Its reconstruction problem, especially the binary image (0–1 matrix) has attracted strong attention. In this study, a fixed point iterative method of integer programming based on intelligent optimization is proposed to optimize the reconstructed model. The solution process can be divided into two procedures. First, the DT problem is reformulated into a polyhedron judgment problem based on lattice basis reduction. Second, the fixed-point iterative method of Dang and Ye is used to judge whether an integer point exists in the polyhedron of the previous program. All the programs involved in this study are written in MATLAB. The final experimental data show that this method is obviously better than the branch and bound method in terms of computational efficiency, especially in the case of high dimension. The branch and bound method requires more branch operations and takes a long time. It also needs to store a large number of leaf node boundaries and the corresponding consumption matrix, which occupies a large memory space.

Jan Sawka: Theatre of Image and Metaphor

Jan Sawka: Theatre of Image and Metaphor

In Situ Measurement of 2-D Crystal Size Distribution During Cooling Crystallization Process via a Binocular Telecentric Imaging System

In this paper, a novel in-situ measurement method with stereoscopic image analysis is proposed for monitoring crystal length and width distributions during a cooling crystallization process, based on a binocular telecentric imaging system. Firstly, a stereoscopic imaging calibration model is established for using binocular telecentric cameras to conduct in-situ measurement during a cooling crystallization process. Secondly, an enhanced algorithm is presented to improve matching crystal images from binocular image pairs, based on in-situ image preprocessing and segmentation. Thirdly, four key corners related to crystal length and width are determined by using the boundary features of matched crystal image projections. Finally, the length and width of each crystal are computed based on the reconstructed key corners in three-dimensional (3D) coordinate space, by using the established stereoscopic calibration model. Experimental validation on the proposed stereoscopic imaging calibration model and 3D reconstruction of key corners is carried out via in-situ measurement of a microscale checkerboard plate inserted into a cooling crystallizer. In-situ measurements of crystal length and width distributions during the cooling crystallization process of β-form L-glutamic acid are conducted to verify the effectiveness and advantage of the proposed measurement method.

Evaluation of The Impact of Image Projection Methods in Head-up Display on Human Visual Information Processing (Part 2)

Evaluation of The Impact of Image Projection Methods in Head-up Display on Human Visual Information Processing (Part 2)

DIP-QGA: a secure and robust watermarking technique based on direct image projection and quantum genetic algorithm

DIP-QGA: a secure and robust watermarking technique based on direct image projection and quantum genetic algorithm

Bistatic SAR Maritime Ship Target 3-D Image Reconstruction Method Without Distortion in Local Cartesian Coordinate

Bistatic synthetic aperture radar (BiSAR) has been attracting worldwide attention because of its forward-looking imaging and high anti-interference. In harsh environment, it is vital for BiSAR to conduct extensive surveillance, imaging, and recognition of maritime ship targets. However, under the disturbance of sea waves, the ship target has an unknown and massive three-dimensional (3-D) rotation, so that its imaging projection plane (IPP) is also undetermined. Thus, high-dimensional random distortion appears in imaging results, making it difficult to recognize the target through two-dimensional distorted images effectively. To solve these problems, bistatic SAR maritime ship target 3-D image reconstruction method without distortion in local Cartesian coordinate (LCC) is proposed. In this paper, according to positions of scatterers and rotation parameters, significant differences of different scatterers of maritime ship targets have been found in bistatic range, Doppler centroid (DC), and Doppler frequency rate (DFR), which lays a solid foundation for the scatterer separation of ship targets. On this basis, a 3-D R-DC-DFR domain is constructed, and 2-D echoes of the maritime ship target are projected into R-DC-DFR domain to separate scatterers. Then, by remapping data of transmitter and receiver in R-DC-DFR domain to LCC, as well as evaluating their similarity metric, the optimal rotation parameters of the ship target can be obtained via the maximal similarity. Therefore, the image distortion caused by the unknown IPP has been removed, and 3-D image reconstruction of ship targets can be realized without distortion in the LCC. Furthermore, to evaluate performances of 3-D image reconstruction for different rotation parameters and bistatic configurations, 3-D reconstruction index is proposed and analyzed. Both point-targets and maritime ship targets are simulated to emphasize the effectiveness of the proposed method.

Thermoelectric Material Fabrication using Mask Image Projection Based Stereolithography Integrated with Hot Pressing

Abstract: Waste energy harvest using thermoelectric (TE) materials will be a potential solution to the serious environmental pollution and energy shortage problems. Due to limitations of current manufacturing techniques in geometry complexity and high density, TE devices are not widely utilized in daily life to gather waste energy. 3D printing brings an opportunity to solve the fabrication limitations. In this paper, a hybrid process was developed to fabricate thermoelectric materials by integrating hot pressing with stereolithography. The mold and punch were designed and printed to fabricate thermoelectric devices used on hot water tubes via stereolithography. The Sb2Te3 powders filled the 3D printed mold in a layered manner, and each layer of powders was compacted under the pressing of punch at a certain temperature and compressive force. The polymer mold was removed after the sintering process to form the final TE components. A series of experiments were conducted to identify the optimal heating temperature and compressive force. The microstructures morphology and electrical conductivity of fabricated Sb2Te3 samples were evaluated. This research work conducted a scientific investigation into the fabrication of TE material with a hybrid process, including hot pressing and 3D printing, to solve the current manufacturing challenges, providing perspectives on developments of TE devices used in various energy harvest applications.

SIFT-CNN Pipeline in Livestock Management: A Drone Image Stitching Algorithm

Images taken by drones often must be preprocessed and stitched together due to the inherent noise, narrow imaging breadth, flying height, and angle of view. Conventional UAV feature-based image stitching techniques significantly rely on the quality of feature identification, made possible by image pixels, which frequently fail to stitch together images with few features or low resolution. Furthermore, later approaches were developed to eliminate the issues with conventional methods by using the deep learning-based stitching technique to collect the general attributes of remote sensing images before they were stitched. However, since the images have empty backgrounds classified as stitched points, it is challenging to distinguish livestock in a grazing area. Consequently, less information can be inferred from the surveillance data. This study provides a four-stage object-based image stitching technique that, before stitching, removes the background’s space and classifies images in the grazing field. In the first stage, the drone-based image sequence of the livestock on the grazing field is preprocessed. In the second stage, the images of the cattle on the grazing field are classified to eliminate the empty spaces or backgrounds. The third stage uses the improved SIFT to detect the feature points of the classified images to o8btain the feature point descriptor. Lastly, the stitching area is computed using the image projection transformation.

ILEE: Algorithms and toolbox for unguided and accurate quantitative analysis of cytoskeletal images.

The eukaryotic cytoskeleton plays essential roles in cell signaling and trafficking, broadly associated with immunity and diseases in humans and plants. To date, most studies describing cytoskeleton dynamics and function rely on qualitative/quantitative analyses of cytoskeletal images. While state-of-the-art, these approaches face general challenges: the diversity among filaments causes considerable inaccuracy, and the widely adopted image projection leads to bias and information loss. To solve these issues, we developed the Implicit Laplacian of Enhanced Edge (ILEE), an unguided, high-performance approach for 2D/3D-based quantification of cytoskeletal status and organization. Using ILEE, we constructed a Python library to enable automated cytoskeletal image analysis, providing biologically interpretable indices measuring the density, bundling, segmentation, branching, and directionality of the cytoskeleton. Our data demonstrated that ILEE resolves the defects of traditional approaches, enables the detection of novel cytoskeletal features, and yields data with superior accuracy, stability, and robustness. The ILEE toolbox is available for public use through PyPI and Google Colab.

SCREEN ENTELECHY: SURFACE AND PLANE

As part of the modern discourse on screen art, the article examines the phenomenon of a display surface, which represents the boundary between the screen and real spaces. The relevance of this topic is concerned with the development of the technical base, owing to which the variety of screen types is considerable. In everyday life a few decades ago, the screen as an electronic device was primarily associated with a television receiver, whereas today, the methods of modeling visual reality are becoming more complicated, and various screens of mobile devices are increasingly used. It is noteworthy that in practice the inclusion of a display surface directly into the mise-en-scene being filmed has become widespread. The article discusses this kind of creative solution when creating the material; in particular, it substantiates and proposes the concept of "substitution technique", used in the filming process and which assumes the presence of a mobile device screen in the frame, for the introduction into scientific circulation. At the same time, the researcher's attention is directed to the study of the properties of the screen as a reflective surface in the cinema hall, and the surface of the screen of a monitor or a smartphone that emits a light flux. The author takes into account the physical patterns of the screen: the shape and structure of its surface, and also considers screen space. The study analyses the nature of a multi-plane screen. Against this background, the study of the multi-image screen and the discussion of the principles of image projection on the facades of architectural structures seem to be significant. The attention is focused on the mirror surface representing the surrounding world. From the perspective of the visual component of the television material, a set of colour spaces is studied in a single colouristic construct, expressed by the technical parameters of the screen itself and the visual information received from it by the recipient. The study of the multi-plane screen structure, as well as the multi-level screen space, is of practical importance, helping to develop relevant methods for presenting video content in the modern media environment. In theoretical terms, it contributes to the formation of a holistic picture when considering the sphere of television, and also provides intermediate results of scientific work, the main direction of which is the study of the figurative structure of the screen space. The publication may be of interest to professionals and a wide range of readers and viewers.