Projective Image Research Articles

A Sparse Capture Light-Field Coding Algorithm Based on Target Pixel Matching for a Multi-Projector-Type Light-Field Display System

The traditional light-field coding algorithm used in a multi-projector-type light-field display system requires sophisticated and complex three-dimensional modeling processes or parallax images obtained through dense capture. Here we propose an algorithm based on target pixel matching, which directly uses parallax images without a complex modeling process, and can achieve a more accurate light-field reconstruction effect under sparse capture conditions. For the lack of capture information caused by sparse capture, this algorithm compares the pixel similarity of the captured images of the same object point on different cameras to accurately determine the real capture information of the object point at different depths, which is recorded as the target pixel, and then the target pixel is encoded according to the lighting path to obtain the correct projector image array (PIA). By comparing the quality of PIAs generated by the traditional light-field coding algorithm and the display effect after loading the PIAs into the actual display system, we proved the effectiveness of the algorithm.

단안 카메라 기반 측위를 위한 터널 내 시설물의 거리 측정

The GNSS signal used for vehicle localization exhibits a shaded area such as a tunnel. To accurately estimate the location in the shaded area, the accumulated position error must be compensated with information obtained from a separate sensor. When a monocular camera is selected as an additional sensor, the process of measuring the relative distance after detecting objects in a tunnel should be performed before using these data as an indicator. This paper presents a modified inverse perspective transformation model that projects image pixels to the plane parallel to the ground. The image pixels are projected to the plane accounting for the distance and the height of the facility in the tunnel. Then, through the transformation model, the distance of the facility in the tunnel can be measured using a single camera sensor. The Samsungsan Tunnel located on National Highway 110 in South Korea was chosen for the experiment. The estimated distance results by the proposed method were compared with the LiDAR measurements obtained real-time time by computing the position errors for the longitudinal and lateral directions, separately. This study demonstrates the possibility of estimating a distance with only a monocular camera for precise positioning even in a tunnel.

A new method for high dynamic range 3D measurement combining adaptive fringe projection and original-inverse fringe projection

For fringe projection profilometry (FPP), high reflections on metal, plastic, and ceramic surfaces cause intensity saturation, resulting in three dimensional (3D) measurement errors. The measurement efficiency using the multiple exposure method (MEM) is low and the exposure time is difficult to quantify. The original and inverse fringe projection method (OIFPM) suffers from saturation of the opposite fringes on highly reflective surfaces. The adaptive fringe projection method (AFPM) is still limited by image dynamic range and pixel mapping accuracy. To this end, this paper proposes a new scheme combining OIFPM and AFPM, called the original and inverse adaptive fringe projection method (OIAFPM). Firstly, an adaptive intensity template in the camera coordinate system is generated. Secondly, a pixel mapping between the camera and projector images is established. Thirdly, original and inverse adaptive fringes are generated and projected. Finally, 72 wrapped phase calculation equations are given in detail. Experiments confirm that the 3D measurement employing the proposed OIAFPM is much better than that employing AFPM and OIFPM. Although the 3D measurement employing MEM is similar to that employing OIAFPM, the measurement efficiency employing OIAFPM is much higher than that employing MEM.

An Improved Projector Calibration Method by Phase Mapping Based on Fringe Projection Profilometry.

Aiming at the problem of the low accuracy of projector calibration in a structured light system, an improved projector calibration method is proposed in this paper. One of the key ideas is to estimate the sub-pixel coordinates in the projector image plane using local random sample consensus (RANSAC). A bundle adjustment (BA) algorithm is adopted to optimize the calibration parameters to further improve the accuracy and robustness of the projector calibration. After system calibration and epipolar rectification, the mapping relationship between the pixel coordinates and the absolute phase in the projector image plane is established by using cubic polynomial fitting, and the disparity is rapidly solved by using the mapping relationship, which not only ensures the measurement accuracy, but also improves the measurement efficiency. The experimental results demonstrated that the average re-projection error after optimization is reduced to 0.03 pixels, and the proposed method is suitable for high-speed 3D reconstruction without the time-consuming homogenous point searching.

Real-time Navigation for Vascularized Lymph-node Transplantation Using Projection Mapping with Indocyanine Green Fluorescence.

The medical imaging projection system (MIPS) is a real-time surgical navigation device using indocyanine green (ICG) emission signals and active projection mapping. The difference between the object and the projected image is within 1 mm, and the time lag is within 0.1 seconds. We herein report the application of the MIPS to vascularized lymph-node transplantation (VLNT) surgery for lower extremity lymphedema to detect inguinal lymph nodes and perform color-coded navigation surgery for lymph-node resection. A left superficial inguinal lymph node was planned to be used as a donor for VLNT to the right lower leg in a 73-year-old woman with lower extremity lymphedema. Under general anesthesia, multiple intradermal injections of 0.1 ml of ICG were administered around the left inguinal donor site. The MIPS showed a clear linear projection image from a lateral injected point connecting to a lateral superficial inguinal lymph node. The left superficial circumflex iliac artery and vein were dissected for vascularized VLNT. Intraoperative real-time MIPS navigation continuously guided the transection plane colored by ICG fluorescence signals without shifting the visual focus from the surgical field. This is the first report of the intraoperative use of ICG projection mapping for VLNT donor-site surgery. The MIPS was able to visualize functional lymph nodes to facilitate minimally invasive donor-site surgery.

Проекционные образы в театре: режимы (медиа)присутствия

The article examines the phenomenon of (media)presence as a projectional embodiment of objects in theatre. The aim is to describe techniques of using projectional surfaces and devices in performances, using as material Western European productions of the 2000s and 2010s. We attempt to identify and elucidate the modes of presence through the use of projectional images in theatre. The theoretical and methodological framework employed in the article includes a set of ideas at the intersection of theatre, visual, and media studies. Such a framework makes it possible to define performance as a visual event — the act of looking, and to shift the focus from technological artifacts to the processes of mediation of presence by projectional images. We introduce the concept of “(media)presence” as relevant for a productive description of the phenomenon. (Media)presence is the effect of being in the perceptual field of objects of perception, when their physical absence is compensated for by the presence of their screen substitutes. The use of projectional technologies in theatre allows one to achieve the effect of (media)presence through mediation of “life” performances. The ways in which directors utilize projectional surfaces and devices activate several modes of performative embodiment of perceptional objects through projectional images: “absent”, “composite” and “augmented” (media)presence. The text offers a complex analysis of practices of using projectional images in contemporary theatre aimed at achieving the effect of (media)presence.

Homography Estimation Using Marker Projection Control: A Case of Calibration-Free Projection Mapping

Homography transformation, or planar projective transformation, between camera and projector images, which can be estimated by observing four or more pairs of corresponding points between two images, plays a crucial role in dynamic projection mapping with an uncalibrated projector-camera pair. This study discusses a case of dynamic projection mapping onto a moving textured surface where the point correspondence is provided through an actively controlled (not static) marker pattern projection by the projector along with the movement of the surface. Qualitative advantages are discussed in terms of system implementation, the image processing algorithm, and artifact perception by human observers. In addition, a quantitative analysis of alignment errors in the projection mapping is presented to show the effectiveness of the active control of marker patterns.

Architecture as Images: Using Collage as Space Construction Method

This study deconstruct architecture as images, using collages as a method of constructing space. It argues that architecture based on images perceives space as an overlapping and multi-layered fragment of spatial and material elements. This study is conducted through a case study by analysing six collage images of utopian architectural projects, breaking down layers that overlaps and constructed the images. The findings in this study demonstrate how space have different narrative meanings, which appear as foreground-background layers. The foreground layers appear as the main argument that has a larger scale which is positioned as the top layer, while the background layers appear on a smaller scale and are positioned as supporting elements. The study concludes that these findings can be used as a method in architectural design to create a meaningful narrative of space that exist in smaller diverse parts rather than as a generic whole.

Molecular mechanisms of lesion-induced axonal sprouting in the corticofugal projection: the role of glial cells.

Molecular mechanisms of lesion-induced axonal sprouting in the corticofugal projection: the role of glial cells.

A dataset of UAV visible light images of Tianshan spruces for deep learning training in 2017

This dataset is a collection of UAV visible light images of Tianshan spruces (superior mountain forest tree species in Xinjiang) for deep learning training. Tianshan spruces are the most important conifer species in ecological function in Tianshan region, Xinjiang. It is particularly important to effectively identify and divide Tianshan spruce forest through remote sensing technology, which provides important support for collecting the information of Tianshan spruce single factors. In this study, combining with mountain terrain and environmental factors, we developed a UAV field operation plan to collect visible light remote sensing image data of Nanshan Practice Forest Farm of Xinjiang Agricultural University, which were spliced into orthophographic projective images after data filtering, geometric correction and ortho correction and other pre-processing methods. We then adopted Labelme software to plot and classify Tianshan spruces and obtained a dataset of 1,128 UAV visible light images of Tianshan spruces for deep learning training in 2017.

Geometric Parameter Self-Calibration Based on Projection Feature Matching for X-Ray Nanotomography

The mismatch of geometric parameters in a nanotomography system bears a significant impact on the reconstructed images. Moreover, projection image noise is increased due to limitations of the X-ray power source. The accuracy of the existing self-calibration method, which uses only the grayscale information of the projected image, is easily affected by noise and leads to reduced accuracy. This paper proposes a geometric parameter self-calibration method based on feature matching of mirror projection images. Firstly, the fast extraction and matching feature points in the mirror projection image are performed by speeded-up robust features (SURF). The feature triangle is then designed according to the stable position of the system’s rotation axis to further filter the feature points. In turn, the influence of the mismatched points on the calculation accuracy is reduced. Finally, the straight line where the rotation axis is located is fitted by the midpoint coordinates of the filtered feature points, thereby realizing geometric parameter calibration of the system. Simulation and actual data from the experimental results show that the proposed method effectively realizes the calibration of geometric parameters, and the blurring and ghosting caused by geometric artifacts are corrected. Compared with existing methods, the image clarity can be improved by up to 14.4%.

Analysis of Image Fusion Effect in Image Quality of Kidney Stone

Kidney stones are a disease due to the buildup of substances that are not needed in the urinary system. Knowledge of the composition and type of stone is required in the treatment of action. Micro CT is one of the modalities that can be used in determining the composition of kidney stones. However, there are limitations when using single-energy micro-CT. Stone attenuation has almost the same value when using single energy, therefore it is necessary to use dual-energy CT to determine the difference in stone attenuation more precisely. The image of the dual-energy CT micro-energy stone needs to be processed before analyzing and determining the rock composition. Image fusion is one of the image processing techniques that can be used. The purpose of this study was to determine the effect of image fusion on the image quality of five kidney stones. The stages in the research carried out are collecting high energy and low energy projection image data, and performing image fusion on the two projected image data. The results obtained are first, the dual-energy CT image fusion affects the image quality which can be seen from the increase in the signal to noise ratio (SNR) value. A high SNR value provides the best image quality information

Machine Learning for Aiding Blood Flow Velocity Estimation Based on Angiography.

Computational fluid dynamics (CFD) is widely employed to predict hemodynamic characteristics in arterial models, while not friendly to clinical applications due to the complexity of numerical simulations. Alternatively, this work proposed a framework to estimate hemodynamics in vessels based on angiography images using machine learning (ML) algorithms. First, the iodine contrast perfusion in blood was mimicked by a flow of dye diffusing into water in the experimentally validated CFD modeling. The generated projective images from simulations imitated the counterpart of light passing through the flow field as an analogy of X-ray imaging. Thus, the CFD simulation provides both the ground truth velocity field and projective images of dye flow patterns. The rough velocity field was estimated using the optical flow method (OFM) based on 53 projective images. ML training with least absolute shrinkage, selection operator and convolutional neural network was conducted with CFD velocity data as the ground truth and OFM velocity estimation as the input. The performance of each model was evaluated based on mean absolute error and mean squared error, where all models achieved or surpassed the criteria of 3 × 10-3 and 5 × 10-7 m/s, respectively, with a standard deviation less than 1 × 10-6 m/s. Finally, the interpretable regression and ML models were validated with over 613 image sets. The validation results showed that the employed ML model significantly reduced the error rate from 53.5% to 2.5% on average for the v-velocity estimation in comparison with CFD. The ML framework provided an alternative pathway to support clinical diagnosis by predicting hemodynamic information with high efficiency and accuracy.

The affordances of art for making technologies.

With this inaugural lecture as Socrates Professor on the topic of Making Humane Technologies, I aim to show that artistic practices afford embedding technologies better in society. Analyzing artworks made at RAAAF, an art collective that makes visual art and experimental architecture, I will describe three aspects of making practices that may contribute to improving the embedding of technology in society: (1) the skill of working with layers of meaning; (2) the skill of creating material playgrounds that afford free exploration of the potential of new technologies and artistic experiments; and (3) the skill of openness to the possibility of having radically different socio-material practices. I will use images of several RAAAF projects to make these skills involved in making more tangible. It is artistic skills like these that can contribute to a better societal embedding of technologies.

Asymptotic lines on real Milnor links of a family that realizes any genus

We describe the global foliation of asymptotic lines on compact surfaces of genus greater than one, defined in R4 as the links of the real part of the Milnor fibration of a family of polynomials. Through this analysis, we present a description of the global foliation of lines of curvature of the embeddings, defined as the images of the stereographic projection of these links into R3.

“Digital Leviathan”: Scenarios for the Development of the Hobbesian Monster in the 21st Century

In the research, the Hobbesian concept of “Leviathan” is used as a metaphor and a “heuristic scheme” describing the change of epochs and the formation of a new universal scale for innovative forms of socio-political organization. The subject of the research is the phenomenon of digitalization, as well as key changes caused by the digital transformation of public policy and power relations. “Digitalization” is considered as an ambiguous and multilevel phenomenon, reflecting a whole series of cardinal transformations in the sociopolitical life of society, which at the ideological, institutional, instrumental, technological and praxiological levels “clears space” for new forms of social organization. Аrgues that currently there is an acute competition to define, legitimize and promote a certain “projective image of the future” corresponding to the latest socio-political order and normative sociotechnological system (“engineering law”). In particular, the author considers contradictory trends, on the one hand, aimed at preserving and reproducing traditional political institutions, and on the other, related to forming new digital era institutions, digital governance structures and practices of public-power interactions. The research pays special attention to the competition of the state and new digital and technological actors in the political space. It discusses various scenarios of digital transformation of society, state, and government and considers such digital effects in the modern political process as “information noise”, “information overload”, “profile reconfigurations” of relations, the formation of alternative digital spaces (metaverses), as well as their influence on the current political order, power relations, socio-political dynamics.

The Women of Chicago Public Housing. Architects of their Own ‘Homeplace’

The story of public housing in Chicago, and the rest of the United States for that matter, tends to fixate on negative images of housing projects built between c. 1940-1960, like Cabrini-Green or Wentworth Gardens. Now that so many of the buildings have been demolished (or “redeveloped”) and scholars, institutions, and the general public have begun to untangle the complexity of the history of public housing in the U.S., it is time to move beyond the damaging narratives and negative imagery to better understand how women persevered and adapted to ensure they and their families not only had basic needs met, but also had access to safe spaces, key facilities, and opportunities for community-building, joy, and pride in their home. This paper explores connections between issues of architecture and the impact of women on the design and reform of Cabrini-Green, Wentworth Gardens, and other key examples, to demonstrate how women residents helped shape the built environment of public housing in Chicago through organizing, activism, and the appropriation of space based on everyday needs and use. Through an analysis of photographs documenting the interiors of Cabrini-Green and using a theoretical framework that combines feminist theorist bell hooks’ notion of the ‘homeplace’ as a ‘site of resistance’ (1990) with architectural historian Dell Upton’s concept of the ‘cultural landscape’ (1991), this paper proposes that we modify our current definition of an “Architect” and in fact consider these public housing residents ‘architects of their own homeplace’.

COLOR-INFORMATION TECHNOLOGIES AS A COMPONENT OF BRAND-COLORISTIC OF SEWING PRODUCTS

The article is devoted to solving the task of analyzing the essence, features, and rules of brand coloristic as a tool for influencing the target audience of a fashion brand. The authors proposed approaches to using mobile applications as color information technologies to develop brand coloristic of the projected image of a clothing model. As a result of the conducted research, a color design strategy for fashion brand garments was developed. The essence of a comprehensive study of color perception: its theory and practice, personalities, institutions, semantics, and the use of color information technologies for developing brand coloristic of the projected image of a clothing model is substantiated. The interaction of color in art, design, advertising, and science has been proven. Based on consumers’ physiological, emotional, intellectual, and behavioral reactions to color, a comprehensive system, “The meaning of color,” is proposed. The motives and behavioral mechanisms of consumers in the fashion industry have been studied, and the factors affecting the purchase decision have been determined. This made it possible to represent the information model of the reaction to the garment, as a component of the clothing color design strategy, by including subsets of stimuli and emotions in the design-projection process. The main rules of modern brand coloristic were analyzed and applied using modern color information technologies in the form of a ready-made Color Gear mobile application. The proposed process of using current color and information technologies to harmonize the graphic fashion image allows you to get an individual coordinated project image with a planned impression. Thus, it has been proven that the elements of brand color are an essential factor that affects the consumer’s perception of fashion brands and, as a result, sales and profits. Broad prospects for further development of the author’s mobile application for harmonizing clothing colors have been revealed, especially when it comes to finding a new color project image because the competition of fashion brands is active and demanding at the current stage.

INNOVATIVE TECHNOLOGIES FOR DECORATING LIGHT INDUSTRY PRODUCTS

The article is devoted to the solution of the task of forming project images in modern mass fashion in the context of the use of innovative decoration technologies on the example of designing an author’s collection of women’s clothing. The scientific novelty of the study consists of the analysis and systematization of creative and innovative decoration technologies with the aim of further integration into the fashion design of clothing. The study’s practical significance lies in the study of characteristic techniques and elements of innovative clothing decoration. The article describes the stages and provides recommendations for producing the author’s prints for decorating products of the author’s collection. The authors focused on developing the author’s print using computer technologies in universal graphic reactors of both raster and vector graphics for further thermal transfer printing. The study demonstrates the process of forming a sketch of a fashionable design image using an information model, which allows authors to present it as a single symbolic system using modern practices of visual presentation of trendy innovations. The products in the collection are made of different materials, which, when combined into sets, give the image of unusualness and sophistication. The collection was developed in the format of the Pop Art style using fashion trends. The authors defined and thought out the main images, forms, and constituent elements of the designed products of the author’s collection sets. When creating clothing models, special attention was paid to the originality and multifunctionality of the collection’s products and their parts. The creative and design, constructive, and technological solutions of models of sets of the author’s collection were produced and presented at the All-Ukrainian competition of young designers “Colours of Podillia” (Khmelnytskyi, KhNU, 2022), were developed.

Feature detection network-based correction method for accurate nano-tomography reconstruction.

Driven by the development of advanced x-ray optics such as Fresnel zone plates, nano-resolution full-field transmission x-ray microscopy (Nano-CT) has become a powerful technique for the non-destructive volumetric inspection of objects and has long been developed at different synchrotron radiation facilities. However, Nano-CT data are often associated with random sample jitter because of the drift or radial/axial error motion of the rotation stage during measurement. Without a proper sample jitter correction process prior to reconstruction, the use of Nano-CT in providing accurate 3D structure information for samples is almost impossible. In this paper, to realize accurate 3D reconstruction for Nano-CT, a correction method based on a feature detection neural network, which can automatically extract target features from a projective image and precisely correct sample jitter errors, is proposed, thereby resulting in high-quality nanoscale 3D reconstruction. Compared with other feature detection methods, even if the target feature is overlapped by other high-density materials or impurities, the proposed Nano-CT correction method still acquires sub-pixel accuracy in geometrical correction and is more suitable for Nano-CT reconstruction because of its universal and faster correction speed. The simulated and experimental datasets demonstrated the reliability and validity of the proposed Nano-CT correction method.