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This paper provides a tutorial and survey for a specific kind of illustrative
visualization technique: feature lines. We examine different feature line
methods. For this, we provide the differential geometry behind these concepts
and adapt this mathematical field to the discrete differential geometry. All
discrete differential geometry terms are ex...
Citations
... This means the anatomical structure can be used to enable a direct link between attribute values and a patient's anatomy. For an overview of illustrative visualization techniques and focus and context depictions, we refer to the surveys of Lawonn et al. [41][42][43]. ...
We propose a visualization application, designed for the exploration of human spine simulation data. Our goal is to support research in biomechanical spine simulation and advance efforts to implement simulation-backed analysis in surgical applications. Biomechanical simulation is a state-of-the-art technique for analyzing load distributions of spinal structures. Through the inclusion of patient-specific data, such simulations may facilitate personalized treatment and customized surgical interventions. Difficulties in spine modelling and simulation can be partly attributed to poor result representation, which may also be a hindrance when introducing such techniques into a clinical environment. Comparisons of measurements across multiple similar anatomical structures and the integration of temporal data make commonly available diagrams and charts insufficient for an intuitive and systematic display of results. Therefore, we facilitate methods such as multiple coordinated views, abstraction and focus and context to display simulation outcomes in a dedicated tool. By linking the result data with patient-specific anatomy, we make relevant parameters tangible for clinicians. Furthermore, we introduce new concepts to show the directions of impact force vectors, which were not accessible before. We integrated our toolset into a spine segmentation and simulation pipeline and evaluated our methods with both surgeons and biomechanical researchers. When comparing our methods against standard representations that are currently in use, we found increases in accuracy and speed in data exploration tasks. In a qualitative review, domain experts deemed the tool highly useful when dealing with simulation result data, which typically combines time-dependent patient movement and the resulting force distributions on spinal structures.
... Van Pelt et al. [vPGL * 14] developed comparative visualization techniques revealing differences in the interplay of blood flow and wall mechanics based on possible stent configurations. For detailed overviews of illustrative and and cut-away techniques, we refer to [LP16,LVPI18,LSBP17]. ...
We present ANEULYSIS, a system to improve risk assessment and treatment
planning of cerebral aneurysms. Aneurysm treatment must be carefully examined as there is a risk of fatal outcome during surgery. Aneurysm growth, rupture, and treatment success depend on the interplay of vascular morphology and hemodynamics. Blood flow simulations can obtain the patient-specific hemodynamics. However, analyzing the time-dependent, multi-attribute data is time-consuming and error-prone. ANEULYSIS supports the analysis and visual exploration of aneurysm data including morphological and hemodynamic attributes. Since this is an interdisciplinary process involving both physicians and fluid mechanics experts, we provide a redundancy-free management of aneurysm data sets according to a consistent structure. Major contributions are an improved analysis of morphological aspects, simultaneous evaluation of wall- and flow-related characteristics as well as multiple attributes on the vessel wall, the assessment of mechanical wall processes as well as an automatic classification of the internal flow behavior. It was designed and evaluated in collaboration with domain experts who confirmed its usefulness and clinical necessity.
... Outlines [17] are commonly used to increase the visibility of 3D shapes [18,19]. Pattern density [10] and overlay opacity [5] also affect how information is perceived. ...
{When visualizing data in a realistically rendered 3D virtual environment, it is often important to represent not only the 3D scene but also overlaid information about additional, abstract data. These overlays must be usefully visible, i.e. be readable enough to convey the information they represent, but remain unobtrusive to avoid cluttering the view. We take a step toward establishing guidelines for designing such overlays by studying the relationship between three different patterns (filled, striped and dotted patterns), two pattern densities, the presence or not of a solid outline, two types of background (blank and with trees), and the opacity of the overlay. For each combination of factors, participants set the faintest and the strongest acceptable opacity values. Results from this first study suggest that i) ranges of acceptable opacities are around 20-70%, that ii) ranges can be extended by 5% by using an outline, and that iii) ranges shift based on features like pattern and density.
... This means the anatomical structure can be used to enable a direct link between attribute values and a patient's anatomy. For an overview of illustrative visualization techniques and focus and context depictions, we refer to the surveys of Lawonn et al. [41][42][43]. ...
We propose a visualization application, designed for the exploration of human spine simulation data. Our goal is to support research in biomechanical spine simulation and advance efforts to implement simulation-backed analysis in surgical applications. Biomechanical simulation is a state-of-the-art technique for analyzing load distributions of spinal structures. Through the inclusion of patient-specific data, such simulations may facilitate personalized treatment and customized surgical interventions. Difficulties in spine modelling and simulation can be partly attributed to poor result representation, which may also be a hindrance when introducing such techniques into a clinical environment. Comparisons of measurements across multiple similar anatomical structures and the integration of temporal data make commonly available diagrams and charts insufficient for an intuitive and systematic display of results. Therefore, we facilitate methods such as multiple coordinated views, abstraction and focus and context to display simulation outcomes in a dedicated tool. By linking the result data with patient-specific anatomy, we make relevant parameters tangible for clinicians. Furthermore, we introduce new concepts to show the directions of impact force vectors, which were not accessible before. We integrated our toolset into a spine segmentation and simulation pipeline and evaluated our methods with both surgeons and biomechanical researchers. When comparing our methods against standard representations that are currently in use, we found increases in accuracy and speed in data exploration tasks. In a qualitative review, domain experts deemed the tool highly useful when dealing with simulation result data, which typically combines time-dependent patient movement and the resulting force distributions on spinal structures.
... Thus, it allows visualization creators to use more visual variables [Ise15], use several layers of information [Ise15;Ise16], reduces clutter and occlusion [BCPV+12], and improves the perception of shape and depth [BCPV+12;Ise15;PBCI+16]. It thus also relies on insights from perception and cognition [BHIM+05;VHE10], ultimately to show the relevant information [BHIM+05], to allow people to better understand what they see [BCPV+12;HWRR+10;LP16], to better explore data [BCPV+12;Ise16], to better gain knowledge from it [BCPV+12; Ise16;VHE10], and to better communicate insights from data exploration [Ise16;VHE10]. Based on these notions, following definition is provided: Definition 1. ...
... In addition to silhouettes and contours, sparse line illustrations also comprise feature lines-lines that characterize particular features on the surface of the object that are not necessarily characterized by (potential) changes in visibility [LP16]. These feature lines are similarly important to be able to understand the shape of the depicted objects and are typically placed in regions where discontinuities occur. ...
... Due to the challenging character of feature lines, these techniques were not commonly applied to multimodal data visualization so far. Although its potential was shown to illustrate surfaces [LP16] more work needs to be done in this field. ...
This thesis presents selected applications with the aim of visually enhancing
focus structures. It covers four different applications with a
clear problem statement. The solution is anything but simple. Thus, four applications will be presented and analyzed, complemented by their respective solutions. Novel visualization techniques to enhance focus structures will be presented. Furthermore, two overviews of the current state of the art are described, which cover the fields of illustrative
visualization techniques and multimodal data visualization.
... The suggestive contours of De Carlo (DeCarlo, Finkelstein, Rusinkiewicz, & Santella, 2003) were inspiring for us. They are widely used in visualization (Lawonn & Preim, 2016) and relate to the contours artists often draw ( Cole et al., 2009); see also (Judd, Durand, & Adelson, 2007;Sahner, Weber, Prohaska, & Lamecker, 2008). The idea behind suggestive contours extends from the information in occluding contours (J. ...
We exploit a key result from visual psychophysics -- that individuals perceive shape qualitatively -- to develop a geometrical/topological invariant (the Morse-Smale complex) relating image structure with surface structure. Differences across individuals are minimal near certain configurations such as ridges and boundaries, and it is these configurations that are often represented in line drawings. In particular, we introduce a method for inferring qualitative 3D shape from shading patterns that link the shape-from-shading inference with shape-from-contour. For a given shape, certain shading patches become "line drawings" in a well-defined limit. Under this limit, and invariantly, these shading patterns provide a topological description of the surface. We further show that, under this model, the contours partition the surface into meaningful parts using the Morse-Smale complex. Critical contours are the (perceptually) stable parts of this complex and are invariant over a wide class of rendering models. Intuitively, our main result shows that critical contours partition smooth surfaces into bumps and valleys, in effect providing a scaffold on the image from which a full surface can be interpolated.
... This approach was then adapted to the difference-of-Gaussian that was known in imagespace before by Zhang et al. [32] . Feature line techniques can enhance spatial cues on the surface, but they cannot give a spatial impression of the surface [33] . ...
Incorrect spatial interpretation of 3D vascular models is a main perceptional problem in medical visualization. For improved depth perception, we propose supporting anchors between vascular trees and a cylindrical cutaway that serves as an insight for a virtual resection surface or a path for a tumor ablation. The supporting anchors are optimally arranged in a circular manner such that the depth can be perceived without time-consuming interaction. For improved shape perception and distance-encoding, we additionally employ a novel and fast hatching approach that produces results comparable to state-of-the-art techniques. The advantages of our new visualization approach are demonstrated using the example of laparoscopic liver surgery and confirmed in a quantitative user study with 81 participants. The results show that participants were able to assess relative distances more precisely and were most confident using our illustrative visualization approach.
... A technique to illustrate surface features and enhance the spatial impression with lines was presented by Lawonn et al. [21]. For a recent overview on the extraction of feature lines, we refer to [22]. ...
We present novel techniques for visualizing, illustrating, analyzing, and generating carvings in surfaces. In particular, we consider the carvings in the plaster of the cloister of the Magdeburg cathedral, which dates to the 13th century. Due to aging and weathering, the carvings have flattened. Historians and restorers are highly interested in using digitalization techniques to analyze carvings in historic artifacts and monuments and to get impressions and illustrations of their original shape and appearance. Moreover, museums and churches are interested in such illustrations for presenting them to visitors. The techniques that we propose allow for detecting, selecting, and visualizing carving structures. In addition, we introduce an example-based method for generating carvings. The resulting tool, which integrates all techniques, was evaluated by three experienced restorers to assess the usefulness and applicability. Furthermore, we compared our approach with exaggerated shading and other state-of-the-art methods.
... All the presented feature line methods have advantages and disadvantages. An overview of feature line techniques, which summarizes these positive and negative aspects, can be found in the survey by Lawonn and Preim [LP15]. ...
In medical visualization of surface information, problems often arise when visualizing several overlapping structures simultaneously. There is a trade-off between visualizing multiple structures in a detailed way and limiting visual clutter, in order to allow users to focus on the main structures. Illustrative visualization techniques can help alleviate these problems by defining a level of abstraction per structure. However, clinical uptake of these advanced visualization techniques so far has been limited due to the complex parameter settings required. To bring advanced medical visualization closer to clinical application, we propose a novel illustrative technique that offers a seamless transition between various levels of abstraction and detail. Using a single comprehensive parameter, users are able to quickly define a visual representation per structure that fits the visualization requirements for focus and context structures. This technique can be applied to any biomedical context in which multiple surfaces are routinely visualized, such as neurosurgery, radiotherapy planning or drug design. Additionally, we introduce a novel hatching technique, that runs in real-time and does not require texture coordinates. An informal evaluation with experts from different biomedical domains reveals that our technique allows users to design focus-and-context visualizations in a fast and intuitive manner.
... Further subcategories of depth cues are motion-, surface-and illumination-based cues. Common techniques are color scales, glyphs or illustrative line drawings [16,17] . These cues can help to reconstruct the 3D structure of an object perceived by projection onto a 2D image plan. ...
