2,942 research outputs found
A Rectangular Area Filling Display System Architecture
A display system architecture which has rectangular area filling as its primitive operation is presented. It is shown that lines can be drawn significantly faster while rendition of filled boxes shows an O(n^2) speed improvement. Furthermore filled polygons can be rendered with an O(n) speed improvement.
Implementation of this rectangular area filling architecture is discussed and refined. A custom
VLSI integrated circuit is currently being designed to implement this rectangular area filling architecture
and at the same time reduce the display memory system video refresh bandwidth requirements
Automatic Structural Scene Digitalization
In this paper, we present an automatic system for the analysis and labeling
of structural scenes, floor plan drawings in Computer-aided Design (CAD)
format. The proposed system applies a fusion strategy to detect and recognize
various components of CAD floor plans, such as walls, doors, windows and other
ambiguous assets. Technically, a general rule-based filter parsing method is
fist adopted to extract effective information from the original floor plan.
Then, an image-processing based recovery method is employed to correct
information extracted in the first step. Our proposed method is fully automatic
and real-time. Such analysis system provides high accuracy and is also
evaluated on a public website that, on average, archives more than ten
thousands effective uses per day and reaches a relatively high satisfaction
rate.Comment: paper submitted to PloS On
From 3D Models to 3D Prints: an Overview of the Processing Pipeline
Due to the wide diffusion of 3D printing technologies, geometric algorithms
for Additive Manufacturing are being invented at an impressive speed. Each
single step, in particular along the Process Planning pipeline, can now count
on dozens of methods that prepare the 3D model for fabrication, while analysing
and optimizing geometry and machine instructions for various objectives. This
report provides a classification of this huge state of the art, and elicits the
relation between each single algorithm and a list of desirable objectives
during Process Planning. The objectives themselves are listed and discussed,
along with possible needs for tradeoffs. Additive Manufacturing technologies
are broadly categorized to explicitly relate classes of devices and supported
features. Finally, this report offers an analysis of the state of the art while
discussing open and challenging problems from both an academic and an
industrial perspective.Comment: European Union (EU); Horizon 2020; H2020-FoF-2015; RIA - Research and
Innovation action; Grant agreement N. 68044
Reconstructing vectorised photographic images
We address the problem of representing captured images in the continuous mathematical space more usually associated with certain forms of drawn ('vector') images. Such an image is resolution-independent so can be used as a master for varying resolution-specific formats. We briefly describe the main features of a vectorising codec for photographic images, whose significance is that drawing programs can access images and image components as first-class vector objects. This paper focuses on the problem of rendering from the isochromic contour form of a vectorised image and demonstrates a new fill algorithm which could also be used in drawing generally. The fill method is described in terms of level set diffusion equations for clarity. Finally we show that image warping is both simplified and enhanced in this form and that we can demonstrate real histogram equalisation with genuinely rectangular histograms
Scanning and Sequential Decision Making for Multi-Dimensional Data - Part I: the Noiseless Case
We investigate the problem of scanning and prediction ("scandiction", for
short) of multidimensional data arrays. This problem arises in several aspects
of image and video processing, such as predictive coding, for example, where an
image is compressed by coding the error sequence resulting from scandicting it.
Thus, it is natural to ask what is the optimal method to scan and predict a
given image, what is the resulting minimum prediction loss, and whether there
exist specific scandiction schemes which are universal in some sense.
Specifically, we investigate the following problems: First, modeling the data
array as a random field, we wish to examine whether there exists a scandiction
scheme which is independent of the field's distribution, yet asymptotically
achieves the same performance as if this distribution was known. This question
is answered in the affirmative for the set of all spatially stationary random
fields and under mild conditions on the loss function. We then discuss the
scenario where a non-optimal scanning order is used, yet accompanied by an
optimal predictor, and derive bounds on the excess loss compared to optimal
scanning and prediction.
This paper is the first part of a two-part paper on sequential decision
making for multi-dimensional data. It deals with clean, noiseless data arrays.
The second part deals with noisy data arrays, namely, with the case where the
decision maker observes only a noisy version of the data, yet it is judged with
respect to the original, clean data.Comment: 46 pages, 2 figures. Revised version: title changed, section 1
revised, section 3.1 added, a few minor/technical corrections mad
Low-level processing for real-time image analysis
A system that detects object outlines in television images in real time is described. A high-speed pipeline processor transforms the raw image into an edge map and a microprocessor, which is integrated into the system, clusters the edges, and represents them as chain codes. Image statistics, useful for higher level tasks such as pattern recognition, are computed by the microprocessor. Peak intensity and peak gradient values are extracted within a programmable window and are used for iris and focus control. The algorithms implemented in hardware and the pipeline processor architecture are described. The strategy for partitioning functions in the pipeline was chosen to make the implementation modular. The microprocessor interface allows flexible and adaptive control of the feature extraction process. The software algorithms for clustering edge segments, creating chain codes, and computing image statistics are also discussed. A strategy for real time image analysis that uses this system is given
Artistic vision: painterly rendering using computer vision techniques
Journal ArticleWe present a method that takes a raster image as input and produces a painting-like image composed of strokes rather than pixels. Unlike previous automatic painting methods, we attempt to keep the number of brush-stroke small. This is accomplished by first segmenting the image into features, finding the medial axes points of these features, converting the medial axes points into ordered lists of image tokens, and finally rendering these lists as brush strokes. Our process creates images reminiscent of modern realist painters who often want an abstract or sketchy quality in their work
Topographic map visualization from adaptively compressed textures
Raster-based topographic maps are commonly used in geoinformation systems to overlay geographic entities on top of digital terrain models. Using compressed texture formats for encoding topographic maps allows reducing latency times while visualizing large geographic datasets. Topographic maps encompass high-frequency content with large uniform regions, making current compressed texture formats inappropriate for encoding them. In this paper we present a method for locally-adaptive compression of topographic maps. Key elements include a Hilbert scan to maximize spatial coherence, efficient encoding of homogeneous image regions through arbitrarily-sized texel runs, a cumulative run-length encoding supporting fast random-access, and a compression algorithm supporting lossless and lossy compression. Our scheme can be easily implemented on current programmable graphics
hardware allowing real-time GPU decompression and rendering of bilinear-filtered topographic maps.Postprint (published version
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