671 research outputs found
Colour-based image retrieval algorithms based on compact colour descriptors and dominant colour-based indexing methods
Content based image retrieval (CBIR) is reported as one of the most active research
areas in the last two decades, but it is still young. Three CBIR’s performance problem in this study is inaccuracy of image retrieval, high complexity of feature extraction, and degradation of image retrieval after database indexing. This situation led to discrepancies to be applied on limited-resources devices (such as mobile devices). Therefore, the main objective of this thesis is to improve performance of CBIR. Images’ Dominant Colours (DCs) is selected as the key contributor for this purpose due to its compact property and its compatibility with the human visual system. Semantic image retrieval is proposed to solve retrieval inaccuracy problem by concentrating on the images’ objects. The effect of image background is reduced to provide more focus on the object by setting weights to the object and the background DCs. The accuracy improvement ratio is raised up to 50% over the compared methods. Weighting DCs framework is proposed to generalize this technique where it is demonstrated by applying it on many colour descriptors. For reducing high complexity of colour Correlogram in terms of computations and
memory space, compact representation of Correlogram is proposed. Additionally, similarity measure of an existing DC-based Correlogram is adapted to improve its accuracy. Both methods are incorporated to produce promising colour descriptor in terms of time and memory space complexity. As a result, the accuracy is increased up to 30% over the existing methods and the memory space is decreased to less than 10% of its original space. Converting the abundance of colours into a few DCs framework is proposed to generalize DCs concept. In addition, two DC-based
indexing techniques are proposed to overcome time problem, by using RGB and perceptual LUV colour spaces. Both methods reduce the search space to less than 25% of the database size with preserving the same accuracy
VToonify: Controllable High-Resolution Portrait Video Style Transfer
Generating high-quality artistic portrait videos is an important and
desirable task in computer graphics and vision. Although a series of successful
portrait image toonification models built upon the powerful StyleGAN have been
proposed, these image-oriented methods have obvious limitations when applied to
videos, such as the fixed frame size, the requirement of face alignment,
missing non-facial details and temporal inconsistency. In this work, we
investigate the challenging controllable high-resolution portrait video style
transfer by introducing a novel VToonify framework. Specifically, VToonify
leverages the mid- and high-resolution layers of StyleGAN to render
high-quality artistic portraits based on the multi-scale content features
extracted by an encoder to better preserve the frame details. The resulting
fully convolutional architecture accepts non-aligned faces in videos of
variable size as input, contributing to complete face regions with natural
motions in the output. Our framework is compatible with existing StyleGAN-based
image toonification models to extend them to video toonification, and inherits
appealing features of these models for flexible style control on color and
intensity. This work presents two instantiations of VToonify built upon Toonify
and DualStyleGAN for collection-based and exemplar-based portrait video style
transfer, respectively. Extensive experimental results demonstrate the
effectiveness of our proposed VToonify framework over existing methods in
generating high-quality and temporally-coherent artistic portrait videos with
flexible style controls.Comment: ACM Transactions on Graphics (SIGGRAPH Asia 2022). Code:
https://github.com/williamyang1991/VToonify Project page:
https://www.mmlab-ntu.com/project/vtoonify
Motion enriching using humanoide captured motions
Animated humanoid characters are a delight to watch. Nowadays they are extensively
used in simulators. In military applications animated characters are used for training
soldiers, in medical they are used for studying to detect the problems in the joints of a
patient, moreover they can be used for instructing people for an event(such as weather
forecasts or giving a lecture in virtual environment). In addition to these environments
computer games and 3D animation movies are taking the benefit of animated characters
to be more realistic. For all of these mediums motion capture data has a great impact
because of its speed and robustness and the ability to capture various motions.
Motion capture method can be reused to blend various motion styles. Furthermore we
can generate more motions from a single motion data by processing each joint data
individually if a motion is cyclic. If the motion is cyclic it is highly probable that each
joint is defined by combinations of different signals. On the other hand, irrespective of
method selected, creating animation by hand is a time consuming and costly process for
people who are working in the art side. For these reasons we can use the databases
which are open to everyone such as Computer Graphics Laboratory of Carnegie Mellon
University.Creating a new motion from scratch by hand by using some spatial tools (such as 3DS
Max, Maya, Natural Motion Endorphin or Blender) or by reusing motion captured data
has some difficulties. Irrespective of the motion type selected to be animated
(cartoonish, caricaturist or very realistic) human beings are natural experts on any kind
of motion. Since we are experienced with other peoples’ motions, and comparing each
motion to the others, we can easily judge one individual’s mood from his/her body
language. As being a natural master of human motions it is very difficult to convince
people by a humanoid character’s animation since the recreated motions can include
some unnatural artifacts (such as foot-skating, flickering of a joint)
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