Publications

Publications related to the VIS Team

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  • Publication Type: Thesis
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  • Year: 2020

UniqueMark - A method to create and authenticate a unique mark in precious metal artefacts

The project UniqueMark aims at creating a system to provide a precious metal artefact with a unique, unclonable and irreproducible mark, and at building a system for the validation of authenticity of it. This system verifies the mark authenticity using a microscope, or a smartphone camera with attached macro lens.

  • Author(s): Nuno Gonçalves, Leandro Cruz
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  • Featured In: Jewellery Materials Congress 2019
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  • Publication Type: Conference Papers
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  • Year: 2019
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A Content-aware Filtering for RGBD Faces

A content-aware filtering for 2.5D meshes of faces that preserves their intrinsic features. We take advantage of prior knowledge of the models (faces) to improve the comparison. The model is invariant to depth translation and scale. The proposed method is evaluated on a public 3D face dataset with different levels of noise. The results show that the method is able to remove noise without smoothing the sharp features of the face.

  • Author(s): Leandro Dihl, Leandro Cruz, Nuno Monteiro, Nuno Gonçalves
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  • Featured In: GRAPP 2019 - International Conference on Computer Graphics Theory and Applications
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  • Publication Type: Conference Papers
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  • Year: 2019
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Large Scale Information Marker Coding for Augmented Reality Using Graphic Code

The main advantage of using this approach as an Augmented Reality marker is the possibility of creating generic applications that can read and decode these Graphic Code markers, which might contain 3D models and complex scenes encoded in it. Additionally, the resulting marker has strong aesthetic characteristics associated to it once it is generated from any chosen base image.

  • Author(s): Leandro Cruz, Bruno Patrão, Nuno Gonçalves
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  • Featured In: IEEE International Conference on Artificial Intelligence and Virtual Reality (AIVR)
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  • Publication Type: Conference Papers
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  • Year: 2018
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An Augmented Reality Application Using Graphic Code Markers

Presenting applications of the Graphic Code, exploiting its large-scale information coding capabilities applied to Augmented Reality.

  • Author(s): Leandro Cruz, Bruno Patrão, Nuno Gonçalves
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  • Featured In: IEEE International Conference on Artificial Intelligence and Virtual Reality (AIVR)
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  • Publication Type: Other
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  • Year: 2018
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Graphic Code: a New Machine Readable Approach

Graphic Code has two major advantages over classical MRCs: aesthetics and larger coding capacity. It opens new possibilities for several purposes such as identification, tracking (using a specific border), and transferring of content to the application. This paper focuses on presenting how graphic code can be used for industry applications, emphasizing its uses on Augmented Reality (AR).

  • Author(s): Leandro Cruz, Bruno Patrão, Nuno Gonçalves
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  • Featured In: IEEE International Conference on Artificial Intelligence and Virtual Reality (AIVR)
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  • Publication Type: Conference Papers
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  • DOI: DOI: 10.1109/AIVR.2018.00036
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  • Year: 2018
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Use of Epipolar Images Towards Outliers Extraction in Depth Images

Method for filtering the depth model, reconstructed from light field cameras, based on the removal of low confidence reconstructed values and using an inpainting method to replace them. This approach has shown good results for outliers removal.

  • Author(s): Dirce Celorico, Leandro Cruz, Leandro Dihl, Nuno Gonçalves
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  • Featured In: Recpad 2018-24th Portuguese Conference on Pattern Recognition
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  • Publication Type: Poster
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  • Year: 2018
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Graphic Code: Creation, Detection and Recognition

Graphic Code is a new Machine Readable Coding (MRC) method. It creates coded images by organizing available primitive graphic units arranged according to some predefined patterns. Some of these patterns are previously associated with symbols used to compose the messages and to define a dictionary.

  • Author(s): Leandro Cruz, Bruno Patrão, Nuno Gonçalves
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  • Featured In: Recpad 2018-24th Portuguese Conference on Pattern Recognition
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  • Publication Type: Poster
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  • Year: 2018
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Uniquemark: A computer vision system for hallmarks authentication

Uniquemark is a vision system for authentication based on random marks, particularly hallmarks. Hallmarks are worldwide used to authenticate and attest the legal fineness of precious metal artefacts. Our authentication method is based on a multiclass classifier model that uses mark descriptor composed by several geometric features of the particles.

  • Author(s): Ricardo Barata, Leandro Cruz, Bruno Patrão, Nuno Gonçalves
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  • Featured In: Recpad 2018-24th Portuguese Conference on Pattern Recognition
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  • Publication Type: Thesis
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  • Year: 2018
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Improving Facial Depth Data by Exemplar-based Comparisons

Presented a filtering method for meshes of faces preserving their intrinsic features. It is based in an exemplar-based neighborhood matching where all models are in a frontal position avoiding rotation and perspective drawbacks. Moreover, the model is invariant to depth translation and scale.

  • Author(s): Leandro Dihl, Leandro Cruz, Nuno Gonçalves
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  • Featured In: Recpad 2018-24th Portuguese Conference on Pattern Recognition
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  • Publication Type: Poster
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  • Year: 2018
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Halftone Pattern: A New Steganographic Approach

Presentation of a steganographic technique to hide a textual information into an image. It is inspired by the use of dithering to create halftone images. It begins from a base image and creates the coded image by associating each base image pixel to a set of two-colors pixels (halftone) forming an appropriate pattern. The coded image is a machine readable information, with good aesthetic, secure and containing data redundancy and compression.

  • Author(s): Bruno Patrão, Leandro Cruz, Nuno Gonçalves
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  • Featured In: Eurographics 2018
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  • Publication Type: Conference Papers
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  • Year: 2018
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Exemplar Based Filtering of 2.5D Meshes of Faces

Presentation of a content-aware filtering for 2.5D meshes of faces. An exemplar-based filter that corrects each point of a given mesh through local model-exemplar neighborhood comparison taking advantage of prior knowledge of the models (faces) to improve the comparison.

  • Author(s): Leandro Dihl, Leandro Cruz, Nuno Gonçalves
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  • Featured In: Eurographics 2018 Posters
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  • Publication Type: Poster
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  • Year: 2018
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An Application of a Halftone Pattern Coding in Augmented Reality

Presentation of a coding system using a halftone pattern (with black and white pixels) capable to be integrated into markers that encode information that can be retrieved a posteriori and used in the creation of augmented reality applications. These markers can be easily detected in a photo and the encoded information is the basis for parameterizing various types of augmented reality applications.

  • Author(s): Bruno Patrão, Leandro Cruz, Nuno Gonçalves
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  • Featured In: SIGGRAPH Asia 2017
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  • Publication Type: Conference Papers
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  • DOI: 10.1145/3145690.3145705
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  • Year: 2017
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  • Publication Type: Thesis
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  • Year: 2017