Leandro Cruz

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Leandro received his licentiate degree in Math from Universidade Estadual do Norte Fluminense Darcy Ribeiro (2006), and BSc from Universidade Cândido Mendes (2009). In 2011, he received the master degree, in Math - option computer graphics, and in 2015 the PhD degree in Math, both from Instituto Nacional de Matemática Pura e Aplicada (IMPA). During his PhD, he also visited for one year the LIRIS (Laboratoire d'InfoRmatique en Image et Systèmes d'information, em Lyon, França).
During 2015 and 2016, he was a postdoc at IMPA, developing research about creating a visual representation for textures and pieces of music. Since February 2017, he joined to VIS Team, at University of Coimbra. First, he worked at TrustStamp project, participating in the development of UniQode. Currently, he is the manager of VIS Team, collaborating on three current projects: TrustStamp/TrustFaces, UniqueMark, and Card3dFaces.

Projects

Card3DFace

This project intends to create a 3D face printing system on cards. As for printing on polymer cards,...

TrustStamp

This project intends to develop verification tools to be applied on INCM trust stamps, to confirm au...

UniqueMark

This project aims to improve the safety of INCM's contrasting marks in precious metal artefacts (the...

TrustFaces

This project will start soon.

Publications

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.

  • Date: 30/11/2017
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  • Featured In: SIGGRAPH Asia 2017
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  • Publication Type: Conference Papers
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  • Author(s): Bruno Patrão, Leandro Cruz, Nuno Gonçalves
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  • DOI: 10.1145/3145690.3145705
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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.

  • Date: 03/07/2018
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  • Featured In: Eurographics 2018
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  • Publication Type: Conference Papers
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  • Author(s): Bruno Patrão, Leandro Cruz, Nuno Gonçalves
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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.

  • Date: 25/03/2018
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  • Featured In: Eurographics 2018 Posters
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  • Publication Type: Poster
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  • Author(s): Leandro Dihl, Leandro Cruz, Nuno Gonçalves
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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.

  • Date: 26/10/2018
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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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  • Author(s): Dirce Celorico, Leandro Cruz, Leandro Dihl, Nuno Gonçalves
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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.

  • Date: 25/02/2019
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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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  • Author(s): Leandro Dihl, Leandro Cruz, Nuno Monteiro, Nuno Gonçalves
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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.

  • Date: 26/10/2018
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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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  • Author(s): Leandro Cruz, Bruno Patrão, Nuno Gonçalves
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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.

  • Date: 10/12/2018
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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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  • Author(s): Leandro Cruz, Bruno Patrão, Nuno Gonçalves
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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.

  • Date: 10/12/2018
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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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  • Author(s): Leandro Cruz, Bruno Patrão, Nuno Gonçalves
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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.

  • Date: 26/10/2018
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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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  • Author(s): Ricardo Barata, Leandro Cruz, Bruno Patrão, Nuno Gonçalves
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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.

  • Date: 26/10/2018
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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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  • Author(s): Leandro Dihl, Leandro Cruz, Nuno Gonçalves
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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).

  • Date: 10/12/2018
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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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  • Author(s): Leandro Cruz, Bruno Patrão, Nuno Gonçalves
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  • DOI: DOI: 10.1109/AIVR.2018.00036
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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.

  • Date: 24/07/2019
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  • Featured In: Jewellery Materials Congress 2019
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  • Publication Type: Conference Papers
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  • Author(s): Nuno Gonçalves, Leandro Cruz
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