Shape from shading with specular highlights: Analysis of the Phong model

Breuβ, Michael; Ju, Yong Chul

doi:10.1109/icip.2011.6116732

Cited by 3 publications

(2 citation statements)

References 13 publications

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“…Oren and Nayar proposed a more accurate Oren–Nayar reflection model based on the Lambertian reflection model, which is closer to the actual reflection characteristics [ 16 ]. Based on the Phong model, Breuß proposed the perspective Phong-based SFS (P2SFS) model, which is more in line with the camera's perspective imaging characteristics [ 17 ]. Yang replaced the ideal Lambertian model with a radial basis function (RBF) reflection model and used neural networks to solve the problem of nonlinear equations [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

A Novel Approach to Droplet’s 3D Shape Recovery Based on Mask R-CNN and Improved Lambert–Phong Model

Ren

Zhang

et al. 2018

Micromachines

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Aiming at the demand for extracting the three-dimensional shapes of droplets in microelectronic packaging, life science, and some related fields, as well as the problems of complex calculation and slow running speed of conventional shape from shading (SFS) illumination reflection models, this paper proposes a Lambert–Phong hybrid model algorithm to recover the 3D shapes of micro-droplets based on the mask regions with convolutional neural network features (R-CNN) method to extract the highlight region of the droplet surface. This method fully integrates the advantages of the Lambertian model’s fast running speed and the Phong model’s high accuracy for reconstruction of the highlight region. First, the Mask R-CNN network is used to realize the segmentation of the highlight region of the droplet and obtain its coordinate information. Then, different reflection models are constructed for the different reflection regions of the droplet, and the Taylor expansion and Newton iteration method are used for the reflection model to get the final height of all positions. Finally, a three-dimensional reconstruction experimental platform is built to analyze the accuracy and speed of the algorithm on the synthesized hemisphere image and the actual droplet image. The experimental results show that the proposed algorithm based on mask R-CNN had better precision and shorter running time. Hence, this paper provides a new approach for real-time measurement of 3D droplet shape in the dispensing state.

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Section: Introductionmentioning

confidence: 99%

A Novel Approach to Droplet’s 3D Shape Recovery Based on Mask R-CNN and Improved Lambert–Phong Model

Ren

Zhang

et al. 2018

Micromachines

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“…[6]), no such thorough analysis has been performed for the advanced Oren-Nayar model so far. Moreover, to the best of our knowledge, there is only one work in the entire literature that presents such an in-depth study for a modern non-Lambertian SfS model: In [5], Breuß and Ju investigate important issues such as critical points and convexity in the context of SfS with the Phong model [25].…”

Section: Introductionmentioning

confidence: 99%

Shape from Shading for Rough Surfaces: Analysis of the Oren-Nayar Model

Breuß

Bruhn

et al. 2012

Procedings of the British Machine Vision Conference 2012

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Due to their improved capability to handle realistic illumination scenarios, nonLambertian reflectance models are becoming increasingly more popular in the Shape from Shading (SfS) community. One of these advanced models is the Oren-Nayar model which is particularly suited to handle rough surfaces. However, not only the proper selection of the model is important, also the validation of stable and efficient algorithms plays a fundamental role when it comes to the practical applicability. While there are many works dealing with such algorithms in the case of Lambertian SfS, no such analysis has been performed so far for the Oren-Nayar model. In our paper we address this problem and present an in-depth study for such an advanced SfS model. To this end, we investigate under which conditions, i.e. model parameters, the Fast Marching (FM) method can be applied -a method that is known to be one of the most efficient algorithms for solving the underlying partial differential equations of Hamilton-Jacobi type. In this context, we do not only perform a general investigation of the model using Osher's criterion for verifying the suitability of the FM method. We also conduct a parameter dependent analysis that shows, that FM can safely be used for the model for a wide range of settings relevant for practical applications. Thus, for the first time, it becomes possible to theoretically justify the use of the FM method as solver for the Oren-Nayar model which has been applied so far on a purely empirical basis only. Numerical experiments demonstrate the validity of our theoretical analysis. They show a stable behaviour of the FM method for the predicted range of model parameters.

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The Highlight Ovals

Bartoli

2019

J Math Imaging Vis

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Shape from shading with specular highlights: Analysis of the Phong model

Cited by 3 publications

References 13 publications

A Novel Approach to Droplet’s 3D Shape Recovery Based on Mask R-CNN and Improved Lambert–Phong Model

A Novel Approach to Droplet’s 3D Shape Recovery Based on Mask R-CNN and Improved Lambert–Phong Model

Shape from Shading for Rough Surfaces: Analysis of the Oren-Nayar Model

The Highlight Ovals

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