Publications de Marjan Shahpaski

Precise and accurate image-based measurements of optical material properties

The appearance of objects is governed by how they reflect, transmit and absorb the light they receive. That, in turn, depends on the material's internal structure, surface structure, and viewing and illumination directions. Changes in those characteristics ...

EPFL2020

Solving the Depth Ambiguity in Single-Perspective Images

Sabine Süsstrunk, Marjan Shahpaski, Majed El Helou

Scene depth estimation is gaining in importance as more and more AR/VR and robot vision applications are developed. Conventional depth-from-defocus techniques can passively provide depth maps from a single image. This is especially advantageous for moving ...

2019

Magic Prints: Image-Changing Prints Observed under Visible and 365 nm UV Light

Petar Pjanic, Marjan Shahpaski

In this paper we propose a novel layered-printing method consisting of superposed visible cmy and invisible fluorescent ultraviolet (UV) rgb inks. Our approach can be used to generate a variety of visual color-alteration effects such as revealing two compl ...

I S & T-SOC IMAGING SCIENCE TECHNOLOGY2019

Closed-Form Solution to Disambiguate Defocus Blur in Single-Perspective Images

Sabine Süsstrunk, Marjan Shahpaski, Majed El Helou

Depth-from-defocus techniques suffer an ambiguity problem where depth planes on opposite sides of the focal plane have identical defocus. We solve the ambiguity by relying on the wavelength-dependent relationship between defocus and depth. We conduct a rob ...

2019

Comparative analysis of transmittance measurement geometries and apparatus

Sabine Süsstrunk, Marjan Shahpaski

The accurate measurement of reflectance and transmittance properties of materials is essential in the printing and display industries in order to ensure precise color reproduction. In comparison with reflectance measurement, where the impact of different g ...

2019

NTIRE 2018 Challenge on Spectral Reconstruction from RGB Images

Radu Timofte, Marjan Shahpaski, Ruofan Zhou, Fayez Lahoud, Majed El Helou, Dong Liu, Lei Zhang, Soumik Sarkar, Himanshu Sharma, Bing Zhang, Chang Chen

This paper reviews the first challenge on spectral image reconstruction from RGB images, i.e., the recovery of whole-scene hyperspectral (HS) information from a 3- channel RGB image. The challenge was divided into 2 tracks: the “Clean” track sought HS reco ...

2018

Simultaneous Geometric and Radiometric Calibration of a Projector-Camera Pair

Sabine Süsstrunk, Marjan Shahpaski

We present a novel method that allows for simultaneous geometric and radiometric calibration of a projector-camera pair. It is simple and does not require specialized hardware. We prewarp and align a specially designed projection pattern onto a printed pat ...

IEEE2017