Adott nézőpontból helyes tartalom vetítése tetszóleges felületre

Egy ismeretlen, nem egyenletes felületre vetített képi tartalom torzulása jelentősen korlátozza, adott esetben lehetetlenné teszi a színtér használatát vetítési felületként. Ha azonban a torzulás kompenzálható, tetszőleges felület válhat vetíthetővé és lehetővé téve számos alkalmazás megvalósítását (pl.: asztalra vetített billentyűzet, épületre vetített minta, de akár 3D kiterjesztett valóság is megvalósítható). A cikkben megmutatjuk, hogy egy Lambert-féle felület geometriai torzítása kompenzálható aktív fény (azon belül is Gray-kód) alapú fénysugár rekonstrukció használatával, és példákat hozunk az alkalmazásra

A grid-point detection method based on U-net for a structured light system

Accurate detection of the feature points of the projected pattern plays an extremely important role in one-shot 3D reconstruction systems, especially for the ones using a grid pattern. To solve this problem, this paper proposes a grid-point detection method based on U-net. A specific dataset is designed that includes the images captured with the two-shot imaging method and the ones acquired with the one-shot imaging method. Among them, the images in the first group after labeled as the ground truth images and the images captured at the same pose with the one-shot method are cut into small patches with the size of 64x64 pixels then feed to the training set. The remaining of the images in the second group is the test set. The experimental results show that our method can achieve a better detecting performance with higher accuracy in comparison with the previous methods.Comment: http://airccse.org/csit/V10N16.htm

Laboratorij za naprednu 3D rekonstrukciju i registraciju površina

Laboratorij za naprednu 3D rekonstrukciju i registraciju površina (engl. Advanced Shape Reconstruction and Registration Laboratory - SHARK Lab) osnovan je 2016. godine kao istraživački laboratorij na Sveučilištu u Zagrebu, Fakultetu elektrotehnike i računarstva (FER). SHARK Lab okuplja istraživače sa Zavoda za elektroničke sustave i obradbu informacija i sa Zavoda za elektroniku, mikroelektroniku, računalne i inteligentne sustave. Istraživačka djelatnost usmjerena je poglavito na metode i algoritme računalnog vida, i to za područja: 3D oslikavanje i 3D rekonstrukciju korištenjem profilometrije strukturiranim svjetlom te stereo vidom; 3D registracija oblaka točaka s naglaskom na uporabu senzora mobilnih platformi poput pametnih telefona i tableta; i postupci za kalibraciju sustava 3D oslikavanja koji koriste više kamera i više projektora, posebice sustava namijenjenih za korištenje u biomedicini te sustava oslikavanja za 3D printanje. SHARK Lab je član Centra izvrsnosti za računalni vid i Centra za umjetnu inteligenciju na Fakultetu elektrotehnike i računarstva Sveučilišta u Zagrebu

Laboratorij za naprednu 3D rekonstrukciju i registraciju površina

Laboratorij za naprednu 3D rekonstrukciju i registraciju površina (engl. Advanced Shape Reconstruction and Registration Laboratory - SHARK Lab) osnovan je 2016. godine kao istraživački laboratorij na Sveučilištu u Zagrebu, Fakultetu elektrotehnike i računarstva (FER). SHARK Lab okuplja istraživače sa Zavoda za elektroničke sustave i obradbu informacija i sa Zavoda za elektroniku, mikroelektroniku, računalne i inteligentne sustave. Istraživačka djelatnost usmjerena je poglavito na metode i algoritme računalnog vida, i to za područja: 3D oslikavanje i 3D rekonstrukciju korištenjem profilometrije strukturiranim svjetlom te stereo vidom; 3D registracija oblaka točaka s naglaskom na uporabu senzora mobilnih platformi poput pametnih telefona i tableta; i postupci za kalibraciju sustava 3D oslikavanja koji koriste više kamera i više projektora, posebice sustava namijenjenih za korištenje u biomedicini te sustava oslikavanja za 3D printanje. SHARK Lab je član Centra izvrsnosti za računalni vid i Centra za umjetnu inteligenciju na Fakultetu elektrotehnike i računarstva Sveučilišta u Zagrebu

IN- SITU STRUCTURED LIGHT TECHNIQUES STUDY TO INSPECT SURFACES DURING ADDITIVE MANUFACTURE

Three-dimensional (3D) shape measurement techniques play an increasingly important role in the quality control proceedures of industry, such as aerospace, bioengineering, information security, automobile, integrated circuits and so on. Additive manufacturing (AM) provide significant advantages over conventional subtractive manufacturing techniques in terms of the wide range of part geometry that can be obtained. The key metal AM technology is powder bed processing. During the AM process, powder delivery occurs thousands of times. Therefore, the assessment of delivery quality would be advantageous for the process to provide feedback for process control. After the energy source melts the powder bed, the detection of the machined surface is also a critically important criterion for the evaluation of the manufacturing quality. This thesis presents an in-situ quantitative inspection technique for the powder bed post raking and printed surface after melting, the technique uses fringe projection profilometry. In this thesis, system calibration methods, phase analysis algorithms, and error correction methods are investigated. A novel surface fitting algorithm is employed to reduce the influence of phase error and random noise during system calibration. A novel intelligent fringe projection technique using a support-vector-machine (SVM) algorithm is proposed to measure the 3D topography of high dynamic range surfaces on a layer by layer basis within the EBAM machine. A simple calibration method is used to eliminate phase errors during system calibration. The proposed in-situ inspection technique has been installed on a commercial electron beam melting (EBM) AM machine. Exemplar powder beds with defects and printed surfaces, are measured with the proposed technique. The whole inspection process lasts less than 5 seconds. Experimental results showed that the powder and the melting surface defects could be efficiently inspected using the proposed system and the measurement result could be fed back to the build process to improve the processing quality. For the inspection of highly reflective surface geometries that have been further machined post AM, phase measuring deflectometry (PMD) has been widely studied for the 3D form measurement. This thesis presents a new direct PMD (DPMD) method that measures the full-field 3D shape of complicated specular objects. A mathematical model is derived to directly relate an absolute phase map to depth data, instead of the gradient. The 3D shape of a monolithic multi-mirror array having multiple specular surfaces was measured. Experimental results show that the proposed DPMD method can obtain the full-field 3D shape of specular objects having isolated and/or discontinuous surfaces accurately and effectively. In this thesis, the fringe projection and the deflectometry techniques are studied. Two different measurement systems were used to measure different roughness surfaces. The experimental results shows the rough surfaces, reflective surfaces, and the highly reflective specular surfaces can be measured and reconstructed by the proposed methods