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Lighting-up geometry: accurate 3D modelling with a torch and a camera. George Vogiatzis, Carlos Hern á ndez, Roberto Cipolla University of Cambridge, Toshiba Research. Our technique. Aquire high-res mesh from images taken under changing camera position and illumination
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Lighting-up geometry: accurate 3D modelling with a torch and a camera George Vogiatzis, Carlos Hernández, Roberto Cipolla University of Cambridge, Toshiba Research
Our technique • Aquire high-res mesh from images taken under changing camera position and illumination • Changing illumination uncovers fine geometric detail • Assumptions: • Lambertian surface, isolated highlights • Single, distant light-source • Silhouettes of object can be extracted
In a nutshell: • Estimate light direction in each image • With known light directionscan estimate surface normals n from pixel intensities i • Integrate normals to get geometry n l i
Light estimation • Calibration object • Fully known geometry • Light can be estimated from intensity of all points
Light estimation • Visual hull
Light estimation • Virtual calibration object • Partially known geometry • Light can be estimated from intensity of correct points
Surface Evolution: Deformable 3D Mesh Evolve mesh until it is predicted appearance under recovered illumination matches images
Advantages • Fully uncalibrated. Camera position and illumination are recovered from images alone • Low cost, practical and efficient alternative to laser range scanning • First image based method to obtain full 3D geometry of untextured objects