Multi-projection Display System Based On The Video Capture Card

With rapid development of science and technology and explosion of information, user requirements of display technology are also getting higher and higher especially in such fields as large-scale scientific visualization,computer supported cooperative work,military simulation,engineering design,remote sensing,command,exhibition industry,digital cinema and so on.And main requirements are on high resolution,big display area and deep immersion.Due to the limitation of display size and computing resource,single channel is hard to satisfy the requirements of massive information visualization,so using several projectors to construct multi-channel display applications is becoming much more popular.During constructing multi-projector display,geometry calibration and photometric calibration should be considered.There are already lots of mature methods for geometry calibration,so this paper just focuses on photometric calibration.We focus on using camera to solve photometric problems on chrominance variation and luminance nonuniformity in multi-projector display.A three-phase approach is proposed to construct three models and make transformations among these models.These models are named as single-projector model, normalized-projector model and display-wall model.Single-projector model describes the whole imaging procedure from the projector's input color to its measured tristimulus values in CIEXYZ.Normalized-projector model normalizes each single-projector model,and makes them have the same chrominance and holistie luminance.In display-wall model,the whole display wall will also be regarded as one projector and have the similar photometric model.Through the transformation among these models,photometric problems could be solved.With wide usage of video capture card,using video capture card to capture data as input resource for multi-channel display application will bring speed advantage. The current video capture cards have two kinds of input signal,analog signal and digital signal.The main difference between them is that analog signal will bring some color loss and color shift.So color calibration should be done when using analog video capture card.In this paper,mature delaunay tetrahedralization method is used to calibrate video capture card color.Build lookup table and use high computing ability of GPU in video card to do real time calibration.Base on color calibration,we design on one high-resolution multi-projector display system based on video capture card and PC cluster rendering.This system makes full use of current mainstream hardware(video capture card and GPU on video card),high efficient algorithms are designed to grantee the efficiency of data exchange among each node,and cluster rendering will support more display channels than single rendering server.Experiment results show that the system could run graphics display application efficiently,and provide seamless and uniform display.