Optimizing Multiple Camera Positions for the Deflectometric Measurement of Multiple Varying Targets

We present a device for detection of hail dents in passenger cars. For this purpose we have constructed a new multi-camera deflectometric setup for large specular objects. Deflectometric measurements have strict constraints how cameras can be placed – for instance: angular restrictions and distance limitations. An important trait of our system is the static setup – we use a single setup for camera configuration for all objects to be scanned. We render the camera images and analyze them for the deflectometric needs to optimize the camera placement w.r. t. multiple parameters. Important ones are the positions of the cameras – reflections of the patterns should be clearly visible. Camera parameters are computed using a global optimization procedure for which we efficiently generate a good starting configuration. We introduce an empiric quality measure of a particular camera configuration and present both visual and quantitative results for the generated camera placement. This configuration was then used to build the actual device.