Practical Non-linear Photometric Projector Compensation

Abstract

We propose a novel approach to generate a high quality photometric compensated projection which, to our knowledge, is the first one, which does not require a radiometrical pre-calibration of cameras or projectors. This improves the compensation quality using devices which cannot be easily linearized, such as single chip DLP projectors with complex color processing. In addition, the simple workflow significantly simplifies the compensation image generation. Our approach consists of a sparse sampling of the projector's color gamut and a scattered data interpolation to generate the per-pixel mapping from projector to camera colors in real-time. To avoid out-of-gamut artifacts, the input image is automatically scaled locally in an optional off-line optimization step maximizing the achievable luminance and contrast while still preserving smooth input gradients without significant clipping errors.

Augmenting physical avatars using projector-based illumination

“…We used a modified version of SSIM to compare the projection results of uncompensated and compensated shadings to a ground truth image. This was generated by rendering the input image from a calibrated camera and using the color mapping technique described in [Grundhöfer 2013] in an inverse manner to simulate the per-pixel surface color modulations. It has been modified in that it does not take the absolute pixel values into account, but only compares contrast and structure.…”

Recent Advances in Projection Mapping Algorithms, Hardware and Applications

“…A more accurate color reproduction, especially when applied to single-chip DMD-based projectors using multi-primary color † Please refer to a state-of-the-art report [BIWG08] for details wheels and an internal non-linear color processing is achieved using a non-linear thin-plate-spline interpolation [Gru13]. While this requires a significantly more complex interpolation model based on radial basis functions (RBF) to be calculated and solved, it could be shown that the resulting improvement in compensation quality is applicable for real-time processing when implemented on the GPU.…”

Adaptive stray-light compensation in dynamic multi-projection mapping

“…Obviously, this is impossible. Solving a global non-linear optimization problem as discussed in Grundhöfer [10] is a solution to this problem. However, for our real-time system the performance of this approach is prohibitive.…”