Image Render-Capture Applications

Опубликовано 17 августа 2016, 21:20

Two very different applications that use a render-capture paradigm will be presented; the first is a projector-camera system and the second uses a print-scan process. In anticipation of the proliferation of micro-projectors on handheld imaging devices, we designed and tested a projector-camera system that allows a distant user to point into a remote 3D environment with a projector. The solution involves a means for locating a projected dot, and for adjusting its location to correspond to a position indicted by a remote user viewing the scene through a camera. While many projector-camera systems require a calibration phase, our solution allows calibration-free operation. The tracking algorithm is implemented with a modified 2D gradient decent method that performs even in the presence of spatial discontinuities. Our prototype performs real-time and accurate tracking across irregularly shaped and colored surfaces. Tests with Inter-continental separations of client and server suffered no loss of responsiveness. An alternative to unsightly barcodes is a new method for embedding data into an image halftone. The process takes as input any image and a payload of data to be encoded and produces a bitonal clustered-dot halftone of that image with selected halftone clusters shifted to carry varying number of bits from the payload. The resulting data-bearing steganographic halftone is referred to as a ΓÇ£StegatoneΓÇ¥. Because of the small size and large number of clustered-dot cells in printed halftones the bit density is quite high. Scans of printed Stegatones from a number of printers support the robustness of the method with high data recovery rates.