Abstract:
An image having m light sources, with m preferably equaling 2 or 3, is segmented into different regions, each of which is lit by only one of the m light sources, by obtaining paired imaged with different filtering, for example a filtered and an unfiltered image, applying to the image pairs sets of m pre-computed mappings at the pixel or region level, and selecting the most appropriate. The rendering of the information in the image maybe adjusted accordingly.
Abstract:
Techniques to generate global tone-mapping operators (G-TMOs) that, when applied to high dynamic range images, visually approximate the use of spatially varying tone-mapping operators (SV-TMOs) are described. The disclosed G-TMOs provide substantially the same visual benefits as SV-TMOs but do not suffer from spatial artifacts such as halos and are, in addition, computationally efficient compared to SV-TMOs. In general, G-TMOs may be identified based on application of a SV-TMO to a down-sampled version of a full-resolution input image (e.g., a thumbnail). An optimized mapping between the SV-TMO's input and output constitutes the G-TMO. It has been unexpectedly discovered that when optimized (e.g., to minimize the error between the SV-TMO's input and output), G-TMOs so generated provide an excellent visual approximation to the SV-TMO (as applied to the full-resolution image).
Abstract:
Techniques to generate global tone-mapping operators (G-TMOs) that, when applied to high dynamic range images, visually approximate the use of spatially varying tone-mapping operators (SV-TMOs) are described. The disclosed G-TMOs provide substantially the same visual benefits as SV-TMOs but do not suffer from spatial artifacts such as halos and are, in addition, computationally efficient compared to SV-TMOs. In general, G-TMOs may be identified based on application of a SV-TMO to a down-sampled version of a full-resolution input image (e.g., a thumbnail). An optimized mapping between the SV-TMO's input and output constitutes the G-TMO. It has been unexpectedly discovered that when optimized (e.g., to minimize the error between the SV-TMO's input and output), G-TMOs so generated provide an excellent visual approximation to the SV-TMO (as applied to the full-resolution image).
Abstract:
Systems, methods, and computer readable media to approximate edge-preserving transformations with global transfer functions are described. In general, a first transfer function that approximates an edge-preserving operation can be found which, together with an enhancement filter (e.g., dynamic range compression) may be used to generate a global transfer function. Alternatively, a second transfer function may be found that approximates the behavior of the combined first transfer function and enhancement filter. Together the first and second transfer functions may generate a global transfer function. It has been determined that a down-sampled version of an input image may be used to develop the global transfer function. Application of global transfer functions in accordance with this disclosure can generate an output image that exhibits the same overall tonality of the input image without introducing the loss of detail and other artifacts attributable to local processing (e.g., the application of edge-preserving filters).