The general solution to HDR rendering
Our High-Dynamic-Range (HDR) world is the result of nonuniform illumination. We like to believe that 21st century
technology makes it possible to accurately reproduce any scene. On further study, we find that scene rendition remains a
best compromise. Despite all the remarkable accomplishments in digital imaging, we cannot capture and reproduce the
light in the world exactly. With still further study, we find that accurate reproduction is not necessary. We need an
interdisciplinary study of image making - painting, photography and image processing - to find the general solution.
HDR imaging would be very confusing, without two observations that resolve many paradoxes. First, optical veiling
glare, that depends on the scene content, severely limits the range of light on cameras' sensors, and on retinas. Second,
the neural spatial image processing in human vision counteracts glare with variable scene dependent responses. The
counter actions of these optical and neural processes shape the goals of HDR imaging. Successful HDR increases the
apparent contrast of details lost in the shadows and highlights of conventional images. They change the spatial
relationships by altering the local contrast of edges and gradients. The goal of HDR imaging is displaying calculated
appearance, rather than accurate light reproduction. By using this strategy we can develop universal algorithms that
process all images, LDR and HDR, achromatic and color, by mimicking human vision. The study of the general solution
for HDR imaging incorporates painting photography, vision research, color constancy and digital image processing.