envyLight : an interface for editing natural illumination

Scenes lit with high dynamic range environment maps of real-world environments exhibit all the complex nuances of natural illumination. For applications that need lighting adjustments to the rendered images, editing environment maps directly is still cumbersome. First, designers have to determine which region in the environment map is responsible for the specific lighting feature (e.g. diffuse gradients, highlights and shadows) they desire to edit. Second, determining the parameters of image-editing operations needed to achieve specific changes to the selected lighting feature requires extensive trial-and-error. This paper presents envyLight, an interactive interface for editing natural illumination that combines an algorithm to select environment map regions, by sketching strokes on lighting features in the rendered image, with a small set of editing operations to quickly adjust the selected feature. The envyLight selection algorithm works well for indoor and outdoor lighting corresponding to rendered images where lighting features vary widely in number, size, contrast and edge blur. Furthermore, envyLight selection is general with respect to material type, from matte to sharp glossy, and the complexity of scenes' shapes. envyLight editing operations allow designers to quickly alter the position, contrast and edge blur of the selected lighting feature and can be keyframed to support animation.