Intel Patent | Light Source Estimation

Patent: Light Source Estimation

Publication Number: 20190005677

Publication Date: 2019-01-03

Applicants: Intel

Abstract

A method and apparatus for light source estimation are disclosed. In one embodiment, the apparatus comprises: an on-board tracking device to obtain a position and an orientation of a mobile device at a number of different times; one or more image sensors of the mobile device operable to capture a plurality of light probes of a scene from different positions and orientations at the number of different times; and a light source position determination processor coupled to receive the plurality of light probes and the position and orientation of the mobile device and operable to determine positions of discreet light sources of the scene using the plurality of light probes and the position and orientation of the mobile device.

Background

Recently produced algorithms and software may be used to render synthetic objects into real-world scenes. Oftentimes, a piece of furniture, a prop, a digital creature or an actor needs to be rendered seamlessly into a real scene. This task requires that the objects be lit consistently with the surfaces in their vicinity, and that the interplay of light between the objects and their surroundings be properly simulated.

One technique for rendering synthetic objects into scenes uses high dynamic range images and allows measurements of scene radiance to be derived from a set of differently exposed images. The technique allows both low levels of indirect radiance from surfaces and high levels of direct radiance from light sources to be accurately recorded. When combined with image-based modeling and rendering techniques such as view interpolation, projective texture mapping, and possibly active techniques for measuring geometry, these derived radiance maps can be used to construct spatial representations of scene radiance. However, one problem with such a technique is that the light information is captured for a room in separate steps from light probing devices (e.g., digital single-lens reflex(DSLR) cameras) and then requires offline processing.

Mobile devices have been used to capture light information. However, such mobile devices have only been used to capture very rough ambient light at the position of the mobile device which is used, for example, to color-balance the built-in camera of the mobile device. This approach does not cope with more challenging situations like mixed lighting.