What is Lightbrush?

Lightbrush™ is a software platform that allows artists, photographers, scientists, and developers to independently edit the surface colors and illumination of real-world imagery, as if manipulating a rendered 3D model of the world. Lightbrush generates production-quality, high-resolution Intrinsic Images which give users the ability to make edits that are challenging or
impossible to do with other software.

Lightbrush Cloud™ is a web application

What are illumination and reflectance?

A digital image is a measurement of the light reflected from objects in a scene. Each pixel represents a combination of the light falling on an object, the illumination, and the color and properties of the object itself, its reflectance. Lightbrush separates an image into these intrinsic components of illumination and reflectance.

The illumination map displays the color and intensity of the light falling on each surface in the scene. It is useful for manipulating the illumination in a scene, for example by adding or removing a shadow, changing the illumination color, or brightening the shadows.

The reflectance map shows the inherent color and albedo of each surface in the scene. It is useful for creating texture maps, manipulating the color of objects, or selecting and rotoscoping objects in a scene with complex illumination.

How Does Lightbrush Work?

Since the first time light was captured on chemical media, photographers have manipulated the lighting, subjects, and objects within scenes to create desired effects. For almost as long, photographers have manipulated the development of their images in creative ways to repair, enhance, or improve their photographs. No matter how creative they have been, however, they have never been able to directly manipulate the fundamental elements of a scene after the photograph was taken.

Tandent’s Trillien™ technology, which sits at the core of Lightbrush, offers a new way of thinking about images and image manipulation. Using a single digital photograph (A), it is able to separate the image into its intrinsic components: the illumination map (B) and the reflectance map (C). The illumination map shows the color and intensity of light illuminating each surface in the scene. The illumination is modulated by shadows, where a light source is blocked; shading, as the geometry of the surface changes; and interreflection, where light bounces off one object onto another. The reflectance map shows the effects of the material color and surface properties on a light source, no matter what the light source is. An orange reflects less blue light and more red light, for example, independent of the color of the illumination. The reflectance map shows the image as it would appear assuming a constant, even illumination on all portions of the image.

Multiplying the illumination map and the reflectance map recreates the original image. Therefore, the separation process does not create or remove information; it separates the original image into its component parts.

For the photographer, manipulating the illumination map is like being able to go back to the scene and change the light source position, intensity, or quality.

Manipulating the reflectance map allows the user to change the color of objects, their intensity, or their surface properties. By providing independent access to both illumination and reflectance, Lightbrush enables artists to make natural scene manipulations of digital images.