A realistic camera model for computer graphics

Abstract

Most recent rendering research has concentrated on two subproblems: modeling the reflection of light from materials, and calculating the direct and indirect illumination from light sources and other surfaces. Another key component of a rendering system is the camera model. Unfortunately, current camera models are not geometrically or radiometrically correct and thus are not sufficient for synthesizing images from physically-based rendering programs.In this paper we describe a physically-based camera model for computer graphics. More precisely, a physically-based camera model accurately computes the irradiance on the film given the incoming radiance from the scene. In our model a camera is described as a lens system and film backplane. The lens system consists of a sequence of simple lens elements, stops and apertures. The camera simulation module computes the irradiance on the backplane from the scene radiances using distributed ray tracing. This is accomplished by a detailed simulation of the geometry of ray paths through the lens system, and by sampling the lens system such that the radiometry is computed accurately and efficiently. Because even the most complicated lenses have a relatively small number of elements, the simulation only increases the total rendering time slightly.

Camera Models and Optical Systems Used in Computer Graphics: Part II, Image-Based Techniques

“…The principal planes are usually determined by tracing rays through the lens system, although they can also be calculated analytically using lens thickness formulas [10]. Once we know the location of the principal planes and focal lengths, we can determine image formation through the lens.…”

“…Kolb et al [10] argued that the previous idealized models cannot accurately simulate the behavior of particular physical optical systems. They developed a stops aperture stop lenses optical axis exit pupil film plane rendering technique based on a physically-based camera model that simulated a system of lenses (Figure 4).…”

“…(Left image courtesy of Robert L. Cook [5]. Center and right images courtesy of Craig E. Kolb [10]. All images c 1995 ACM, Inc. Reprinted by permission.…”

“…Although this simple model generates photographic-like effects, Kolb et al [10] argued that the model is not precise enough to accurately approximate specific physical optical systems. They proposed a similar distributed ray tracing technique that traces rays directly through systems of lenses (a similar rendering model was subsequently described by Barsky et al [2] for a broader set of applications).…”

Camera Models and Optical Systems Used in Computer Graphics: Part I, Object-Based Techniques

“…This method is compatible with stratified sampling techniques and converges to the analytic model of a scene. Kolb et al [10] used a stratified strategy based on a mapping of concentric squares to concentric circles.…”