Lightfield measurements - historical

Prior to Edward Adelson and John Wang’s 1992 work introducing the single-lens plenoptic camera, the concepts and methods for measuring the light field emerged along three historical tracks:

  1. Theoretical radiometry of environmental light fields
  2. Ray-slope and optical wavefront sensing in astronomy
  3. Directional photography and microlens imaging in optics

1. Environmental Light Fields (Radiometry & Light Flow)

If you are looking for the earliest mathematical and physical treatment of measuring and describing the distribution of light rays throughout free space and environments:

Alexander (Andrey) Gershun (1936 / 1939)

  • The Contribution: Gershun was a Soviet physicist who formalized the modern concept and coined the term “light field” (Svetovoe Pole). He defined the light field as the total spatial distribution of radiant flux in 3D space, parameterized by position \((x, y, z)\) and ray direction \((\theta, \phi)\). He established the vector calculus and geometric formalism describing how light rays transfer through natural environments and interact with surfaces.
  • Key References:
  • Gershun, A. (1936). Svetovoe Pole [The Light Field]. Moscow: ONTI.
  • Gershun, A. (1939). The light field (P. Moon & G. Timoshenko, Trans.). Journal of Mathematics and Physics, 18(1–4), 51–151.

2. Ray-Slope and Optical Light Field Sensing in Astronomy

Astronomers were among the first to devise instruments that sample ray angles at discrete spatial coordinates across an aperture:

Johannes Franz Hartmann (1900 / 1904)

  • The Contribution: Hartmann developed the Hartmann Screen Test (or Hartmann Mask) to measure optical aberrations and ray trajectories in large astronomical refractors and reflectors. By placing an opaque mask containing a regular grid of sub-apertures (pinholes) over the entrance pupil of a telescope, Hartmann isolated individual ray bundles across coordinates \((u, v)\) and measured their transverse deflections \((x, y)\) on photographic plates placed inside and outside of focus. This directly sampled the 4D ray space (the optical light field) of the telescope pupil.
  • Key Reference:
  • Hartmann, J. (1904). Bemerkungen über den Bau und die Justirung von Grossen Refractoren [Remarks on the construction and adjustment of large refractors]. Zeitschrift für Instrumentenkunde, 24, 1–21; 33–47.

Roland V. Shack & Ben C. Platt (1971)

  • The Contribution: At the University of Arizona Optical Sciences Center, Shack and Platt updated Hartmann’s concept by replacing the light-blocking hole array with a monolithic microlens (lenslet) array, inventing the Shack-Hartmann Wavefront Sensor.
  • Astronomical Application: Developed originally to measure atmospheric turbulence for military and astronomical imaging systems, the sensor maps local ray slopes \((u, v)\) to spot displacements on a sensor array \((x, y)\). This device is geometrically identical to the optical layout Adelson and Wang later applied to computer vision.
  • Key Reference:
  • Shack, R. V., & Platt, B. C. (1971). Production and use of a lenticular plate array for wavefront sensing. Journal of the Optical Society of America, 61(5), 656.

3. Microlens Light Field Capture in Optics & Photography

In classical optics, researchers used microlens arrays to capture the directional distribution of light for 3D image reconstruction:

Gabriel Lippmann (1908)

  • The Contribution: Nobel laureate Gabriel Lippmann invented Integral Photography (photographie intégrale). He proposed placing an array of minute convex lenses (a fly’s-eye lenslet array) directly on a photographic emulsion. Each microlens recorded a distinct sub-image corresponding to different viewing perspectives of the scene.
  • Key Reference:
  • Lippmann, G. (1908). Épreuves réversibles: photographies intégrales. Comptes Rendus de l’Académie des Sciences, 146(9), 446–451.

Herbert E. Ives (1928 / 1930)

  • The Contribution: Ives extended parallax stereography and Lippmann’s integral photography to continuous parallax panoramagrams using lenticular sheet arrays and large-aperture camera objectives.
  • Ives, H. E. (1928). Camera for making parallax panoramagrams. Journal of the Optical Society of America, 17(6), 435–439.

Summary of Historical Connections to Adelson & Wang (1992)

  • Gershun (1936) formalized the radiometric concept of the light field.
  • Hartmann (1900) and Shack & Platt (1971) created the measurement hardware using aperture masks and microlens arrays to resolve ray angles across pupil positions.
  • Lippmann (1908) pioneered using lenslet arrays to record directional light information on an image sensor.
  • Adelson & Bergen (1991) synthesized these ideas into the plenoptic function, and Adelson & Wang (1992) placed a microlens array at the focal plane of a camera lens to extract disparity and depth for computer vision.