📑 Table of Contents▼
A Ronchi ruling

A Ronchi ruling, Ronchi grating, or Ronchi mask, named after the Italian physicist Vasco Ronchi,[1] is a constant-interval bar and space square-wave optical target or mask. The design produces a precisely patterned light source by reflection or illumination, or a stop pattern by transmission, with precise uniformity, spatial frequency, sharp edge definition, and high contrast ratio.

Manufacturing

edit

Ronchi rulings are typically manufactured through photolithographic deposition of metallic chromium on a substrate, which yields a precise, nearly 100% contrast pattern. For a reflective or illuminated type, dark stripes are printed on a diffusely reflecting or translucent substrate, such as a square of white ceramic material or opal glass. For a transmissive type, opaque stripes are printed on a transparent glass substrate. A transmissive type may be readily modified to act as an illuminated type by stacking a reflective object behind it.

Applications

edit

A test target in the Ronchi pattern provides a precise signal for testing resolution, contrast, distortion, aberrations, and diffraction in optical imaging systems.[2] In constructing telescope mirrors, the Ronchi test procedure evaluates the quality of the surface figure and provides guidance on refining the figure. The ruled divisions in a linear encoder are in the form of Ronchi ruling, which provides the basic precision of the measurements.

A single Ronchi device provides a pattern that is periodic in one dimension. Stacking a pair of Ronchi transmission elements produces a two-dimensional array of periodic rectangular or rhomboidal apertures. By varying the translation, rotation, and chosen frequency of one element against the other, a wide assortment of laboratory test patterns can be generated with the paired arrangement.

Telescopic focusing aids such as the Bahtinov mask consist of multiple adjacent Ronchi transmission stop patterns. Inserting a Ronchi mask in the entrance aperture produces diffraction effects in the image, which visibly change with the focusing condition.

See also

edit

References

edit
  1. ^ Chris Plicht. "Ronchi, Vasco (1897–1988)". Plichts Website.
  2. ^ "Testing and Targets". Edmund Optics Imaging Resource Guide. Retrieved October 2, 2018.

📚 Artikel Terkait di Wikipedia

Ronchi

condition Ronchi test, a method of determining the figure of a mirror used in telescopes and other optical devices, invented by Vasco Ronchi Ronchi ruling, a

1951 USAF resolution test chart

full series. Each element consists of three bars which form a minimal Ronchi ruling. These 54 elements are provided in a standardized series of logarithmic

Vasco Ronchi

equipment. The Ronchi test is widely used in amateur telescope making. The Ronchi ruling also bears his name. He served numerous terms as the President of the

Square wave (waveform)

Sine wave Triangle wave Sawtooth wave Waveform Sound Multivibrator Ronchi ruling, a square-wave stripe target used in imaging. Cross sea Clarinet, a

List of eponyms (L–Z)

Romulus, Roman mythological character – Rome. Vasco Ronchi, Italian physicist – Ronchi test, Ronchi ruling. Pierre de Ronsard, French poet – Rosa 'Eden'. Wilhelm

Halftone

plate. Other techniques used a "screen" consisting of parallel bars (a Ronchi ruling), which was then combined with a second exposure with the same screen

Bahtinov mask

frame shows a focus difference of 140.6 μm. Carey mask Hartmann mask Ronchi ruling Pavel Bahtinov (22 September 2005). "Optional Focusing Mask". Retrieved

81st Venice International Film Festival

It Takes Special Mention: The cast of Familia (Francesco Gheghi, Barbara Ronchi, Francesco Di Leva and Marco Cicalese) Vermiglio by Maura Delpero I'm Still