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Réseau Plate
A Réseau plate is a transparent sheet of glass or plastic engraved with a grid of crosshatches called fiducial markers. It was commonly used in film cameras (before the advent of digital media) for scientific and technical photography. The plate is placed at the focal plane of the camera just in front of the film. When the frame is exposed the fiducial markers scatter incoming light, creating a permanent shadow on the negative. The fiducial markers on a Réseau plate are sometimes called reticles. The Latin root of fiducial means ''trust, confidence''; fiducial markers are trustworthy reference points. The Latin root of reticle means ''small meshwork bag, small net''; a grid of reticles has a net-like appearance. Purpose and function If the film negative is properly printed the fiducial markers will be evenly spaced on the positive image. Uneven spacing reveals that the image has been distorted. Identical spacing on adjacent images (e.g. from a series of aerial photos) ensures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fiducial Marker
A fiducial marker or fiducial is an object placed in the field of view of an imaging system that appears in the image produced, for use as a point of reference or a measure. It may be either something placed into or on the imaging subject, or a mark or set of marks in the reticle of an optical instrument. Applications Microscopy In high-resolution optical microscopy, fiducials can be used to actively stabilize the field of view. Stabilization to better than 0.1 nm is achievable. Physics In physics, 3D computer graphics, and photography, fiducials are reference points: fixed points or lines within a scene to which other objects can be related or against which objects can be measured. Cameras outfitted with Réseau plates produce these reference marks (also called Réseau crosses) and are commonly used by NASA. Such marks are closely related to the timing marks used in optical mark recognition. Geographical survey Airborne geophysical surveys also use the term "fiducial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photographic Printing
Photographic printing is the process of producing a final image on paper for viewing, using chemically sensitized paper. The paper is exposed to a photographic negative, a positive transparency (or ''slide''), or a digital image file projected using an enlarger or digital exposure unit such as a LightJet or Minilab printer. Alternatively, the negative or transparency may be placed atop the paper and directly exposed, creating a contact print. Digital photographs are commonly printed on plain paper, for example by a color printer, but this is not considered "photographic printing". Following exposure, the paper is processed to reveal and make permanent the latent image. Printing on black-and-white paper The process consists of four major steps, performed in a photographic darkroom or within an automated photo printing machine. These steps are: *Exposure of the image onto the sensitized paper using a contact printer or enlarger; * Processing of the latent image using t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photogrammetry
Photogrammetry is the science and technology of obtaining reliable information about physical objects and the environment through the process of recording, measuring and interpreting photographic images and patterns of electromagnetic radiant imagery and other phenomena. The term photogrammetry was coined by the Prussian architect Albrecht Meydenbauer, which appeared in his 1867 article "Die Photometrographie." There are many variants of photogrammetry. One example is the extraction of three-dimensional measurements from two-dimensional data (i.e. images); for example, the distance between two points that lie on a plane parallel to the photographic image plane can be determined by measuring their distance on the image, if the scale of the image is known. Another is the extraction of accurate color ranges and values representing such quantities as albedo, specular reflection, metallicity, or ambient occlusion from photographs of materials for the purposes of physically based ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hasselblad Lunar Surface Data Camera
Victor Hasselblad AB is a Swedish manufacturer of medium format cameras, photographic equipment and image scanners based in Gothenburg, Sweden. The company originally became known for its classic analog medium-format cameras that used a waist-level viewfinder. Perhaps the most famous use of the Hasselblad camera was during the Apollo program missions when the first humans landed on the Moon. Almost all of the still photographs taken during these missions used modified Hasselblad cameras. In 2016, Hasselblad introduced the world's first digital compact mirrorless medium-format camera, the X1D-50c, changing the portability of medium-format photography. Hasselblad produces about 10,000 cameras a year from a small three-storey building. Company history The company was established in 1841 in Gothenburg, Sweden, by Fritz Wiktor Hasselblad, as a trading company, F. W. Hasselblad and Co. The founder's son, Arvid Viktor Hasselblad, was interested in photography and started the pho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angular Distance
Angular distance \theta (also known as angular separation, apparent distance, or apparent separation) is the angle between the two sightlines, or between two point objects as viewed from an observer. Angular distance appears in mathematics (in particular geometry and trigonometry) and all natural sciences (e.g. astronomy and geophysics). In the classical mechanics of rotating objects, it appears alongside angular velocity, angular acceleration, angular momentum, moment of inertia and torque. Use The term ''angular distance'' (or ''separation'') is technically synonymous with ''angle'' itself, but is meant to suggest the linear distance between objects (for instance, a couple of stars observed from Earth). Measurement Since the angular distance (or separation) is conceptually identical to an angle, it is measured in the same units, such as degrees or radians, using instruments such as goniometers or optical instruments specially designed to point in well-defined directions and re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photography Equipment
Photography is the art, application, and practice of creating durable images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is employed in many fields of science, manufacturing (e.g., photolithography), and business, as well as its more direct uses for art, film and video production, recreational purposes, hobby, and mass communication. Typically, a lens is used to focus the light reflected or emitted from objects into a real image on the light-sensitive surface inside a camera during a timed exposure. With an electronic image sensor, this produces an electrical charge at each pixel, which is electronically processed and stored in a digital image file for subsequent display or processing. The result with photographic emulsion is an invisible latent image, which is later chemically "developed" into a visible image, either negative or positive, depending on the purpo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
