|
Collimating Lens
A collimator is a device which narrows a beam of particles or waves. To narrow can mean either to cause the directions of motion to become more aligned in a specific direction (i.e., make collimated light or parallel rays), or to cause the spatial cross section of the beam to become smaller (beam limiting device). History The English physicist Henry Kater was the inventor of the floating collimator, which rendered a great service to practical astronomy. He reported about his invention in January 1825. In his report, Kater mentioned previous work in this area by Carl Friedrich Gauss and Friedrich Bessel. Optical collimators In optics, a collimator may consist of a curved mirror or lens with some type of light source and/or an image at its focus. This can be used to replicate a target focused at infinity with little or no parallax. In lighting, collimators are typically designed using the principles of nonimaging optics. Optical collimators can be used to calibrate other optic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CRC Press
The CRC Press, LLC is an American publishing group that specializes in producing technical books. Many of their books relate to engineering, science and mathematics. Their scope also includes books on business, forensics and information technology. CRC Press is now a division of Taylor & Francis, itself a subsidiary of Informa. History The CRC Press was founded as the Chemical Rubber Company (CRC) in 1903 by brothers Arthur, Leo and Emanuel Friedman in Cleveland, Ohio, based on an earlier enterprise by Arthur, who had begun selling rubber laboratory aprons in 1900. The company gradually expanded to include sales of laboratory equipment to chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a graduated scientist trained in the study of chemistry, or an officially enrolled student in the field. Chemists study the composition of ...s. In 1913 the CRC offered a short (116-page) manual called the ''Rubber Handboo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laser Diode
file:Laser diode chip.jpg, The laser diode chip removed and placed on the eye of a needle for scale A laser diode (LD, also injection laser diode or ILD or semiconductor laser or diode laser) is a semiconductor device similar to a light-emitting diode in which a diode pumped directly with electrical current can create active laser medium, lasing conditions at the diode's p–n junction, junction. Driven by voltage, the doped p–n-transition allows for carrier generation and recombination, recombination of an electron with a electron hole, hole. Due to the drop of the electron from a higher energy level to a lower one, radiation is generated in the form of an emitted photon. This is spontaneous emission. Stimulated emission can be produced when the process is continued and further generates light with the same phase, coherence, and wavelength. The choice of the semiconductor material determines the wavelength of the emitted beam, which in today's laser diodes range from the inf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflector Sight
A reflector sight or reflex sight is an optical sight that allows the user to look through a partially reflecting glass element and see an aiming point or some image (helping to aim the device, to which the sight is attached, on the target) superimposed on the field of view. These sights work on the simple optical principle that anything (such as an illuminated reticle) at the focus of a lens or curved mirror will appear to be sitting in front of the viewer at infinity. Reflector sights employ some form of "reflector" to allow the viewer to see the infinity image and the field of view at the same time, either by bouncing the image created by lens off a slanted glass plate, or by using a mostly clear curved glass reflector that images the reticle while the viewer looks through the reflector. Since the reticle image is at infinity, it stays in alignment with the device to which the sight is attached regardless of the viewer's eye position to the sight, removing most of the parallax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field Of View
The field of view (FOV) is the angle, angular extent of the observable world that is visual perception, seen at any given moment. In the case of optical instruments or sensors, it is a solid angle through which a detector is sensitive to electromagnetic radiation. It is further relevant in ''angle of view, photography''. Humans and animals In the context of human and primate vision, the term "field of view" is typically only used in the sense of a restriction to what is visible by external apparatus, like when wearing spectacles or virtual reality goggles. Note that eye movements are allowed in the definition but do not change the field of view when understood this way. If the analogy of the eye's retina working as a sensor is drawn upon, the corresponding concept in human (and much of animal vision) is the visual field. It is defined as "the number of degrees of visual angle during stable fixation of the eyes".Strasburger, Hans; Pöppel, Ernst (2002). Visual Field. In G. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beam Splitter
A beam splitter or beamsplitter is an optical instrument, optical device that splits a beam of light into a transmitted and a reflected beam. It is a crucial part of many optical experimental and measurement systems, such as Interferometry, interferometers, also finding widespread application in fibre optic telecommunications. Designs In its most common form, a cube, a beam splitter is made from two triangular glass prism (optics), prisms which are glued together at their base using polyester, epoxy, or urethane-based adhesives. (Before these synthetic resins, natural ones were used, e.g. Canada balsam.) The thickness of the resin layer is adjusted such that (for a certain wavelength) half of the light incident through one "port" (i.e., face of the cube) is reflection (physics), reflected and the other half is transmitted due to Total internal reflection#Frustrated_TIR, FTIR (frustrated total internal reflection). polarizer, Polarizing beam splitters, such as the Wollaston prism ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reticle
A reticle or reticule, also known as a graticule or crosshair, is a pattern of fine lines or markings built into the eyepiece of an optical device such as a telescopic sight, spotting scope, theodolite, optical microscope or the electronic visual display, screen of an oscilloscope, to provide frame of reference, measurement references during visual inspections. Today, engraved lines or embedded fibers may be replaced by a digital image superimposed on a screen or eyepiece. Both terms may be used to describe any set of patterns used for aiding visual measurements and calibrations, but in modern use ''reticle'' is most commonly used for weapon sight (device), sights, while ''graticule'' is more widely used for non-weapon measuring instruments such as oscilloscope#Graticule, oscilloscope display, astronomic telescopes, microscopes and microscope slide, slides, surveying instruments and other similar devices. There are many variations of reticle pattern; this article concerns its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collimator Sight
A collimator sight is a type of optical sight that allows the user looking into it to see an illuminated aiming point aligned with the device the sight is attached to, regardless of eye position (with little parallax). They are also referred to as collimating sights or "occluded eye gunsight" (OEG). Description The basic layout of a collimator sight is a closed tube with a lens at its open end and a luminous reticle mounted near the closed end at the focus of the lens, creating an optical collimator. The reticle is illuminated by an electronic light source (an incandescent light bulb or, more recently, a light-emitting diode) or by ambient light gathered behind the reticle via an opalescent window or fiber optic light pipe. Collimator sights are a relatively old idea, being used in many forms for almost 100 years. Usage Collimator sights, also known as occluded eye gunsights (OEGs), are designed for use with both eyes open. The user aligns one eye with the sight while the o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gun Sight
A sight or sighting device is any device used to assist in precise visual alignment (i.e. ''aiming'') of weapons, surveying instruments, aircraft equipment, optical illumination equipment or larger optical instruments with the intended target. Sights can be a simple set or system of physical markers that serve as visual references for directly aligning the user's line of sight with the target (such as iron sights on firearms), or optical instruments that provide an optically enhanced—often magnified—target image aligned in the same focus with an aiming point (e.g. telescopic, reflector and holographic sights). There are also sights that actively project an illuminated point of aim (a.k.a. "hot spot") onto the target itself so it can be observed by anyone with a direct view, such as laser sights and infrared illuminators on some night vision devices, as well as augmented or even virtual reality-enabled digital cameras ("smart scopes") with software algorithms that produce ... [...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. While the invention of the method is attributed to Aimé Laussedat, the term "photogrammetry" was coined by the German architect , 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 (map), scale of the image is known. Another is the extraction of accurate color ranges and values representing such quantities as albedo, specular reflection, Metallicity#Photometric colors, metallicity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fiduciary Marker
A fiducial marker or fiducial is an object placed in the field of view of an image 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" as a sequential reference number in the mea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sight (device)
A sight or sighting device is any gadget, device used to assist in precise visual perception, visual alignment (i.e. ''aiming'') of weapons, surveying instruments, aircraft equipment, optical illumination equipment or larger optical instruments with the intended target. Sights can be a simple set or system of physical markers that serve as visual references for directly aligning the user's line of sight with the target (such as iron sights on firearms), or optical instruments that provide an optically enhanced—often magnification, magnified—target image aligned in the same focus (optics), focus with an aiming point (e.g. telescopic sight, telescopic, reflector sight, reflector and holographic sights). There are also sights that actively project an illuminated point of aim (a.k.a. "hot spot") onto the target itself so it can be observed by anyone with a direct view, such as laser sight (firearms), laser sights and infrared illuminators on some night vision devices, as well as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
