A refracting telescope is a type of optical telescope that uses a lens as its objective to form an image. The refracting telescope design was used in spy glasses and astronomical telescopes but is used for long focus camera lenses. Although large refracting telescopes were popular in the second half of the 19th century, for most research purposes the refracting telescope has been superseded by the reflecting telescope which allows larger apertures. A refractor's magnification is calculated by dividing the focal length of the objective lens by that of the eyepiece. Refractors were the earliest type of optical telescope; the first practical refracting telescopes appeared in the Netherlands about 1608, were credited to three individuals, Hans Lippershey and Zacharias Janssen, spectacle-makers in Middelburg, Jacob Metius of Alkmaar. Galileo Galilei, happening to be in Venice in about the month of May 1609, heard of the invention and constructed a version of his own. Galileo communicated the details of his invention to the public, presented the instrument itself to the Doge Leonardo Donato, sitting in full council.
All refracting telescopes use the same principles. The combination of an objective lens 1 and some type of eyepiece 2 is used to gather more light than the human eye is able to collect on its own, focus it 5, present the viewer with a brighter and magnified virtual image 6; the objective in a refracting telescope bends light. This refraction causes parallel light rays to converge at a focal point; the telescope converts a bundle of parallel rays to make an angle α, with the optical axis to a second parallel bundle with angle β. The ratio β/α is called the angular magnification, it equals the ratio between the retinal image sizes obtained without the telescope. Refracting telescopes can come in many different configurations to correct for image orientation and types of aberration; because the image was formed by the bending of light, or refraction, these telescopes are called refracting telescopes or refractors. The design Galileo Galilei used in 1609 is called a Galilean telescope, it used a divergent eyepiece lens.
A Galilean telescope, because the design has no intermediary focus, results in a non-inverted and upright image. Galileo's best telescope magnified objects about 30 times; because of flaws in its design, such as the shape of the lens and the narrow field of view, the images were blurry and distorted. Despite these flaws, the telescope was still good enough for Galileo to explore the sky; the Galilean telescope could view the phases of Venus, was able to see craters on the Moon and four moons orbiting Jupiter. Parallel rays of light from a distant object would be brought to a focus in the focal plane of the objective lens; the eyepiece lens renders them parallel once more. Non-parallel rays of light from the object traveling at an angle α1 to the optical axis travel at a larger angle after they passed through the eyepiece; this leads to an increase in the apparent angular size and is responsible for the perceived magnification. The final image is a virtual image, is the same way up as the object.
The Keplerian telescope, invented by Johannes Kepler in 1611, is an improvement on Galileo's design. It uses a convex lens as the eyepiece instead of Galileo's concave one; the advantage of this arrangement is that the rays of light emerging from the eyepiece are converging. This allows for a much wider field of view and greater eye relief, but the image for the viewer is inverted. Higher magnifications can be reached with this design, but to overcome aberrations the simple objective lens needs to have a high f-ratio; the design allows for use of a micrometer at the focal plane. The achromatic refracting lens was invented in 1733 by an English barrister named Chester Moore Hall, although it was independently invented and patented by John Dollond around 1758; the design overcame the need for long focal lengths in refracting telescopes by using an objective made of two pieces of glass with different dispersion,'crown' and'flint glass', to limit the effects of chromatic and spherical aberration.
Each side of each piece is ground and polished, the two pieces are assembled together. Achromatic lenses are corrected to bring two wavelengths into focus in the same plane; the era of the'great refractors' in the 19th century saw large achromatic lenses culminating with the largest achromatic refractor built, the Great Paris Exhibition Telescope of 1900. Apochromatic refractors have objectives built with extra-low dispersion materials, they are designed to bring three wavelengths into focus in the same plane. The residual color error can be up than that of an achromatic lens; such telescopes contain elements of fluorite or special, extra-low dispersion glass in the objective and produce a crisp image, free of chromatic aberration. Due to the special materials needed in the fabrication, apochromatic refractors are more expensive than telescopes of other types with a comparable aperture. Refractors suffer from residual spherical aberration; this affects shorter focal ratios more than longer ones.
Anaglyph 3D is the name given to the stereoscopic 3D effect achieved by means of encoding each eye's image using filters of different colors red and cyan. Anaglyph 3D images contain two differently filtered colored images, one for each eye; when viewed through the "color-coded" "anaglyph glasses", each of the two images reaches the eye it's intended for, revealing an integrated stereoscopic image. The visual cortex of the brain fuses this into the perception of a three-dimensional scene or composition. Anaglyph images have seen a recent resurgence due to the presentation of images and video on the Web, Blu-ray Discs, CDs, in print. Low cost paper frames or plastic-framed glasses hold accurate color filters that after 2002, make use of all 3 primary colors; the current norm is cyan, with red being used for the left channel. The cheaper filter material used in the monochromatic past dictated red and blue for convenience and cost. There is a material improvement of full color images, with the cyan filter for accurate skin tones.
Video games, theatrical films, DVDs can be shown in the anaglyph 3D process. Practical images, for science or design, where depth perception is useful, include the presentation of full scale and microscopic stereographic images. Examples from NASA include Mars Rover imaging, the solar investigation, called STEREO, which uses two orbital vehicles to obtain the 3D images of the sun. Other applications include geological illustrations by the United States Geological Survey, various online museum objects. A recent application is for stereo imaging of the heart using 3D ultra-sound with plastic red/cyan glasses. Anaglyph images are much easier to view than either crossed-view pairs stereograms. However, these side-by-side types offer bright and accurate color rendering, not achieved with anaglyphs. Cross-view prismatic glasses with adjustable masking have appeared, that offer a wider image on the new HD video and computer monitors; the oldest known description of anaglyph images was written in August 1853 by W. Rollmann in Stargard about his "Farbenstereoscope".
He had the best results viewing a yellow/blue drawing with red/blue glasses. Rollmann found that with a red/blue drawing the red lines were not as distinct as yellow lines through the blue glass. In 1858, in France, Joseph D'Almeida delivered a report to l'Académie des sciences describing how to project three-dimensional magic lantern slide shows using red and green filters to an audience wearing red and green goggles. Subsequently he was chronicled as being responsible for the first realisation of 3D images using anaglyphs. Louis Ducos du Hauron produced the first printed anaglyphs in 1891; this process consisted of printing the two negatives which form a stereoscopic photograph on to the same paper, one in blue, one in red. The viewer would use colored glasses with red and blue or green; the left eye would see the blue image which would appear black, whilst it would not see the red. Thus a three dimensional image would result. William Friese-Green created the first three-dimensional anaglyphic motion pictures in 1889, which had public exhibition in 1893.
3-D films enjoyed something of a boom in the 1920s. The term "3-D" was coined in the 1950s; as late as 1954 films such as The Creature from the Black Lagoon were successful. Shot and exhibited using the Polaroid system, "The Creature from the Black Lagoon" was reissued much in an anaglyph format so it could be shown in cinemas without the need for special equipment. In 1953, the anaglyph had begun appearing in newspapers and comic books; the 3-D comic books were one of the most interesting applications of anaglyph to printing. Over the years, anaglyphic pictures have sporadically appeared in comics and magazine ads. Although not anaglyphic, Jaws 3-D was a box-office success in 1983. At present the excellent quality of computer displays and user-friendly stereo-editing programs offer new and exciting possibilities for experimenting with anaglyph stereo. A stereo pair is a pair of images from different perspectives at the same time. Objects closer to the camera have greater differences in appearance and position within the image frames than objects further from the camera.
Cameras captured two color filtered images from the perspective of the left and right eyes which were projected or printed together as a single image, one side through a red filter and the other side through a contrasting color such as blue or green or mixed cyan. As outlined below, one may now use an image processing computer program to simulate the effect of using color filters, using as a source image a pair of either color or monochrome images; this is called image stitching. In the 1970s filmmaker Stephen Gibson filmed direct anaglyph adult movies, his "Deep Vision" system replaced the original camera lens with two color-filtered lenses focused on the same film frame. In the 1980s, Gibson patented his mechanism. Many computer graphics programs provide the basic tools required to prepare anaglyphs from stereo pairs. In simple practice, the left eye image is filtered to remove green; the right eye image is filtered to remove red. The two images are positioned in the compositing phase in close overlay registration.
Plugins for some of these programs as well as programs dedicated to anaglyph preparation are available which automate the process and require the user to choose only a few basic
Dissection is the dismembering of the body of a deceased animal or plant to study its anatomical structure. Autopsy is used in forensic medicine to determine the cause of death in humans. Less extensive dissection of plants and smaller animals preserved in a formaldehyde solution is carried out or demonstrated in biology and natural science classes in middle school and high school, while extensive dissections of cadavers of adults and children, both fresh and preserved are carried out by medical students in medical schools as a part of the teaching in subjects such as anatomy and forensic medicine. Dissection is conducted in a morgue or in an anatomy lab. Dissection has been used for centuries to explore anatomy. Objections to the use of cadavers have led to the use of alternatives including virtual dissection of computer models. Plant and animal bodies are dissected to analyze the function of its components. Dissection is practised by students in courses of biology, botany and veterinary science, sometimes in arts studies.
In medical schools, students dissect human cadavers to learn anatomy. Dissection is used to help to determine the cause of death in autopsy and is an intrinsic part of forensic medicine. A key principle in the dissection of human cadavers is the prevention of human disease to the dissector. Prevention of transmission includes the wearing of protective gear, ensuring the environment is clean, dissection technique and pre-dissection tests to specimens for the presence of HIV and Hepatitis viruses. Specimens are dissected in morgues or anatomy labs; when provided, they are evaluated for use as a "fresh" or "prepared" specimen. A "fresh" specimen may be dissected within some days, retaining the characteristics of a living specimen, for the purposes of training. A "prepared" specimen may be preserved in solutions such as formalin and pre-dissected by an experienced anatomist, sometimes with the help of a diener; this preparation is sometimes called prosection. Most dissection involves the careful isolation and removal of individual organs, called the Virchow technique.
An alternative more cumbersome technique involves the removal of the entire organ body, called the Letulle technique. This technique allows a body to be sent to a funeral director without waiting for the sometimes time-consuming dissection of individual organs; the Rokitansky method involves an in situ dissection of the organ block, the technique of Ghon involves dissection of three separate blocks of organs - the thorax and cervical areas and abdominal organs, urogenital organs. Dissection of individual organs involves accessing the area in which the organ is situated, systematically removing the anatomical connections of that organ to its surroundings. For example, when removing the heart, connects such as the superior vena cava and inferior vena cava are separated. If pathological connections exist, such as a fibrous pericardium this may be deliberately dissected along with the organ. Human dissections were carried out by the Greek physicians Herophilus of Chalcedon and Erasistratus of Chios in the early part of the third century BC.
During this period, the first exploration into full human anatomy was performed rather than a base knowledge gained from'problem-solution' delving. While there was a deep taboo in Greek culture concerning human dissection, there was at the time a strong push by the Ptolemaic government to build Alexandria into a hub of scientific study. For a time, Roman law forbade dissection and autopsy of the human body, so physicians had to use other cadavers. Galen, for example, dissected the Barbary macaque and other primates, assuming their anatomy was the same as that of humans; the ancient societies that were rooted in India left behind artwork on how to kill animals during a hunt. The images showing how to kill most depending on the game being hunted relay an intimate knowledge of both external and internal anatomy as well as the relative importance of organs; the knowledge was gained through hunters preparing the captured prey. Once the roaming lifestyle was no longer necessary it was replaced in part by the civilization that formed in the Indus Valley.
There is little that remains from this time to indicate whether or not dissection occurred, the civilization was lost to the Aryan people migrating. Early in the history of India, the Arthashastra described the 4 ways that death can occur and their symptoms: drowning, strangling, or asphyxiation. According to that source, an autopsy should be performed in any case of untimely demise; the practice of dissection flourished during the 8th century. It was under their rule; this created a need to better understand human anatomy, so as to have educated surgeons. Dissection was limited by the religious taboo on cutting the human body; this changed the approach taken to accomplish the goal. The process involved the loosening of the tissues in streams of water before the outer layers were sloughed off with soft implements to reach the musculature. To perfect the technique of slicing, the prospective students used gourds and squash; these techniques of dissection gave rise to an advanced understanding of the anatomy and the enabled them to complete procedures used today, such as rhinoplasty.
During medieval times the anatomical teachings from India spread throughout the known world however the practice of dissection was stunted by Islam. The practice of dissection at a university level was not seen again until 1827, when it was performed by the student Pandit Madhusudan Gupta. Through the 1900s
Dark-field microscopy describes microscopy methods, in both light and electron microscopy, which exclude the unscattered beam from the image. As a result, the field around the specimen is dark. In optical microscopy, dark-field describes an illumination technique used to enhance the contrast in unstained samples, it works by illuminating the sample with light that will not be collected by the objective lens and thus will not form part of the image. This produces the classic appearance of a dark black, background with bright objects on it; the steps are illustrated in the figure. Light enters the microscope for illumination of the sample. A specially sized disc, the patch stop, blocks some light from the light source, leaving an outer ring of illumination. A wide phase annulus can be reasonably substituted at low magnification; the condenser lens focuses the light towards the sample. The light enters the sample. Most is directly transmitted; the scattered light enters the objective lens, while the directly transmitted light misses the lens and is not collected due to a direct-illumination block.
Only the scattered light goes on to produce the image, while the directly transmitted light is omitted. Dark-field microscopy is a simple yet effective technique and well suited for uses involving live and unstained biological samples, such as a smear from a tissue culture or individual, water-borne, single-celled organisms. Considering the simplicity of the setup, the quality of images obtained from this technique is impressive; the main limitation of dark-field microscopy is the low light levels seen in the final image. This means that the sample must be strongly illuminated, which can cause damage to the sample. Dark-field microscopy techniques are entirely free of artifacts, due to the nature of the process. However, the interpretation of dark-field images must be done with great care, as common dark features of bright-field microscopy images may be invisible, vice versa. While the dark-field image may first appear to be a negative of the bright-field image, different effects are visible in each.
In bright-field microscopy, features are visible where either a shadow is cast on the surface by the incident light or a part of the surface is less reflective by the presence of pits or scratches. Raised features that are too smooth to cast shadows will not appear in bright-field images, but the light that reflects off the sides of the feature will be visible in the dark-field images. Comparison of transillumination techniques used to generate contrast in a sample of tissue paper Dark-field microscopy has been used in computer mouse pointing devices, in order to allow an optical mouse to work on transparent glass by imaging microscopic flaws and dust on its surface; when coupled to hyperspectral imaging, dark-field microscopy becomes a powerful tool for the characterization of nanomaterials embedded in cells. In a recent publication, Patskovsky et al. used this technique to study the attachment of gold nanoparticles targeting CD44+ cancer cells. Dark-field studies in transmission electron microscopy play a powerful role in the study of crystals and crystal defects, as well as in the imaging of individual atoms.
Imaging involves tilting the incident illumination until a diffracted, rather than the incident, beam passes through a small objective aperture in the objective lens back focal plane. Dark-field images, under these conditions, allow one to map the diffracted intensity coming from a single collection of diffracting planes as a function of projected position on the specimen and as a function of specimen tilt. In single-crystal specimens, single-reflection dark-field images of a specimen tilted just off the Bragg condition allow one to "light up" only those lattice defects, like dislocations or precipitates, that bend a single set of lattice planes in their neighborhood. Analysis of intensities in such images may be used to estimate the amount of that bending. In polycrystalline specimens, on the other hand, dark-field images serve to light up only that subset of crystals that are Bragg-reflecting at a given orientation. Weak-beam imaging involves optics similar to conventional dark-field, but use of a diffracted beam harmonic rather than the diffracted beam itself.
Much higher resolution of strained regions around defects can be obtained in this way. Annular dark-field imaging requires one to form images with electrons diffracted into an annular aperture centered on, but not including, the unscattered beam. For large scattering angles in a scanning transmission electron microscope, this is sometimes called Z-contrast imaging because of the enhanced scattering from high-atomic-number atoms; this a mathematical technique intermediate between direct and reciprocal space for exploring images with well-defined periodicities, like electron microscope lattice-fringe images. As with analog dark-field imaging in a transmission electron microscope, it allows one to "light up" those objects in the field of view where periodicities of interest reside. Unlike analog dark-field imaging it may allow one to map the Fourier-phase of periodicities, hence phase gradients, which provide quantitative information on vector lattice strain. Annular dark-field imaging Light field microscopy Wavelets Nikon - Stereomicroscopy > Darkfield Illumination Molecular Expressions Darkfield Illumination Primer Gage SH. 1920.
Modern dark-field the history of its development. Transactions of the American Microscopical Society 39:95–141. Dark field and phas
A fluorophore is a fluorescent chemical compound that can re-emit light upon light excitation. Fluorophores contain several combined aromatic groups, or planar or cyclic molecules with several π bonds. Fluorophores are sometimes used alone, as a tracer in fluids, as a dye for staining of certain structures, as a substrate of enzymes, or as a probe or indicator. More they are covalently bonded to a macromolecule, serving as a marker for affine or bioactive reagents. Fluorophores are notably used to stain tissues, cells, or materials in a variety of analytical methods, i.e. fluorescent imaging and spectroscopy. Fluorescein, by its amine reactive isothiocyanate derivative FITC, has been one of the most popular fluorophores. From antibody labeling, the applications have spread to nucleic acids thanks to. Other common fluorophores are derivatives of rhodamine and cyanine. Newer generations of fluorophores, many of which are proprietary perform better, being more photostable, and/or less pH-sensitive than traditional dyes with comparable excitation and emission.
The fluorophore absorbs light energy of a specific wavelength and re-emits light at a longer wavelength. The absorbed wavelengths, energy transfer efficiency, time before emission depend on both the fluorophore structure and its chemical environment, as the molecule in its excited state interacts with surrounding molecules. Wavelengths of maximum absorption and emission are the typical terms used to refer to a given fluorophore, but the whole spectrum may be important to consider; the excitation wavelength spectrum may be a narrow or broader band, or it may be all beyond a cutoff level. The emission spectrum is sharper than the excitation spectrum, it is of a longer wavelength and correspondingly lower energy. Excitation energies range from ultraviolet through the visible spectrum, emission energies may continue from visible light into the near infrared region. Main characteristics of fluorophores are: Maximum excitation and emission wavelength: corresponds to the peak in the excitation and emission spectra, Molar absorption Coefficient: links the quantity of absorbed light, at a given wavelength, to the concentration of fluorophore in solution.
Quantum yield: efficiency of the energy transferred from incident light to emitted fluorescence Lifetime: duration of the excited state of a fluorophore before returning to its ground state. It refers to the time taken for a population of excited fluorophores to decay to 1/e of the original amount. Stokes shift: difference between the maximum excitation and maximum emission wavelengths; these characteristics drive other properties, including photoresistance. Other parameters should be considered, as the polarity of the fluorophore molecule, the fluorophore size and shape, other factors can change the behavior of fluorophores. Fluorophores can be used to quench the fluorescence of other fluorescent dyes or to relay their fluorescence at longer wavelength See more on fluorescence principle. Most fluorophores are organic small molecules of 20 - 100 atoms, but there are much larger natural fluorophores that are proteins: Green fluorescent protein is 27 kDa and several phycobiliproteins are ≈240kDa.
Fluorescence particles are not considered fluorophores. The size of the fluorophore might sterically hinder the tagged molecule, affect the fluorescence polarity. Fluorophore molecules could be either utilized alone, or serve as a fluorescent motif of a functional system. Based on molecular complexity and synthetic methods, fluorophore molecules could be classified into four categories: proteins and peptides, small organic compounds, synthetic oligomers and polymers, multi-component systems. Fluorescent proteins GFP, YFP and RFP can be attached to other specific proteins to form a fusion protein, synthesized in cells after transfection of a suitable plasmid carrier. Non-protein organic fluorophores belong to following major chemical families: Xanthene derivatives: fluorescein, Oregon green and Texas red Cyanine derivatives: cyanine, oxacarbocyanine and merocyanine Squaraine derivatives and ring-substituted squaraines, including Seta, SeTau, Square dyes Naphthalene derivatives Coumarin derivatives oxadiazole derivatives: pyridyloxazole, nitrobenzoxadiazole and benzoxadiazole Anthracene derivatives: anthraquinones, including DRAQ5, DRAQ7 and CyTRAK Orange Pyrene derivatives: cascade blue, etc.
Oxazine derivatives: Nile red, Nile blue, cresyl violet, oxazine 170, etc. Acridine derivatives: proflavin, acridine orange, acridine yellow, etc. Arylmethine derivatives: auramine, crystal violet, malachite green Tetrapyrrole derivatives: porphin, bilirubinThese fluorophores fluoresce due to delocalized electrons which can jump a band and stabilize the energy absorbed. Benzene, one of the simplest aromatic hydrocarbons, for example, is excited at 254 nm
Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light and water waves; the law of reflection says that for specular reflection the angle at which the wave is incident on the surface equals the angle at which it is reflected. Mirrors exhibit specular reflection. In acoustics, reflection is used in sonar. In geology, it is important in the study of seismic waves. Reflection is observed with surface waves in bodies of water. Reflection is observed with many types besides visible light. Reflection of VHF and higher frequencies is important for radar. Hard X-rays and gamma rays can be reflected at shallow angles with special "grazing" mirrors. Reflection of light is either diffuse depending on the nature of the interface. In specular reflection the phase of the reflected waves depends on the choice of the origin of coordinates, but the relative phase between s and p polarizations is fixed by the properties of the media and of the interface between them.
A mirror provides the most common model for specular light reflection, consists of a glass sheet with a metallic coating where the significant reflection occurs. Reflection is enhanced in metals by suppression of wave propagation beyond their skin depths. Reflection occurs at the surface of transparent media, such as water or glass. In the diagram, a light ray PO strikes a vertical mirror at point O, the reflected ray is OQ. By projecting an imaginary line through point O perpendicular to the mirror, known as the normal, we can measure the angle of incidence, θi and the angle of reflection, θr; the law of reflection states that θi = θr, or in other words, the angle of incidence equals the angle of reflection. In fact, reflection of light may occur whenever light travels from a medium of a given refractive index into a medium with a different refractive index. In the most general case, a certain fraction of the light is reflected from the interface, the remainder is refracted. Solving Maxwell's equations for a light ray striking a boundary allows the derivation of the Fresnel equations, which can be used to predict how much of the light is reflected, how much is refracted in a given situation.
This is analogous to the way impedance mismatch in an electric circuit causes reflection of signals. Total internal reflection of light from a denser medium occurs if the angle of incidence is greater than the critical angle. Total internal reflection is used as a means of focusing waves that cannot be reflected by common means. X-ray telescopes are constructed by creating a converging "tunnel" for the waves; as the waves interact at low angle with the surface of this tunnel they are reflected toward the focus point. A conventional reflector would be useless as the X-rays would pass through the intended reflector; when light reflects off a material denser than the external medium, it undergoes a phase inversion. In contrast, a less dense, lower refractive index material will reflect light in phase; this is an important principle in the field of thin-film optics. Specular reflection forms images. Reflection from a flat surface forms a mirror image, which appears to be reversed from left to right because we compare the image we see to what we would see if we were rotated into the position of the image.
Specular reflection at a curved surface forms an image which may be demagnified. Such mirrors may have surfaces that are parabolic. If the reflecting surface is smooth, the reflection of light that occurs is called specular or regular reflection; the laws of reflection are as follows: The incident ray, the reflected ray and the normal to the reflection surface at the point of the incidence lie in the same plane. The angle which the incident ray makes with the normal is equal to the angle which the reflected ray makes to the same normal; the reflected ray and the incident ray are on the opposite sides of the normal. These three laws can all be derived from the Fresnel equations. In classical electrodynamics, light is considered as an electromagnetic wave, described by Maxwell's equations. Light waves incident on a material induce small oscillations of polarisation in the individual atoms, causing each particle to radiate a small secondary wave in all directions, like a dipole antenna. All these waves add up to give specular reflection and refraction, according to the Huygens–Fresnel principle.
In the case of dielectrics such as glass, the electric field of the light acts on the electrons in the material, the moving electrons generate fields and become new radiators. The refracted light in the glass is the combination of the forward radiation of the electrons and the incident light; the reflected light is the combination of the backward radiation of all of the electrons. In metals, electrons with no binding energy are called free electrons; when these electrons oscillate with the incident light, the phase difference between their radiation field and the incident field is π, so the forward radiation cancels the incident light, backward radiation is just the reflected light. Light–matter interaction in terms of photons is a topic of quantum electrodynamics, is described in detail by Richard Feynman in his popular book QED: The Strange Theory of Light and Matter; when light strikes the surface of a mate
For the usage of the phrase "by inspection" in mathematics, see List of mathematical jargon#Proof techniques. An inspection is, most formal evaluation exercise. In engineering activities inspection involves the measurements and gauges applied to certain characteristics in regard to an object or activity; the results are compared to specified requirements and standards for determining whether the item or activity is in line with these targets with a Standard Inspection Procedure in place to ensure consistent checking. Inspections are non-destructive. Inspections may be a visual inspection or involve sensing technologies such as ultrasonic testing, accomplished with a direct physical presence or remotely such as a remote visual inspection, manually or automatically such as an automated optical inspection. Non-contact optical measurement and Photogrammetry have become common NDT methods for inspection of manufactured components and design optimisation. A 2007 Scottish Government review of scrutiny of public services defined inspection of public services as "... periodic, targeted scrutiny of specific services, to check whether they are meeting national and local performance standards and professional requirements, the needs of service users."
A surprise inspection tends to have different results than an announced inspection. Leaders wanting to know how others in their organization perform can drop in without warning, to see directly what happens. If an inspection is made known in advance, it can give people a chance to cover up or to fix mistakes; this could lead to inaccurate findings. A surprise inspection, gives inspectors a better picture of the typical state of the inspected object or process than an announced inspection, it enhances external confidence in the inspection process. See section 4.12 of the Crear report. Quality related in-process inspection/verification is an essential part of quality control in manufacturing. Inspection in manufacturing includes measuring, testing, or gauging one or more characteristics of a product or process and comparing the results with specified requirements to determine whether is the requirements are met for each characteristic. Common examples of inspection by measurement or gauging include using a caliper or micrometer to determine if a dimension of a manufactured part is within the dimensional tolerance specified in a drawing for that part, is thus acceptable for use.
Design for Inspection is a concept that should complement and work in collaboration with Design for Manufacturability and Design for Assembly to reduce product manufacturing cost and increase manufacturing practicality. Photogrammetry is a modern way of visual inspection, delivering high accuracy and traceability for various industries; the portable 3D system is a versatile optical coordinate measuring machine with a wide range of capabilities. Accurate point measurements can be taken with inspection carried out directly to CAD models, geometry or drawings. Most fire equipment needs to be inspected to make sure in the event of a fire, every effort has been taken to make sure it doesn't get out of control. Extinguishers are to be inspected every month by law and inspected by a servicing company at least once a year. Fire extinguishers can be heavy, so it's a good idea to practice picking up and holding an extinguisher to get an idea of the weight and feel. In international trade several destination countries require pre-shipment inspection.
The importer instructs the shipper. The inspector makes pictures and a report to certify that the goods that are being shipped and produced are in accordance with the accompanying documents. Commodity inspection is other term, used between buyers and sellers; the scope of work for commodity inspection depends to the buyers. Some buyers hire the inspection agencies only for pre-shipment inspections i.e. visual quality, packing and loading inspections and some others request for higher level inspections and ask inspection agencies to attend in the vendor shops and inspect commodities during manufacturing processes. Inspection is done based on an agreed inspection and test plan. In government and politics, an inspection is the act of a monitoring authority administering an official review of various criteria that are deemed by the authority to be related to the inspection. Inspections are used for the purpose of determining; the inspector examines the talks with involved individuals. A report and evaluation follows such visits.
The Food Safety Inspection Service is charged with ensuring that all meat and egg products in the United States are safe to consume and labeled. The Meat Inspection Act of 1906 authorized the Secretary of Agriculture to order meat inspections and condemn any found unfit for human consumption; the United Nations Monitoring and Inspection Commission is a regulatory body that inspects for weapons of mass destruction. The Scottish Commission for the Regulation of Care inspects care services in Scotland. A vehicle inspection, e.g. an annual inspection, is a necessary inspection required on vehicles to conform with laws regarding safety, emissions, or both. It consists of an examination of a vehicle's components done by a certified mechanic. Vehicles pass a pre-warranty inspection, if, only if, a mechanic provide evidence for the proper working condition of the vehicle systems specified in the type of inspection. A mechanical inspection is undertaken to ensure the safety or reliability o