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Infrared cleaning is a technique used by some film scanners and flatbed scanners to reduce or remove the effect of dust and scratches upon the finished scan. It works by collecting an additional infrared channel from the scan at the same position and resolution as the three visible color channels (red, green, and blue). The infrared channel, in combination with the other channels, is used to detect the location of scratches and dust. Once located, those defects can be corrected by scaling or replaced by inpainting.
The three color dyes in typical color film emulsions are largely transparent to infrared light, so the infrared image is almost uniformly clear, unlike the RGB images. [1] On the other hand, dust absorbs and scratches scatter the infrared. [2] Any dust spots or scratches appear as dark marks in the infrared, making them easy to find and compensate for.
Pixels that are partially occluded (for example, the dust only obscures a small portion of the pixel) may be corrected by scaling. The infrared pixel value indicates the fractional amount of the occlusion, and RGB values can be scaled appropriately.
If most or all of a pixel is occluded, scaling is not feasible. Instead, the pixel value may be interpolated from nearby good pixels (inpainting).
Infrared cleaning is not possible with media which are not transparent to infrared. In particular the silver particles in silver halide black-and-white film respond equally to visible and infrared light, with no difference between dark pixels and dust, and infrared cleaning is not possible. Infrared cleaning does work with chromogenic black-and-white films, which do not contain silver particles.
Some film dyes also block infrared to a considerable extent; infrared cleaning works with Ektachrome slide film, but it is more difficult to find dust spots with the infrared-blocking dyes used in Kodachrome. Some software algorithms, such as the latest ICE implementation (Nikon Super Coolscan LS-9000 ED with Digital ICE Professional [3] ), VueScan's [4] and SilverFast's, [5] claim to use infrared cleaning to find dust spots even when scanning Kodachrome.
Scanners use three different techniques for doing this:
IBM originally developed and patented infrared cleaning, and subsequently licensed this patent to Applied Science Fiction (ASF). Canon had a patent cross-licensing agreement with IBM, and thus was able to use IBM's infrared cleaning patent. Canon could not use the trademarked Digital ICE name, so instead called it Film Automatic Retouching and Enhancement (FARE). Other companies, including Hamrick Software and LaserSoft Imaging, independently developed infrared cleaning algorithms which are completely different from IBM's patented algorithm.
ASF subsequently went out of business, having spent all their money trying to develop dry film development in a kiosk at a time when digital photography was replacing film. Kodak purchased the assets of ASF, but did not use any of its technologies.
The RGB color model is an additive color model in which the red, green and blue primary colors of light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three additive primary colors, red, green, and blue.
A digital camera is a camera that captures photographs in digital memory. Most cameras produced today are digital, largely replacing those that capture images on photographic film. Digital cameras are now widely incorporated into mobile devices like smartphones with the same or more capabilities and features of dedicated cameras. High-end, high-definition dedicated cameras are still commonly used by professionals and those who desire to take higher-quality photographs.
The following list comprises significant milestones in the development of photography technology.
Kodachrome is the brand name for a color reversal film introduced by Eastman Kodak in 1935. It was one of the first successful color materials and was used for both cinematography and still photography. For many years, Kodachrome was widely used for professional color photography, especially for images intended for publication in print media.
An image scanner—often abbreviated to just scanner—is a device that optically scans images, printed text, handwriting or an object and converts it to a digital image. Commonly used in offices are variations of the desktop flatbed scanner where the document is placed on a glass window for scanning. Hand-held scanners, where the device is moved by hand, have evolved from text scanning "wands" to 3D scanners used for industrial design, reverse engineering, test and measurement, orthotics, gaming and other applications. Mechanically driven scanners that move the document are typically used for large-format documents, where a flatbed design would be impractical.
In photography, reversal film or slide film is a type of photographic film that produces a positive image on a transparent base. Instead of negatives and prints, reversal film is processed to produce transparencies or diapositives. Reversal film is produced in various sizes, from 35 mm to roll film to 8×10 inch sheet film.
A Bayer filter mosaic is a color filter array (CFA) for arranging RGB color filters on a square grid of photosensors. Its particular arrangement of color filters is used in most single-chip digital image sensors used in digital cameras, camcorders, and scanners to create a color image. The filter pattern is half green, one quarter red and one quarter blue, hence is also called BGGR,RGBG, GRBG, or RGGB.
The Cineon System was one of the first computer based digital film systems, created by Kodak in the early 1990s. It was an integrated suite of components consisting a Motion picture film scanner, a film recorder and workstation hardware with software for compositing, visual effects, image restoration and color management.
A film scanner is a device made for scanning photographic film directly into a computer without the use of any intermediate printmaking. It provides several benefits over using a flatbed scanner to scan in a print of any size: the photographer has direct control over cropping and aspect ratio from the original, unmolested image on film; and many film scanners have special software or hardware that removes scratches and film grain and improves color reproduction from film.
Photo CD is a system designed by Kodak for digitizing and saving photos onto a CD. Launched in 1991, the discs were designed to hold nearly 100 high quality images, scanned prints and slides using special proprietary encoding. Photo CDs are defined in the Beige Book and conform to the CD-ROM XA and CD-i Bridge specifications as well. They were intended to play on CD-i players, Photo CD players, and any computer with a suitable software.
The Nikon D1 is a digital single-lens reflex camera (DSLR) that was made by Nikon Corporation introduced on June 15, 1999. It features a 2.7-megapixel image sensor, 4.5-frames-per-second continuous shooting, and accepts the full range of Nikon F-mount lenses. The camera body strongly resembles the F5 and has the same general layout of controls, allowing users of Nikon film SLR cameras to quickly become proficient in using the camera. Autofocus speed on the D1 series bodies is extremely fast, even with "screw-driven" AF lenses.
A camera raw image file contains unprocessed or minimally processed data from the image sensor of either a digital camera, a motion picture film scanner, or other image scanner. Raw files are so named because they are not yet processed, and contain large amounts of potentially redundant data. Normally, the image is processed by a raw converter, in a wide-gamut internal color space where precise adjustments can be made before conversion to a viewable file format such as JPEG or PNG for storage, printing, or further manipulation. There are dozens of raw formats in use by different manufacturers of digital image capture equipment.
A motion picture film scanner is a device used in digital filmmaking to scan original film for storage as high-resolution digital intermediate files.
Digital ICE or Digital Image Correction and Enhancement is a set of technologies related to producing an altered image in a variety of frequency spectra. The objective of these technologies is to render an image more usable by Fourier or other filtering techniques. These technologies were most actively advanced in the 1960s and early 1970s in the fields of strategic reconnaissance and medical electronics.
Digital photography uses cameras containing arrays of electronic photodetectors interfaced to an analog-to-digital converter (ADC) to produce images focused by a lens, as opposed to an exposure on photographic film. The digitized image is stored as a computer file ready for further digital processing, viewing, electronic publishing, or digital printing. It is a form of digital imaging based on gathering visible light.
The following outline is provided as an overview of and topical guide to photography:
Scanography, more commonly referred to as scanner photography, is the process of capturing digitized images of objects for the purpose of creating printable art using a flatbed "photo" scanner with a CCD array capturing device. Fine art scanography differs from traditional document scanning by using atypical objects, often three-dimensional, as well as from photography, due to the nature of the scanner's operation.
SilverFast is the name of a family of software for image scanning and processing, including photos, documents and slides, developed by LaserSoft Imaging.
Photographic film is a strip or sheet of transparent film base coated on one side with a gelatin emulsion containing microscopically small light-sensitive silver halide crystals. The sizes and other characteristics of the crystals determine the sensitivity, contrast, and resolution of the film.
Spirit DataCine is a telecine and a motion picture film scanner. This device is able to transfer 16mm and 35mm motion picture film to NTSC or PAL television standards or one of many High-definition television standards. With the data transfer option a Spirit DataCine can output DPX data files. The image pick up device is a solid state charge-coupled device. This eliminated the need for glass vacuum tube CRTs used on older telecines. The units can transfer negative film, primetime, intermediate film and print film, stock. One option is a Super 8 gate for the transfer of Super 8 mm film. With a sound pick up option, optical 16mm and 35mm sound can be reproduced, also 16mm magnetic strip sound. The unit can operate stand alone or be controlled by a scene by scene color corrector. Ken Burns created The Civil War, a short documentary film included in the DVD release, on how he used the Spirit DataCine to transfer and remaster this film. The operator of the unit is called a Colorist or Colorist Assistant. The Spirit DataCine has become the standard for high-end real-time film transfer and scanning. Over 370 units are used in post-production facilities around the world. Most current film productions are transferred on Spirit DataCines for Television, Digital television, Cable television, Satellite television, Direct-to-video, DVD, Blu-ray Disc, pay-per-view, In-flight entertainment, Stock footage, Dailies, Film preservation, digital intermediate and digital cinema. The Spirit DataCine is made by DFT Digital Film Technology GmbH in Darmstadt, Germany.