Digital ICE

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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.

Fast Fourier transform O(n logn) divide and conquer algorithm to calculate the discrete Fourier transforms

A fast Fourier transform (FFT) is an algorithm that computes the discrete Fourier transform (DFT) of a sequence, or its inverse (IDFT). Fourier analysis converts a signal from its original domain to a representation in the frequency domain and vice versa. The DFT is obtained by decomposing a sequence of values into components of different frequencies. This operation is useful in many fields, but computing it directly from the definition is often too slow to be practical. An FFT rapidly computes such transformations by factorizing the DFT matrix into a product of sparse factors. As a result, it manages to reduce the complexity of computing the DFT from , which arises if one simply applies the definition of DFT, to , where is the data size. The difference in speed can be enormous, especially for long data sets where N may be in the thousands or millions. In the presence of round-off error, many FFT algorithms are much more accurate than evaluating the DFT definition directly. There are many different FFT algorithms based on a wide range of published theories, from simple complex-number arithmetic to group theory and number theory.

Contents

The term Digital ICE initially applied specifically to a proprietary technology developed by Kodak's Austin Development Center, formerly Applied Science Fiction (ASF), that automatically removes surface defects, such as dust and scratches, from scanned images.

Dust small particles in the air

Dust are fine particles of solid matter. It generally consists of particles in the atmosphere that come from various sources such as soil, dust lifted by wind, volcanic eruptions, and pollution. Dust in homes, offices, and other human environments contains small amounts of plant pollen, human and animal hairs, textile fibers, paper fibers, minerals from outdoor soil, human skin cells, burnt meteorite particles, and many other materials which may be found in the local environment.

Image scanner device that optically scans images, printed text, handwriting, or an object, and converts it to a digital image

An image scanner—often abbreviated to just scanner, although the term is ambiguous out of context —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.

Technology

The ICE technology works from within the scanner, so unlike the software-only solutions it does not alter any underlying details of the image. Subsequent to the original Digital ICE technology, which used infrared cleaning, additional image enhancement technologies were marketed by Applied Science Fiction and Kodak under similar and related names, often as part of a suite of compatible technologies. The ICE technology uses a scanner with a pair of light sources, a normal RGB lamp and an infrared (IR) lamp, and scans twice, once with each lamp. The IR lamp detects the dust locations with its unique detection method, and then inpainting is applied based on this data afterwards. The general concept is to subtract the position of scratches and dust from the RGB image.

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. 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.

Inpainting

Inpainting is the process of reconstructing lost or deteriorated parts of images and videos. In the museum world, in the case of a valuable painting, this task would be carried out by a skilled art conservator or art restorer. In the digital world, inpainting refers to the application of sophisticated algorithms to replace lost or corrupted parts of the image data.

Limitations of Digital ICE

Digital ICE is used to detect scratches and dust during transparent film scan and is not applicable for opaque document scanning. While chromogenic black-and-white films are supported by Digital ICE, other black-and-white films containing metallic silver, which form from silver halides during the development process of the film, are not. This is because the long wave infrared light passes through the slide but not through dust particles. The silver particles reflect the infrared light in a similar manner to dust particles, thus respond equally in visible light and infrared. A similar phenomenon also prevents Kodak Kodachrome slides from being scanned with Digital ICE. Kodachrome's cyan layer absorbs infrared.

Metal element, compound, or alloy that is a good conductor of both electricity and heat

A metal is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically malleable or ductile. A metal may be a chemical element such as iron, or an alloy such as stainless steel.

Silver Chemical element with atomic number 47

Silver is a chemical element with symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. The metal is found in the Earth's crust in the pure, free elemental form, as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc refining.

A silver halide is one of the chemical compounds that can form between the element silver and one of the halogens. In particular, bromine, chlorine, iodine and fluorine may each combine with silver to produce silver bromide (AgBr), silver chloride (AgCl), silver iodide (AgI), and three forms of silver fluoride, respectively.

Further development

Kodak's own scanner, the "pro-lab" Kodak HR500 Plus was equipped with Digital ICE that could scan Kodachrome slides effectively; however, this scanner was discontinued in 2005. Nikon produced the Nikon Super Coolscan LS-9000 ED scanner with a new version of ICE (Digital ICE Professional) from 2004 until it was discontinued in 2010. This was capable of scanning Kodachrome slides reliably, dust- and scratch-free, without additional software. LaserSoft Imaging released an infrared dust and scratch removal tool (iSRD - Infrared Smart Removal of Defects) in 2008, that allows Nikon's film scanners for Mac OS X and Microsoft Windows, as well as many scanners from other manufacturers to make high quality scans of Kodachrome slides. Fujifilms system for dust and scratch removal, called "Image Intelligence", works on a similar principle as Digital ICE and will also work on Kodachrome film.

Nikon Japanese multinational corporation headquartered in Tokyo, Japan, specializing in optics and imaging

Nikon Corporation, also known just as Nikon, is a Japanese multinational corporation headquartered in Tokyo, Japan, specializing in optics and imaging products.

LaserSoft Imaging German computer software company

LaserSoft Imaging AG is a software developer designing software such as SilverFast for scanners and digital cameras. The company's headquarters are located in Kiel, Germany, 100 kilometres (62 mi) north of Hamburg, and another office in Sarasota, Florida, United States.

Microsoft Windows is a group of several graphical operating system families, all of which are developed, marketed, and sold by Microsoft. Each family caters to a certain sector of the computing industry. Active Windows families include Windows NT and Windows Embedded; these may encompass subfamilies, e.g. Windows Embedded Compact or Windows Server. Defunct Windows families include Windows 9x, Windows Mobile and Windows Phone.

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Kodachrome A brand name for a non-substantive, color reversal film introduced by Eastman Kodak in 1935.

Kodachrome is a brand name for a non-substantive, 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. Because of its complex processing requirements, the film was sold process-paid in the United States until 1954 when a legal ruling prohibited this. Elsewhere, this arrangement continued.

Photographic processing or development is the chemical means by which photographic film or paper is treated after photographic exposure to produce a negative or positive image. Photographic processing transforms the latent image into a visible image, makes this permanent and renders it insensitive to light.

Reversal film type of photographic film that produces a positive image on a transparent base

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Infrared photography

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Photographic film sheet of plastic coated with light-sensitive chemicals

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Spirit DataCine

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