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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. ==Method== 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. On the other hand, dust and scratches absorb in the infrared. 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〔(CreativePro - Bit by Bit: New Scanner Gives Life to Old Film ) by Brian P. Lawler (Photographer)〕), VueScan's〔http://www.hamrick.com/vuescan/vuescan.htm〕 and SilverFast's,〔http://www.silverfast.com/highlights/isrd/en.html〕 claim to use infrared cleaning to find dust spots even when scanning Kodachrome. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Infrared cleaning」の詳細全文を読む スポンサード リンク
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