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Deinterlacing is the process of converting interlaced video, such as common analog television signals or 1080i format HDTV signals, into a non-interlaced form. Interlaced video frame consists of two sub-fields taken in sequence, each sequentially scanned at odd then even lines of the image sensor; analog television employed this technique because it allowed for less transmission bandwidth and further eliminated the perceived flicker that a similar frame rate would give using progressive scan. CRT based displays were able to display interlaced video correctly due to its complete analogue nature. All of the newer displays are inherently digital in that the display comprises discrete pixels. Consequently the two fields need to be combined into a single frame, which leads to various visual defects which the deinterlacing process should try to minimise. Deinterlacing has been researched for decades and employs complex processing algorithms; however, consistent results have been very hard to achieve.〔 〕〔 == Background == Both video and photographic film capture a series of frames (still images) in rapid succession; however, television systems read the captured image by serially scanning the image sensor by lines (rows). In analog television, each frame is divided into two consecutive fields, one containing all even lines, another with the odd lines. The fields are captured in succession at a rate twice that of the nominal frame rate. For instance, PAL and SECAM systems have a rate of 25 frames/s or 50 fields/s, while the NTSC system delivers 29.97 frames/s or 59.94 fields/s. This process of dividing frames into half-resolution fields at double the frame rate is known as ''interlacing''. Since the interlaced signal contains the two fields of a video frame shot at two different times, it enhances motion perception to the viewer and reduces flicker by taking advantage of the persistence of vision effect. This results in an effective doubling of time resolution as compared with non-interlaced footage (for frame rates equal to field rates). However, interlaced signal requires a display that is natively capable to show the individual fields in a sequential order, and only traditional CRT-based TV sets are capable of displaying interlaced signal, due to the electronic scanning and lack of apparent fixed resolution. Most modern displays, such as LCD, DLP and plasma displays, are not able to work in interlaced mode, because they are fixed-resolution displays and only support progressive scanning. In order to display interlaced signal on such displays, the two interlaced fields must be converted to one progressive frame with a process known as ''de-interlacing''. However, when the two fields taken at different points in time are re-combined to a full frame displayed at once, visual defects called ''interlace artifacts'' or ''combing'' occur with moving objects in the image. A good deinterlacing algorithm should try to avoid interlacing artifacts as much as possible and not sacrifice image quality in the process, which is hard to achieve consistently. There are several techniques available that extrapolate the missing picture information, however they rather fall into the category of intelligent frame creation and require complex algorithms and substantial processing power. Deinterlacing techniques require complex processing and thus can introduce a delay into the video feed. While not generally noticeable, this can result in the display of older video games lagging behind controller input. Many TVs thus have a "game mode" in which minimal processing is done in order to maximize speed at the expense of image quality. Deinterlacing is only partly responsible for such lag; scaling also involves complex algorithms that take milliseconds to run. 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「Deinterlacing」の詳細全文を読む スポンサード リンク
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