مسح متداخل

المسح المتداخل Interlace هو أحد أساليب المسح الرئيسية التي تستخدم في البث التلفزيوني الاعتيادي وضمن أسلوب البث التلفزيوني المتطور 1080i. يعتبر هذا الأسـلوب معاكســا لأسـلوب المسح المتطور Progressive Scanning في طريقة مسـحه للصور ذلك أن أسـلوب المسح المتطور Progressive Scanning يقوم بمسح الصورة أو إضفاء الألوان عليها جملة واحدة. في حين أن الأسلوب المتداخل (أو المتشابك) يقوم بمسح السطور ذات الأرقام الفردية تسلسليا ثم يعود ويقوم بمسـح السطور المتبقية أي ذات الأرقام الزوجية. يعتبر أسـلوب المسح هذا وفق رأي بعض الفنيين بأنه أقرب إلى تشويش الصورة وأقل استقرارا من المسح المتطور.

هذا التحريك يوضح تأثيرthe interline twitter . On the left are two progressive scan images. Center are two interlaced images. Right are two images with line doublers. Top are original resolution, bottom are with anti-aliasing. The two interlaced images use half the bandwidth of the progressive one. The interlaced scan (right) precisely duplicates the pixels of the progressive image (left), but interlace causes details to twitter. A line doubler operating in "bob" (interpolation) mode would produce the images at far right. Real interlaced video blurs such details to prevent twitter, as seen in the bottom row, but such softening (or anti-aliasing) comes at the cost of resolution. But even the best line doubler could never restore the bottom center image to the full resolution of the progressive image. Note – Because the frame rate has been slowed down by a factor of 3, you will notice additional flicker in simulated interlaced portions of this image.

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 انظر أيضاً

• 480i: standard-definition interlaced video usually used in traditionally NTSC countries (North and parts of South America, Japan)
• 576i: standard-definition interlaced video usually used in traditionally PAL and SECAM countries
• 1080i: high-definition television (HDTV) digitally broadcast in 16:9 (widescreen) aspect ratio standard
• Progressive scan: the opposite of interlacing; the image is displayed line by line.
• Deinterlacing: converting an interlaced video signal into a non-interlaced one
• Telecine: a method for converting film frame rates to television frame rates using interlacing
• Federal Standard 1037C: defines Interlaced scanning
• Interleaving
• Moving image formats
• Wobulation: a variation of interlacing used in DLP displays

 المصادر

• فكرة عمل التلفزيون

 وصلات خارجية

• Fields: Why Video Is Crucially Different from Graphics – An article that describes field-based, interlaced, digitized video and its relation to frame-based computer graphics with lots of illustrations
• Digital Video and Field Order - An article that explains with diagrams how the field order of PAL and NTSC has arisen, and how PAL and NTSC is digitized
• 100FPS.COM* – Video Interlacing/Deinterlacing
• Stream Interlace and Deinterlace (planetmath.org)
• Interlace / Progressive Scanning - Computer vs. Video
• Sampling theory and synthesis of interlaced video
• Interlaced versus progressive
• More about Interlaced versus progressive