EMC 3130 Spring 2012 Lecture One Image Digital
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EMC 3130 Spring 2012 Lecture One Image Digital

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EMC 3130 Spring 2012 Lecture One Image Digital EMC 3130 Spring 2012 Lecture One Image Digital Presentation Transcript

  • EMC 3130 Lecture OneDigital Video – How Does This Work? Pixels to Scenes Edward Bowen
  • How Television Workshttp://www.youtube.com/watch?v=UivqdpliyA0
  • How Digital Cameras Workhttp://www.youtube.com/watch?v=VP__-EKrkbk
  • Digital Camera Deconstructedhttp://videos.howstuffworks.com/science-channel/37727-deconstructed-digital-cameras-video.htm
  • What is Video?Video is electronically captured and disseminated sequential still images (frames) in rapid enough succession to create the illusion of motion, stored either analog or digitally, and synchronized with sound.
  • What is Video?Video is electronically captured and disseminated sequential still images (frames) in rapid enough succession to create the illusion of motion, stored either analog or digitally, and synchronized with sound.
  • Analog• A wave is recorded or used in its original form• Light or sound are converted to a fluctuating electrical wave that is directly recorded, usually to a magnetic tape medium, mirroring the original stimulus.• It produces an electrical copy of an original stimulus.• Analog signal fluctuates exactly like the original stimulus.• Analog signal is continuous.
  • Digital• The analog wave is sampled at some interval, and then turned into numbers that are stored in the digital device• Light and sound are recorded not as an identical copy of the original stimulus, but as discrete on-and-off pulses, zeros and ones, binary digits.• It is a representation rather than a copy.• Discontinuous. Signal is sampled.• Advantage: Resists data distortion and error in duplication. No generational loss.• Advantage: Allows for manipulation of sound and image.
  • Digitalhttp://youtu.be/kR7227_ndqQ
  • Digitalhttp://www.dailymotion.com/video/xkgkkv_dr-michio-kaku-on-the-conversion-from-analog-to-digital_tech
  • Digital
  • Digital• Sampling/Quantizing• Compression and Codecs (Compression- Decompression, Encoding-Decoding)• Downloading and StreamingAdvantages• Lossless Copying• Compression• Manipulation
  • Basic Image FormationCompression• CODEC – a device or program for encoding and/or decoding digital information (DivX, Xvid, H.264, WMV, etc.)• Container of Wrapper Format (AVI, FLV, QuickTIme, MPEG, MP4, etc.)• Lossy vs. Lossless• Lossy - Permanently removes information, such as repeated pixels.• Lossless - Compresses and decompressed without loss of information.• Compression Ratio - the higher the ratio, the smaller the file; the lower the ratio, the higher the quality.
  • Digital Compressionhttp://vimeo.com/1172256
  • Digital Compressionhttp://youtu.be/nH3nmBEPIHY
  • What is Video?Video is electronically captured and disseminated sequential still images (frames) in rapid enough succession to create the illusion of motion, stored either analog or digitally, and synchronized with sound.
  • Sequential Still Images (Frames)• The individual pictures that make up video are “frames.”
  • Sequential Still Images (Frames)• The individual pictures that make up video are “frames.”• The frames are comprised of millions of electrically excitable “pixels” (picture elements)
  • Pixels• The individual pictures that make up video are “frames.”• The frames are comprised of millions of electrically excitable “pixels” (picture elements)• For color, each pixel is comprised of three parts (red, blue, green)
  • Pixelshttp://youtu.be/ugV6cLgwomo
  • Pixelshttp://youtu.be/DCTRk5a0aJg
  • Pixelshttp://vimeo.com/18881890
  • Sequential Still Images (Frames)• The individual pictures that make up video are “frames.”• The frames are comprised of millions of electrically excitable “pixels” (picture elements)• For color, each pixel is comprised of three dots (red, blue, green)• Individual images are drawn by scanning along these pixels from left to right, top to bottom.
  • Scanning High speed video showing the fluorescent screen of CRT television being scanned by electron gun.http://youtu.be/zVS6QewZsi4
  • Scanninghttp://www.dailymotion.com/video/xjoyzr_cbs-entertainment-productions-london-films-persistence-of-vision-mgm-television_shortfilms
  • Scanning• Interlaced Scanning - Two fields comprise a frame.
  • Scanning• Interlaced Scanning Misaligned fields
  • Scanning• Progressive Scanning (Computers and Most Digital Video)• Refresh Rate: Frames scanned per second.
  • Scanning• Progressive v Interlaced Scanning
  • Scanning• Progressive v Interlaced Scanning
  • Scanning • Progressive v Interlaced Scanninghttp://youtu.be/gbtBP8QxGg8
  • Scanninghttp://video.answers.com/how-ntsc-interlaced-video-works-291907666
  • ResolutionStandard Television• 480i (480 horizontal lines visible, interlaced; 30 frames per second)
  • ResolutionDigital Television (DTV)• Higher Picture Resolution• Truer Color• Wider Contrast RatioFour prominent systems:• 480p (progressive, 480 visible lines, 60 frames per second)• 720p (progressive, 720 visible lines, 60 frames per second, High Definition Television [HDTV]• 1080i (interlaced, 60 fields/30 frames per second, High Definition Television [HDTV]• 1080p (progressive, 60 frames per second, [HDTV]
  • Resolution
  • Resolution720p 1080p
  • Resolution
  • ResolutionAdditional Systems24p - 1080 lines of resolution, 24 frames per second.• For use in conjunction with motion picture film• Or to create a “film look.”
  • Resolutionhttp://vimeo.com/3388256
  • ResolutionAdditional Systems2K, 4K and 5K – 2000, 4000 and 5000 lines ofresolution• For use in theatrical screening and 35mm scanning
  • ResolutionResolution – The Detail an Image Contains• Horizontal lines of pixels times vertical lines of pixels• VHS - 200 by 480• Mini-DV - 720 by 480• CineAlta 24p - 1920 by 1080• 35mm film - 4000 by 3000• Red One - 4520 by 2540
  • ResolutionResolution – The Detail an Image Contains• Horizontal lines of pixels times vertical lines of pixelsAnalog and early digital• 300×480 : VHS,• 500×480 : Analog broadcast
  • ResolutionResolution – The Detail an Image Contains• Horizontal lines of pixels times vertical lines of pixelsDigital• 720×480 :DVD, miniDV• 1280×720 (-1MP) : HD DVD, Blu-ray, HDV (miniDV)• 1440×1080 (1.5 MP) : HDV (miniDV)• 1920×1080 (2MP) : HDV (miniDV), AVCHD, HD DVD, Blu-ray,• 2048×1080 : 2K Digital Cinema• 4096×2160 : 4K Digital Cinema• Sequences from newer films are scanned at 2,000, 4,000, or even 8,000 columns, called 2K, 4K, and 8K, for quality visual- effects editing on computers
  • What is Video?Video is electronically captured and disseminated sequential still images (frames) in rapid enough succession to create the illusion of motion, stored either analog or digitally, and synchronized with sound.
  • Frame Rates(frames per second) Shutter Speed(fraction of a second)
  • Frame RatesThe number of frames captured in a second (frames per second) Shutter Speed -The time light is allowed to strike the image sensor to create a single image. (fraction of a second)
  • Frame Rates (frames per second)Higher frame capture and playback rates result in more information and higher picture quality with increasedsharpness, less stutter and flicker, and less motion blur.
  • Frame Rates (frames per second) Impact on Image Quality and Smoothness of Motionhttp://youtu.be/e54Q1KXRmX0
  • Frame Rates (frames per second) Impact on Image Quality and Smoothness of Motionhttp://youtu.be/-nU2_ERC_oE
  • Frame Rates (frames per second) Impact on Image Quality and Smoothness of Motionhttp://youtu.be/3xsSSsVqSA0
  • Frame Rates (frames per second) Impact on Video SpeedWhen video is played back at the same frame rate as it was captured, motion appears normal. When video capture speed is faster than it is played back, slow motion results, since the video is playing back at a SLOWER speed than it was captured. 30fps Capture - 30fps Playback: Normal Motion 60fps Capture - 60fps Playback: Normal Motion 60fps Capture - 30fps Playback: Slow Motion 300fps Capture - 30fps Playback: Slow Motion
  • Frame Rates (frames per second) Impact on Video SpeedWhen video is played back at the same frame rate as it was captured, motion appears normal. When video capture speed is slower than it is playedback, fast motion results, since the video is playing back at a FASTER speed than it was captured. 30fps Capture - 30fps Playback: Normal Motion 60fps Capture - 60fps Playback: Normal Motion 30fps Capture - 60fps Playback: Fast Motion 3fps Capture - 30fps Playback: Fast Motion
  • Frame Rates (frames per second) Impact on Video SpeedWhen video is played back at the same frame rate as it was captured, motion appears normal. When video playback speed is altered in post production to a slower frame rate than it wascaptured, slow motion results, since the video is playing back at a SLOWER speed than it was captured. 30fps Capture - 30fps Playback: Normal Motion 60fps Capture - 60fps Playback: Normal Motion60fps Capture -30fps (or 50%) Playback: Slow Motion 60fps Capture - 6fps (10%) Playback: Slow Motion
  • Frame Rates (frames per second) Impact on Video Speed When video is played back at the same frame rate as it was captured, motion appears normal.When video playback speed is altered in post production to a fasterframe rate than it was captured, fast motion results, since the video is playing back at a FASTER speed than it was captured. 30fps Capture - 30fps Playback: Normal Motion 60fps Capture -60fps Playback: Normal Motion 60fps Capture -120fps (or 200%) Playback: Fast Motion 60fps Capture - 600fps (1000%) Playback: FAST Motion
  • Frame Rates (frames per second) Impact on Image Speedhttp://vimeo.com/11648907
  • Frame Rates (frames per second) Impact on Image Speedhttp://youtu.be/kgdyBvHdNKY
  • Shutter Speed (fraction of a second) Generally, shutter speed must be at least half of theframe rate. At 30 frames per second, the shutter speed will be approximately 1/60th of a second. It can be faster is the camera allows. A higher frame rate requires a faster shutter speed. Shutter speed can be increased independent of the frame rate. A faster the shutter speed results in diminished blur A slower shutter speed results in added blur.
  • Shutter Speed (fraction of a second)Impact on Motion Blur
  • Shutter Speed (fraction of a second)Impact on Motion Blur
  • Shutter Speed (fraction of a second)Impact on Motion Blur
  • Shutter Speed (fraction of a second)Impact on Motion Blur
  • Shutter Speed (fraction of a second)Impact on Motion Blur
  • Shutter Speed (fraction of a second) Impact on Motion Blurhttp://vimeo.com/18873243
  • Shutter Speed (fraction of a second) Impact on Motion Blurhttp://youtu.be/gFjbVZJ275k
  • Shutter Speed (fraction of a second) Impact on Motion Blurhttp://vimeo.com/20310729
  • What is Video?Video is electronically captured and disseminated sequential still images (frames) in rapid enough succession to create the illusion of motion, stored either analog or digitally, and synchronized with sound.
  • The Illusion of Motion • Persistence of Vision, Beta Movement, Phi Phenomenonhttp://www.youtube.com/watch?v=3veFqnnob0A
  • The Illusion of Motion• Persistence of Vision, Beta Movement, Phi Phenomenon
  • The Illusion of Motion• Flicker Fusion and Frequency - the flickering of light rapidly enough to merge or fuse the images• Apparent motion - Creating the illusion of motion
  • Basic Image Formation• Scanning• Fields / Frames• Flicker Frequency: Flashes per second• Apparent motion• Frames per secondhttp://dsc.discovery.com/videos/assignment-discovery- shorts-tv-tube-and-the-flicker-frequency.html
  • Realityhttp://youtu.be/6jzNw4_2YGQ
  • Basic Image FormationRecording Media• Film Stock• Analog Video Cassette tape• Digital Video Cassette tape• DVD discs• Digital Hard Drives• Digital Memory Cards
  • NTSC National Television System Committee• http://www.ehow.com/video_4751914_ what-ntsc-video.html• http://www.ehow.com/video_4751915_ what-difference-between-ntsc-pal.html
  • NTSCNational Television System Committee
  • NTSCNational Television System Committee