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pixel_binning [2021/02/03 09:54]
Audionut fix photosites
pixel_binning [2021/02/03 12:10]
Audionut minor
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-What happens is that every single Bayer pixel processed by the camera might be obtained by averaging data from a few photosites (smallest units of the imaging sensor). This averaging process happens in the analog domain. When pixel binning is used, the image received/processed by the camera software is already pixel-binned (the image sensor is not read out at its full resolution).+**This is a more detailed description of [[/glossary/#Pixel Binning]], including specific examples from Canon cameras.** 
 + 
 +When the cameras software does not process every single [[/glossary/#photosite]], what happens is that every single [[/glossary/#Bayer]] photosite processed by the camera might be obtained by averaging data from a few photosites. This averaging process happens in the [[/glossary/#analogdomain. When pixel binning is used, the image received/processed by the camera software is already pixel-binned (the image sensor is not read out at its full resolution).
  
 Advantages: Advantages:
   * relatively simple to implement with analog electronics;   * relatively simple to implement with analog electronics;
-  * all sensor photosites contribute to the final image (nothing is lost), unless [[#Line Skipping]] is used;+  * all sensor photosites contribute to the final image (nothing is lost), unless [[/glossary/#Line Skipping]] is used;
   * lower data rate to process for a single LiveView or video frame;   * lower data rate to process for a single LiveView or video frame;
   * easier to achieve a high frame rate without requiring huge processing power (compared to a complete readout at full resolution, followed by a resizing step in digital domain);   * easier to achieve a high frame rate without requiring huge processing power (compared to a complete readout at full resolution, followed by a resizing step in digital domain);
-  * reasonably good performance on high-frequency details (very few aliasing/moire issues on a [[#Resolution Chart]]).+  * reasonably good performance on high-frequency details (very few aliasing/moire issues on a [[/glossary/#Resolution Chart]]).
  
 Disadvantages: Disadvantages:
   * less image detail (compared to a full resolution image resized to match video resolution);   * less image detail (compared to a full resolution image resized to match video resolution);
   * some noise introduced by analog electronics (compared to averaging the same pixels in software, from a full resolution image);   * some noise introduced by analog electronics (compared to averaging the same pixels in software, from a full resolution image);
-  * available binning factors are [[#hardwired]].+  * available binning factors are [[/glossary/#hardwired]].
  
-Most Canon cameras use [[#Line Skipping]] (a variation of pixel binning, which only combines the photosites from one single line, and discards the data from the other lines in a 3x3 or 5x3 block, see below). It's easier to implement in hardware, but the main disadvantage of line skipping is poor performance with high-frequency details (severe aliasing/moire issues).+Most Canon cameras use [[/glossary/#Line Skipping]] (a variation of pixel binning, which only combines the photosites from one single line, and discards the data from the other lines in a 3x3 or 5x3 block, see below). It's easier to implement in hardware, but the main disadvantage of line skipping is poor performance with high-frequency details (severe [[/glossary/#aliasing]]/moire issues).
  
-Canon cameras generally use the following pixel binning modes:+**Canon cameras generally use the following pixel binning modes:**
  
 Pure pixel binning modes (without line skipping) - 5D Mark III: Pure pixel binning modes (without line skipping) - 5D Mark III:
  
 {{ https://a1ex.magiclantern.fm/bleeding-edge/lv-binning/5d3-lv-binning-cell-v2.png?100|}} {{ https://a1ex.magiclantern.fm/bleeding-edge/lv-binning/5d3-lv-binning-cell-v2.png?100|}}
-  * 3x3 binning: for every pixel, 9 photosites (3 lines x 3 columns) of the same [[#Bayer]] color are averaged together. Used on 5D Mark III in 1080p video modes. See figure -> +  * 3x3 binning: for every pixel, 9 photosites (3 lines x 3 columns) of the same [[/glossary/#Bayer]] color are averaged together. Used on 5D Mark III in 1080p video modes. See figure -> 
-  * 5x3 binning: for every pixel, 15 photosites (5 lines x 3 columns) of the same [[#Bayer]] color are averaged together. Used on 5D Mark III in 720p video modes.+  * 5x3 binning: for every pixel, 15 photosites (5 lines x 3 columns) of the same [[/glossary/#Bayer]] color are averaged together. Used on 5D Mark III in 720p video modes.
   * 1:1 crop (no binning, sometimes called "crop mode"). Used on all cameras when capturing a full resolution image. Also used on Canon cameras in x5/x10 zoom modes in LiveView.   * 1:1 crop (no binning, sometimes called "crop mode"). Used on all cameras when capturing a full resolution image. Also used on Canon cameras in x5/x10 zoom modes in LiveView.
  
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   * 5x3 column binning / line skipping. Used by most Canon EOS cameras to implement 720p video. For every line read out from the sensor, 4 lines are discarded (skipped).   * 5x3 column binning / line skipping. Used by most Canon EOS cameras to implement 720p video. For every line read out from the sensor, 4 lines are discarded (skipped).
  
-Pixel binning patterns will affect camera's [[#native resolution]] in video mode.+Pixel binning patterns will affect camera's [[/glossary/#native resolution]] in video mode.
  
-Custom binning modes enabled by Magic Lantern (currently available in some experimental versions of the [[#crop_rec]] module): +Custom binning modes enabled by Magic Lantern (currently available in some experimental versions of the [[/glossary/#crop_rec]] module): 
-  * 1x3 binning: a custom binning technique which operates on blocks of 1 line and 3 columns. It acts as a middle ground between 3x3 (1080p) and 1:1 (full resolution). This mode uses all photosites from the image sensor, by reading every single line, and does not have any noticeable aliasing/moire issues. Also known as [[#Anamorphic]].+ 
 +  * 1x3 binning: a custom binning technique which operates on blocks of 1 line and 3 columns. It acts as a middle ground between 3x3 (1080p) and 1:1 (full resolution). This mode uses all photosites from the image sensor, by reading every single line, and does not have any noticeable aliasing/moire issues. Also known as [[/glossary/#Anamorphic]].
   * 3x1 binning / line skipping: another custom binning technique, using blocks of 3 lines and 1 column, requiring the same data rate as with 1x3 binning. Not very useful in practice, because of the aliasing/moire issues.   * 3x1 binning / line skipping: another custom binning technique, using blocks of 3 lines and 1 column, requiring the same data rate as with 1x3 binning. Not very useful in practice, because of the aliasing/moire issues.
-{{ https://a1ex.magiclantern.fm/bleeding-edge/lv-binning/binmode-3x3-rcskip-extrememoire.png?100|}} +  * 3x3 line/column skipping: from each 3x3 group of photosites, only one photosite is read out; all others are discarded. The layout is a little unusual. [[https://a1ex.magiclantern.fm/bleeding-edge/lv-binning/extreme-moire.html|Extreme aliasing/moiré issues]].  See figure > {{ https://a1ex.magiclantern.fm/bleeding-edge/lv-binning/binmode-3x3-rcskip-extrememoire.png?100|}} 
-  * 3x3 line/column skipping: from each 3x3 group of photosites, only one photosite is read out; all others are discarded. See figure - the layout is a little unusual. [[https://a1ex.magiclantern.fm/bleeding-edge/lv-binning/extreme-moire.html|Extreme aliasing/moiré issues]].+
  
 FIXME: way too long (move to new page?) (agreed)\\ FIXME: way too long (move to new page?) (agreed)\\
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 -> [[ml>forum/index.php?topic=16516.0|ML Forum: Pixel binning patterns in LiveView]]\\ -> [[ml>forum/index.php?topic=16516.0|ML Forum: Pixel binning patterns in LiveView]]\\
 -> [[https://a1ex.magiclantern.fm/bleeding-edge/lv-binning/binning-modes.html|Simulation: 1x3 "column binning" vs 3x1 "line skipping" vs 3x3 binning/skipping]]\\ -> [[https://a1ex.magiclantern.fm/bleeding-edge/lv-binning/binning-modes.html|Simulation: 1x3 "column binning" vs 3x1 "line skipping" vs 3x3 binning/skipping]]\\
--> [[#Line Skipping]]\\ +-> [[/glossary/#Line Skipping]]\\ 
--> [[#Native Resolution]]\\ +-> [[/glossary/#Native Resolution]]\\ 
--> [[#crop_rec]]\\ +-> [[/glossary/#crop_rec]]\\ 
--> [[#Anamorphic]]\\+-> [[/glossary/#Anamorphic]]\\
pixel_binning.txt · Last modified: 2021/02/03 12:10 by Audionut