Bit plane

<h2 id="applications">Applications</h2>
<h3>Media file formats</h3>
<p>As an example, in <a href="/facts/Pulse-code_modulation/5gdfjtH3">PCM</a> sound <a href="/facts/Code/CSntvnEo">encoding</a> the first bit in the sample denotes the sign of the function, or in other words defines the half of the whole <a href="/facts/Amplitude/aEckuXJM">amplitude</a> values range, and the last bit defines the precise value. Replacement of more significant bits result in more distortion than replacement of less significant bits. In lossy <a href="/facts/Data_compression/gMFuY4FT">media compression</a> that uses bit-planes it gives more freedom to encode less significant bit-planes and it is more critical to preserve the more significant ones.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a>
</p><p>As illustrated in the image above, the early bitplanes, particularly the first, may have constant runs of bits, and thus can be efficiently encoded by <a href="/facts/Run-length_encoding/3k6x9afM">run-length encoding</a>. This is done (in the transform domain) in the <a href="/facts/Progressive_Graphics_File/qqE9tEaF">Progressive Graphics File</a> image format, for instance.
</p>
<h3>Bitmap displays</h3>
<p>Some computers displayed graphics in <a href="/facts/Planar_(computer_graphics)/v4U9TFIn">bit-plane format</a>, most notably PC with <a href="/facts/Enhanced_Graphics_Adapter/VFU5QRyp">EGA</a> graphics card, the <a href="/facts/Amiga/60B3A9of">Amiga</a> and <a href="/facts/Atari_ST/9GsYSlaM">Atari ST</a>, contrasting with the more common <a href="/facts/Packed_pixel/uUHfyGGG">packed format</a>. This allowed certain classes of image manipulation to be performed using bitwise operations (especially by a <a href="/facts/Blitter/P9v4cAld">blitter</a> chip), and parallax scrolling effects.
</p>
<h3>Video motion estimation</h3>
<p>Some <a href="/facts/Motion_estimation/FF2TIndo">motion estimation</a> algorithms can be performed using bit planes (e.g. after the application of a filter to turn salient edge features into binary values).<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> This can sometimes provide a good enough approximation for correlation operations with minimal computational cost. This relies on an observation that the spatial information is more significant than the actual values. Convolutions may be reduced to <a href="/facts/Bit_shift/0gkqnUda">bit shift</a> and <a href="/facts/Popcount/dJIW7qg4">popcount</a> operations, or performed in dedicated hardware.
</p>
<h3>Neural networks</h3>
<p>Bitplane formats may be used for passing images to <a href="/facts/Spiking_neural_networks/DeT3wPPV">Spiking neural networks</a>, or low precision approximations to <a href="/facts/Artificial_neural_network/6V1jMlkx">neural networks</a>/<a href="/facts/Convolutional_neural_networks/kHEdnmGU">convolutional neural networks</a>.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a>
</p>
<h2 id="programs">Programs</h2>
<p>Many image processing packages can split an image into bit-planes. Open source tools such as Pamarith from <a href="/facts/Netpbm/JnAKxh8B">Netpbm</a> and Convert from <a href="/facts/ImageMagick/sIC3ycHo">ImageMagick</a> can be used to generate bit-planes.
</p>
<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Color_depth/0X7zI9BP">Color depth</a></li>
<li><a href="/facts/Planar_(computer_graphics)/v4U9TFIn">Planar</a></li>
<li><a href="/facts/Binary_image/qaKaPntY">Binary image</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>"Bit Plane". PC Magazine. Archived from the original on 2012-10-07. Retrieved 2007-05-02. <a href="https://web.archive.org/web/20121007084142/http://www.pcmag.com/encyclopedia_term/0%2C2542%2Ct%3Dbit+plane%26i%3D38689%2C00.asp" target="_blank">https://web.archive.org/web/20121007084142/http://www.pcmag.com/encyclopedia_term/0%2C2542%2Ct%3Dbit+plane%26i%3D38689%2C00.asp</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>"Bit Plane". FOLDOC. Retrieved 2007-05-02. <a href="http://foldoc.org/foldoc.cgi?bit+plane" target="_blank">http://foldoc.org/foldoc.cgi?bit+plane</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Strutz, Tilo (2001). "Fast Noise Suppression for Lossless Image Coding". Proceedings of Picture Coding Symposium (PCS'2001), Seoul, Korea. Retrieved 2008-01-15. <a href="http://citeseer.ist.psu.edu/strutz01fast.html" target="_blank">http://citeseer.ist.psu.edu/strutz01fast.html</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>Cho, Chuan-Yu; Chen, Hong-Sheng; Wang, Jia-Shung (July 2006). "Smooth Quality Streaming With Bit-Plane Labelling". Visual Communications and Image Processing (abstract). Visual Communications and Image Processing 2005. 5690. The International Society for Optical Engineering: 2184–2195. Bibcode:2005SPIE.5960.2184C. doi:10.1117/12.633501. S2CID 62549171. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>"bitlane motion estimation". CiteSeerX 10.1.1.16.1755. <a href="/wiki/CiteSeerX_(identifier)" target="_blank">/wiki/CiteSeerX_(identifier)</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>Rastegari, Mohammad; Ordonez, Vicente; Redmon, Joseph; Farhadi, Ali (2016). "xnor net". arXiv:1603.05279 [cs.CV]. <a href="/wiki/ArXiv_(identifier)" target="_blank">/wiki/ArXiv_(identifier)</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
</ol>

Bit plane open-in-new

Bit plane