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− | [[Image:Hornetseye.jpg|thumb|320px|right|Logo of Hornetseye-library showing a hornet]]
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− | =Introduction=
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− | '''[http://www.wedesoft.demon.co.uk/hornetseye-api/ HornetsEye]''' is a [http://www.rubyist.net/~nobu/ruby/Ruby_Extension_Manual.html Ruby-extension] for real-time computer vision under GNU/Linux offering interfaces to do image- and video-I/O with [http://rmagick.rubyforge.org/ RMagick], [http://www.xinehq.de/ Xine], firewire digital camera ([http://damien.douxchamps.net/ieee1394/libdc1394/ DC1394]) and video for Linux ([http://www.exploits.org/v4l/ V4L]).
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− | '''[http://www.wedesoft.demon.co.uk/hornetseye-api/ HornetsEye]''' also is an attempt to use the Mimas library and create a ''minimalistic'' and ''consistent'' real-time computer vision library.
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− | * '''minimalistic''': The library is focused on real-time computer vision. Existing libraries are being made used of.
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− | * '''consistent''':: A non-redundant set of data-types is used. Also the library tries to stay consistent with existing libraries.
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− | | + | |
− | =Example=
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− | The example program performs two-dimensional object recognition with three degrees of freedom. This is a customised algorithm which only works on images showing a single object which can be detected using colour-segmentation. In a controlled environment however this algorithm can be very useful as it is easy to implement. It is also possible to optimise it for real-time applications.
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− | | + | |
− | <pre>
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− | #!/usr/bin/ruby
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− | # Detect location and rotation of an object using color-segmentation and
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− | # principal component analysis on resulting binary image.
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− | require 'hornetseye'
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− | require 'matrix'
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− | raise "Syntax: pcarecognition.rb [media resource location]" if ARGV.size != 1
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− | input = Hornetseye::XineInput.new( ARGV[0] )
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− | # Object is black.
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− | dominant = 0
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− | frame = 0
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− | old_eigenvector = Vector[ 1, 0 ]
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− | while input.status?
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− | # Read image.
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− | img = input.read_grey
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− | # Detect center and rotation of object using principal component analysis.
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− | # Assuming object has a principal axis (otherwise this approach fails).
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− | c = 0
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− | n = 0
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− | sum = [ 0, 0 ]
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− | squares = [ [ 0, 0 ], [ 0, 0 ] ]
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− | img.each do |v|
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− | if v & 0xE0 == dominant
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− | x = c % img.shape[1]
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− | y = c / img.shape[1]
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− | sum[ 0 ] += x
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− | sum[ 1 ] += y
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− | squares[ 0 ][ 0 ] += x * x
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− | squares[ 0 ][ 1 ] += x * y
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− | squares[ 1 ][ 0 ] += y * x
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− | squares[ 1 ][ 1 ] += y * y
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− | n += 1
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− | end
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− | c += 1
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− | end
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− | sum = Vector[*sum]
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− | squares = Matrix[*squares]
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− | center = sum * ( 1.0 / n )
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− | covariance = ( n * squares -
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− | sum.covector.transpose*sum.covector ) / ( n ** 2 ).to_f
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− | # "abs" is needed to deal with numerical errors.
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− | discriminant = ( covariance.trace ** 2 - 4 * covariance.determinant ).abs
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− | # Take largest eigenvalue. Eigenvalues are "0.5 * ( tr +- discriminant )"
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− | lambda1 = 0.5 * ( covariance.trace + Math.sqrt( discriminant ) )
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− | eigenspace = covariance - lambda1 * Matrix.unit( 2 )
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− | # Compute eigenvector by projecting basis-vectors.
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− | projected1 = eigenspace * Vector[1,0]
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− | projected2 = eigenspace * Vector[0,1]
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− | if projected1.r >= projected2.r
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− | projected = projected1 * ( 1.0 / projected1.r )
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− | else
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− | projected = projected2 * ( 1.0 / projected2.r )
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− | end
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− | eigenvector = Vector[ -projected[ 1 ], projected[ 0 ] ]
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− | # Resolv ambiguity by comparing with previous eigenvector.
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− | if old_eigenvector.inner_product( eigenvector ) < 0
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− | eigenvector = Vector[ projected[ 1 ], -projected[ 0 ] ]
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− | end
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− | old_eigenvector = eigenvector
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− | gc=Magick::Draw.new
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− | pointer=center+eigenvector*30
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− | gc.fill_opacity(0)
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− | gc.stroke('red').stroke_width(3)
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− | gc.circle(center[0],center[1],pointer[0],pointer[1])
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− | gc.line(center[0],center[1],pointer[0],pointer[1])
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− | result=img.to_magick
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− | gc.draw(result)
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− | result.to_hornetseye.save( ( "%08d" % frame ) + ".jpg" )
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− | frame += 1
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− | end
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− | </pre>
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− | {|align="center" | + | |
| |- | | |- |
− | |[[Image:Polygon134.jpg|thumb|320px|135th input frame acquired from the [http://vision.eng.shu.ac.uk/jan/polygon.avi test-video] showing a polygon]]||[[Image:Polyresult134.jpg|thumb|320px|Resulting image indicating position and orientation of the object's principal axis]] | + | |[[Image:AVA-Bristol-2008.jpg|thumb|240px|[http://vision.eng.shu.ac.uk/jan/ava-bristol-2008.pdf Poster] for the 2008 [http://hlsweb.dmu.ac.uk/ava/meetings/bristol2008.html AVA meeting] in Bristol]] |
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| + | |[[Image:Oscon08foils.jpg|240px|thumb|Conference presentation [http://vision.eng.shu.ac.uk/jan/oscon08-foils.pdf Real-time Computer Vision With Ruby] presented at [http://en.oreilly.com/oscon2008/ OSCON 2008]]] |
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| |} | | |} |
− | | + | =Introduction= |
− | Thanks to [http://www.mach.uni-karlsruhe.de/seite10513.php Prof. Dr.-Ing. Christoph Stiller] for pointing out this algorithm.
| + | '''[http://www.wedesoft.demon.co.uk/hornetseye-api/ HornetsEye]''' is a Ruby-extension for developing video processing and real-time computer vision software under GNU/Linux offering interfaces to do image- and video-I/O with RMagick, Xine, firewire digital camera, and video for Linux. A new class of unprecedented solutions and a new way of working becomes conceivable when applying a dynamically typed, object-oriented language like Ruby to computer vision. |
− | | + | |
− | =Downloads= | + | |
− | ==HornetsEye-0.10==
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− | * [[Image:Hornetseye.jpg|48px]] '''Download [http://rubyforge.org/frs/?group_id=2714 HornetsEye-0.10] released on February 1st 2007'''
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− | * [http://vision.eng.shu.ac.uk/jan/polygon.avi test-video with polygon]
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− | | + | |
− | ===Release Notes===
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− | See http://www.wedesoft.demon.co.uk/hornetseye-api/ for installation instructions.
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− | | + | |
− | ===Change log===
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− | * Made display method accept more element-types.
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− | * Normalisation also works on blank image.
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− | | + | |
− | ==Older releases==
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− | See [http://rubyforge.org/frs/?group_id=2714 Hornetseye page at Rubyforge] for older releases.
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| =See Also= | | =See Also= |
− | * [[Mimas]] | + | * [[Interactive Presentation Software]] |
| + | * [[Just-in-time compiler]] |
| + | * [[Lucas-Kanade tracker]] |
| + | * [[Hypercomplex Wavelets]] |
| + | * [[Qt4-QtRuby installer for Microsoft Windows]] |
| + | * [[TEM vision software]] |
| + | * [[Image:Mimasanim.gif|40px]] [[Mimas]] |
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| =External Links= | | =External Links= |
− | * [http://www.wedesoft.demon.co.uk/hornetseye-api/ Hornetseye homepage] | + | * [[Image:Hornetseye.png|48px]] [http://www.wedesoft.demon.co.uk/hornetseye-api/ HornetsEye homepage] |
− | * [http://rubyforge.org/projects/hornetseye/ Hornetseye at Rubyforge] | + | * [[Image:Rubyforge.png|75px]] [http://rubyforge.org/projects/hornetseye/ HornetsEye at Rubyforge] |
− | * [[Image:Ruby.png|25px]] [http://www.ruby-lang.org/ Ruby] programming language | + | * [[Image:Sourceforge.png|58px]] [http://sourceforge.net/projects/hornetseye/ HornetsEye at Sourceforge] |
− | * [http://www.csie.ntnu.edu.tw/~bbailey/Moments%20in%20IP.htm Moments in image processing] | + | * [[Image:Swig.png|48px]] [http://www.swig.org/ SWIG] (Simplified Wrapper and Interface Generator) |
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| + | {{AddThis}} |
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| [[Category:Projects]] | | [[Category:Projects]] |
| [[Category:Nanorobotics]] | | [[Category:Nanorobotics]] |