#
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# The Python Imaging Library.
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# $Id$
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#
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# image enhancement classes
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#
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# For a background, see "Image Processing By Interpolation and
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# Extrapolation", Paul Haeberli and Douglas Voorhies. Available
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# at http://www.sgi.com/grafica/interp/index.html
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#
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# History:
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# 1996-03-23 fl Created
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# 2009-06-16 fl Fixed mean calculation
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#
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# Copyright (c) Secret Labs AB 1997.
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# Copyright (c) Fredrik Lundh 1996.
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#
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# See the README file for information on usage and redistribution.
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#
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import Image, ImageFilter, ImageStat
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class _Enhance:
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##
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# Returns an enhanced image. The enhancement factor is a floating
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# point value controlling the enhancement. Factor 1.0 always
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# returns a copy of the original image, lower factors mean less
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# colour (brightness, contrast, etc), and higher values more.
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# There are no restrictions on this value.
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#
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# @param factor Enhancement factor.
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# @return An enhanced image.
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def enhance(self, factor):
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return Image.blend(self.degenerate, self.image, factor)
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##
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# Color enhancement object.
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# <p>
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# This class can be used to adjust the colour balance of an image, in
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# a manner similar to the controls on a colour TV set. An enhancement
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# factor of 0.0 gives a black and white image, a factor of 1.0 gives
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# the original image.
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class Color(_Enhance):
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"Adjust image colour balance"
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def __init__(self, image):
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self.image = image
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self.degenerate = image.convert("L").convert(image.mode)
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##
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# Contrast enhancement object.
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# <p>
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# This class can be used to control the contrast of an image, similar
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# to the contrast control on a TV set. An enhancement factor of 0.0
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# gives a solid grey image, factor 1.0 gives the original image.
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class Contrast(_Enhance):
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"Adjust image contrast"
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def __init__(self, image):
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self.image = image
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mean = int(ImageStat.Stat(image.convert("L")).mean[0] + 0.5)
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self.degenerate = Image.new("L", image.size, mean).convert(image.mode)
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##
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# Brightness enhancement object.
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# <p>
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# This class can be used to control the brighntess of an image. An
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# enhancement factor of 0.0 gives a black image, factor 1.0 gives the
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# original image.
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class Brightness(_Enhance):
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"Adjust image brightness"
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def __init__(self, image):
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self.image = image
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self.degenerate = Image.new(image.mode, image.size, 0)
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##
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# Sharpness enhancement object.
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# <p>
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# This class can be used to adjust the sharpness of an image. The
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# enhancement factor 0.0 gives a blurred image, 1.0 gives the original
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# image, and a factor of 2.0 gives a sharpened image.
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class Sharpness(_Enhance):
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"Adjust image sharpness"
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def __init__(self, image):
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self.image = image
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self.degenerate = image.filter(ImageFilter.SMOOTH)
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