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( ] I& u: M0 F( I' d 废话不多说,没什么技术含量,因为下面的代码是matlab中自带的转换函数。在这里贴出来只是为了方便以后复习、研究其转换的算法:
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HSV空间:分别是H(色调)——S(饱和度)——V(亮度)
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强度和亮度差不多是一个概念。
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饱和度代表的是渗入白光的数量级,白光越多,饱和度越小,白光越少,饱和度越大,表示颜色的纯度更大。
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' Y* C \0 ^: x8 ] }下面是代码:
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rgb2hsv.m9 d5 w# t0 q3 b& _6 z+ t
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- function [h,s,v] = rgb2hsv(r,g,b)
- %RGB2HSV Convert red-green-blue colors to hue-saturation-value.
- % H = RGB2HSV(M) converts an RGB color map to an HSV color map.
- % Each map is a matrix with any number of rows, exactly three columns,
- % and elements in the interval 0 to 1. The columns of the input matrix,
- % M, represent intensity of red, blue and green, respectively. The
- % columns of the resulting output matrix, H, represent hue, saturation
- % and color value, respectively.
- %
- % HSV = RGB2HSV(RGB) converts the RGB image RGB (3-D array) to the
- % equivalent HSV image HSV (3-D array).
- %
- % CLASS SUPPORT
- % -------------
- % If the input is an RGB image, it can be of class uint8, uint16, or
- % double; the output image is of class double. If the input is a
- % colormap, the input and output colormaps are both of class double.
- %
- % See also HSV2RGB, COLORMAP, RGBPLOT.
- % Undocumented syntaxes:
- % [H,S,V] = RGB2HSV(R,G,B) converts the RGB image R,G,B to the
- % equivalent HSV image H,S,V.
- %
- % HSV = RGB2HSV(R,G,B) converts the RGB image R,G,B to the
- % equivalent HSV image stored in the 3-D array (HSV).
- %
- % [H,S,V] = RGB2HSV(RGB) converts the RGB image RGB (3-D array) to
- % the equivalent HSV image H,S,V.
- %
- % See Alvy Ray Smith, Color Gamut Transform Pairs, SIGGRAPH '78.
- % Copyright 1984-2006 The MathWorks, Inc.
- % $Revision: 5.15.4.3 $ $Date: 2010/08/23 23:13:14 $
- switch nargin
- case 1,
- if isa(r, 'uint8'),
- r = double(r) / 255;
- elseif isa(r, 'uint16')
- r = double(r) / 65535;
- end
- case 3,
- if isa(r, 'uint8'),
- r = double(r) / 255;
- elseif isa(r, 'uint16')
- r = double(r) / 65535;
- end
- if isa(g, 'uint8'),
- g = double(g) / 255;
- elseif isa(g, 'uint16')
- g = double(g) / 65535;
- end
- if isa(b, 'uint8'),
- b = double(b) / 255;
- elseif isa(b, 'uint16')
- b = double(b) / 65535;
- end
- otherwise,
- error(message('MATLAB:rgb2hsv:WrongInputNum'));
- end
- threeD = (ndims(r)==3); % Determine if input includes a 3-D array
- if threeD,
- g = r(:,:,2); b = r(:,:,3); r = r(:,:,1);
- siz = size(r);
- r = r(:); g = g(:); b = b(:);
- elseif nargin==1,
- g = r(:,2); b = r(:,3); r = r(:,1);
- siz = size(r);
- else
- if ~isequal(size(r),size(g),size(b)),
- error(message('MATLAB:rgb2hsv:InputSizeMismatch'));
- end
- siz = size(r);
- r = r(:); g = g(:); b = b(:);
- end
- v = max(max(r,g),b);
- h = zeros(size(v));
- s = (v - min(min(r,g),b));
- z = ~s;
- s = s + z;
- k = find(r == v);
- h(k) = (g(k) - b(k))./s(k);
- k = find(g == v);
- h(k) = 2 + (b(k) - r(k))./s(k);
- k = find(b == v);
- h(k) = 4 + (r(k) - g(k))./s(k);
- h = h/6;
- k = find(h < 0);
- h(k) = h(k) + 1;
- h=(~z).*h;
- k = find(v);
- s(k) = (~z(k)).*s(k)./v(k);
- s(~v) = 0;
- if nargout<=1,
- if (threeD || nargin==3),
- h = reshape(h,siz);
- s = reshape(s,siz);
- v = reshape(v,siz);
- h=cat(3,h,s,v);
- else
- h=[h s v];
- end
- else
- h = reshape(h,siz);
- s = reshape(s,siz);
- v = reshape(v,siz);
- end
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hsv2rgb.m
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- function [rout,g,b] = hsv2rgb(hin,s,v)
- %HSV2RGB Convert hue-saturation-value colors to red-green-blue.
- % M = HSV2RGB(H) converts an HSV color map to an RGB color map.
- % Each map is a matrix with any number of rows, exactly three columns,
- % and elements in the interval 0 to 1. The columns of the input matrix,
- % H, represent hue, saturation and value, respectively. The columns of
- % the resulting output matrix, M, represent intensity of red, blue and
- % green, respectively.
- %
- % RGB = HSV2RGB(HSV) converts the HSV image HSV (3-D array) to the
- % equivalent RGB image RGB (3-D array).
- %
- % As the hue varies from 0 to 1, the resulting color varies from
- % red, through yellow, green, cyan, blue and magenta, back to red.
- % When the saturation is 0, the colors are unsaturated; they are
- % simply shades of gray. When the saturation is 1, the colors are
- % fully saturated; they contain no white component. As the value
- % varies from 0 to 1, the brightness increases.
- %
- % The colormap HSV is hsv2rgb([h s v]) where h is a linear ramp
- % from 0 to 1 and both s and v are all 1's.
- %
- % See also RGB2HSV, COLORMAP, RGBPLOT.
- % Undocumented syntaxes:
- % [R,G,B] = HSV2RGB(H,S,V) converts the HSV image H,S,V to the
- % equivalent RGB image R,G,B.
- %
- % RGB = HSV2RGB(H,S,V) converts the HSV image H,S,V to the
- % equivalent RGB image stored in the 3-D array (RGB).
- %
- % [R,G,B] = HSV2RGB(HSV) converts the HSV image HSV (3-D array) to
- % the equivalent RGB image R,G,B.
- % See Alvy Ray Smith, Color Gamut Transform Pairs, SIGGRAPH '78.
- % Copyright 1984-2011 The MathWorks, Inc.
- if nargin == 1 % HSV colormap
- threeD = ndims(hin)==3; % Determine if input includes a 3-D array
- if threeD,
- h = hin(:,:,1); s = hin(:,:,2); v = hin(:,:,3);
- else
- h = hin(:,1); s = hin(:,2); v = hin(:,3);
- end
- elseif nargin == 3
- if ~isequal(size(hin),size(s),size(v)),
- error(message('MATLAB:hsv2rgb:InputSizeMismatch'));
- end
- h = hin;
- else
- error(message('MATLAB:hsv2rgb:WrongInputNum'));
- end
- h = 6.*h;
- k = floor(h);
- p = h-k;
- t = 1-s;
- n = 1-s.*p;
- p = 1-(s.*(1-p));
- % Processing each value of k separately to avoid simultaneously storing
- % many temporary matrices the same size as k in memory
- kc = (k==0 | k==6);
- r = kc;
- g = kc.*p;
- b = kc.*t;
- kc = (k==1);
- r = r + kc.*n;
- g = g + kc;
- b = b + kc.*t;
- kc = (k==2);
- r = r + kc.*t;
- g = g + kc;
- b = b + kc.*p;
- kc = (k==3);
- r = r + kc.*t;
- g = g + kc.*n;
- b = b + kc;
- kc = (k==4);
- r = r + kc.*p;
- g = g + kc.*t;
- b = b + kc;
- kc = (k==5);
- r = r + kc;
- g = g + kc.*t;
- b = b + kc.*n;
- if nargout <= 1
- if nargin == 3 || threeD
- rout = cat(3,r,g,b);
- else
- rout = [r g b];
- end
- rout = bsxfun(@times, v./max(rout(:)), rout);
- else
- f = v./max([max(r(:)); max(g(:)); max(b(:))]);
- rout = f.*r;
- g = f.*g;
- b = f.*b;
- end
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