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

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