how to plot histogram of hue value in polar ?

Hi

i wants to plot a histogram of hue values in polar . in my 1st image i have plotted histogram of hue values . and now i would like to plot it on polar as shown in figure 2.

please help me .

Answer 1

[Image Analyst]

I just adapted Doug's code to use a sample image and I got this:

See code attached below in blue text.

[SAM]

Thanks a lot, u r too good in programing @ * _ Image Analyst _ * .......

[Image Analyst]

And Doug - he did most of the work.

Answer 2

[Doug Hull]

clear
clc
clf

z = peaks(300);
r = z(:,150);
r = r-min(r);
r = r/max(r);

n = numel(r)

cmap = jet(n)

drawWheel(r*0.8,cmap)

Save this file first though:

function drawWheel(r, cmap)
if (any(r > 1) | any(r < 0))
    error('R must be a vector of values between 0 and 1')
end

if numel(r) ~= size(cmap,1)
    error('Length of r and cmap must be the same')
end

n = numel(r);
innerRadius =  80;
outerRadius = 100;

angles = linspace(0,2*pi,n+1);
newR = innerRadius*(1-r);

for i = 1:n;
    drawSpoke(innerRadius, outerRadius, angles(i), angles(i+1), cmap(i,:))

      drawSpoke(newR(i)    , innerRadius, angles(i), angles(i+1), cmap(i,:))
  end

line(0,0,'marker','o')
line(cos(angles)*outerRadius, sin(angles)*outerRadius, 'LineWidth', 3, 'Color', 'k')
line(cos(angles)*innerRadius, sin(angles)*innerRadius, 'LineWidth', 3, 'Color', 'k')
axis equal

function h = drawSpoke(ri,ro,thetaStart,thetaEnd,c)

xInnerLeft  = cos(thetaStart) * ri;
xInnerRight = cos(thetaEnd)   * ri;
xOuterLeft  = cos(thetaStart) * ro;
xOuterRight = cos(thetaEnd)   * ro;

yInnerLeft  = sin(thetaStart) * ri;
yInnerRight = sin(thetaEnd)   * ri;
yOuterLeft  = sin(thetaStart) * ro;
yOuterRight = sin(thetaEnd)   * ro;

X = [xInnerLeft, xInnerRight, xOuterRight xOuterLeft];
Y = [yInnerLeft, yInnerRight, yOuterRight yOuterLeft];

h = patch(X,Y,c);
set(h,'edgeColor', 'none')

[SAM]

Dear Doug Hull

thanks for your answer but i want my histogram should come in the circle.

clc
close all
clear all
ima = imread('image.jpg');
ima1=rgb2hsv(ima);
ima2=ima1(:,:,1);
imhist(ima2);
polar((imhist(ima2)));

but it not giving me the desired output. i am not bother about that hsv wheel but i want my polar should show the hue value of histogram as show in inside of the wheel.

please help me.......

Answer 3

[Abdoo]

This small example to compere between three plots Hue from images and save the data in excel file.