Assigning a colormap to bwlabel image representing imageprops

Hello,

I would like to apply a colormap to a bwlabel image representing max axis length extracted by imageprops (max axis <50) of objects min - max (0 - 50) value.

The idea would be that the colormap would display the range of values on the image rather than simply a pseudorandom shuffle of colors.

I'd also like to be able to display an accompanying histogram of the binary objects with the same colormap arrangement.

How might this be achieved? At the moment I have the following which displays the pseudorandom colors

    labelmax = bwlabel(keeperMaxImage, 8);

      MaxRGB = label2rgb(L,'hot',[.5 .5 .5], 'shuffle');
      figure, imshow(MaxRGB), title('Max Axis length - color ramp denotes range    of lengths');

figure, hist(M_axis, 100), title('Max');

Kind Regards

Ciaran

Answer 1

[Sean de Wolski]

Here's how I'd do it. There is probably a more elegant way:

%An image
I = imread('rice.png');
X = I>140; %binary
CC = bwconncomp(X); %Connected components
mal = regionprops(CC,'Orientation'); %Plug in MajorAxisLength here.
mal = vertcat(mal(:).Orientation);   %Plug in MajorAxisLength here.
[~,idx] = histc(mal,0:ceil(max(mal)));  %Which bin?
L = zeros(CC.ImageSize); %preallocate
for ii = 1:CC.NumObjects
  L(CC.PixelIdxList{ii}) = idx(ii);    %fill in indices
end
cmap = jet(max(idx));  %a colormap
Lrgb = label2rgb(L,cmap); %build rgb image
imshow(Lrgb)

I used 'Orientation' instead of 'MajorAxisLength' because I couldn't think of a shipped image where that was distinguishing.

[Ciaran Robb]

That's excellent, thank you very much!