Find all the highest pixel values using ismember

The authorSteve Eddins,June 8, 2022

29 times view | (over the past 30 days)0A great|Two comments

            Today 's post shows how to use
            ismember
            方便地定位图像中的所有像素值最高的。例如,在接下来的霍夫变换形象,什么是20值最高,
            Where are all the pixels that have those values
            ?
           

            I got the idea from some example code written by Image Processing Toolbox writer Megan Mancuso. Megan says she got the idea to use
            ismember
            This way the from
            Ahmed 's answer
            On MATLAB Answers.
           

            Here 's where the Hough transform image above comes from.
           

              A = imread (“gantrycrane.png”);
             

              Imshow (A)
             

              Bw = edge (rgb2gray (A),"Canny");
             

              Imshow (bw)
             

              / H, T, R = hough (bw);
             

              imshow (H, [], XData = T, YData = R)
             

              daspectauto
             

              The axis在
             

            Now let 's sort to figure out the highest values of 20
            H.
            .
           

              Sorted_H_values = sort (H (:),"Descend");
             

              Highest_H_values = sorted_H_values (1:20)
             

                  Highest_H_values =
                  20 x 1
                 

                  293 250 209 205 182 177 173 172 171 168

            Finally, I "l l use
            ismember
            To compute a binary image showing all the elements of H that have one of those 20 highest values. (And I "l l use
            xlim
            The and
            ylim
            To zoom in so that we can see what of those elements clearly.)
           

              Mask_20_highest_values = ismember (H, highest_H_values);
             

              Imshow (mask_20_highest_values XData = T, YData = R)
             

              daspectauto
             

              The axis在
             

              Xlim ([60] - 10)
             

              ylim(452年[141])
             

            Any element - wise logical function, to the as
            ismember
            , can be 2 in this way to produce a binary image, So add this to your bag of tricks MATLAB!
           

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