Axes get reverse while overlaying line plot on image

Hi everyone, I have problem with overlying line plot on image. I have corrected the reversed Y-axis, but the line plot is still wrong i.e plotted with reversed axes (as seen on data cursor). I have attached both real line plot (second fig) and same line plot getting falsely plotted when overlayed on image. plz help me on this, thanks

img = imread('wave.png')

min_y = 0

max_y =18

min_x = 985;

max_x = 4500

imagesc([min_x max_x] ,[min_y max_y],img);

truesize;

hold on;

plot(wav, N)

yTicks = get(gca,'YTick');

yTicks_reverse = sort(yTicks,2,'descend');

set(gca,'YTickLabel',num2str(yTicks_reverse.'));

set(gca,'YDir','reverse'); <<

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Answer 1

[Jan]

The tick labels are strings. Sorting them might lead to unexpected results, when they have a different number of digits - characters!

You reverse the tick labels and the YDir afterwards. This seems to be confusing.

Answer 2

[Image Analyst]

I think the problem might be you're passing in the x and y axes to imagesc(). These might be opposite to that of a normal image, which has the y origin (y = row or line #1) at the top, instead of having y at the bottom like plot usually does. Try reversing the y array you send in to imagesc() and see if that helps.

imagesc([min_x, max_x] ,[max_y, min_y],img);

Or just use imshow() if you have the Image Processing Toolbox. Or set(gca, 'ydir', 'reverse') or set(gca, 'ydir', 'normal') at the critical time(s).