how to find the change in curve

i have plotted a curve on my image. The curve is shown in red. I want to find the jump in my curve with some good algroithm. The area in the curve where i want to detect jump is shown in blue. I have tried to find difference between two point to detect jump but that always does not return me the points in the curve i want(show in blue).

[Cedric]

But you have the red curve as e.g. a row vector already? If so, could you attach it?

[prashant singh]

Attaching row vector for the curve.

Answer 1

[Image Analyst]

Have you tried findchangepts()?

Answer 2

[Star Strider]

Try this:

D = load('ridx.mat');
ridx = D.ridx;
ridx = max(ridx)-ridx;
x = 1:length(ridx);

dt_ridx = detrend(ridx);
mask = dt_ridx > 27;

figure(1)
plot(x, ridx)
hold on
plot(x(mask), ridx(mask), '-r', 'LineWidth',1.2)
hold off
grid

Here mask is a logical vector that identifies the ‘jump’ region.