Question

I have 1024 X 256 polar data (rows – radius, columns angle) that I need to plot as an image. There is an m-file I got from the file-exchange that can do this (clickhere). However, it is really slow for large images. I believe there is a fast way to do this using the surf function that I am struggling with. (See code below)

data = data; % load any polar data

depth = 4.5; %imaging depth in mm

offset = 0.5;

theta = [(0:2*pi/size(data,2):2*pi-1/size(data,2))]*180/pi;

rho = [0:(depth-offset)/size(data,1):(depth-offset)-1/size(data,1)] + offset;

[THETA,RR] = meshgrid(theta,rho);

[A,B] = pol2cart(THETA,RR);

figure

surf(A,B,data,'edgecolor','none'),

view(0,90)

xlabel('x [mm]')

ylabel('y [mm]')

axis tight

The result appears to be incorrect.

Any idea what I am doing wrong?
Thanks!

Answer 1

Yep, your problem is simple:

pol2cart Transform polar to Cartesian coordinates.
    [X,Y] = pol2cart(TH,R) transforms corresponding elements of data
    stored in polar coordinates (angle TH, radius R) to Cartesian
    coordinates X,Y.  The arrays TH and R must the same size (or
    either can be scalar).  ***TH must be in radians***.

Solution: Remove the 180/pi