calculate phase angle from image and validate it, Diff b/w phase and phase spectrum?

I am working on a acoustic microscope

What is the difference between phase and phase spectrum?

I have a 2d image 360x360 This image has been created using capturing amplitude of the reflected wave.

I want to calculate the phase angle of this image

My attempt(saw this Image reconstruction only by its phase or magnitude - MATLAB Answers - MATLAB Central (mathworks.com)):

image = rgb2gray(imread('coin.jpg')); 
F = fft2(double(image));
F_Mag = abs(F);
F_Phase = exp(1i*angle(F));
% reconstructin
I_Mag = ifft2(log(F_Mag+1));
I_Phase = ifft2(F_Phase);
% Calculate limits for plotting
I_Mag_min = min(min(abs(I_Mag)));
I_Mag_max = max(max(abs(I_Mag)));
I_Phase_min = min(min(abs(I_Phase)));
I_Phase_max = max(max(abs(I_Phase)));
% Display reconstructed images
subplot(121),imagesc(abs(I_Mag),[I_Mag_min I_Mag_max]), colormap gray 
title('reconstructed image only by Magnitude');
subplot(122),imagesc(abs(I_Phase),[I_Phase_min I_Phase_max]), colormap gray 
title('reconstructed image only by Phase');
phase=rad2deg(angle(I_Phase));

But I'm not sure this I'm getting is phase or not?

How to validate this?