Extract data from an grayscale image

I need to extract data from a sequence of image frames (extracted from a high-speed schlieren video in .mraw format) to perform Dynamic Mode Decomposition (DMD) and Fast Fourier Transform (FFT) analysis. The goal is to analyze the unsteady shock structures on the object by selecting a Region of Interest (ROI) within the images. Please help me write a MATLAB script that processes these frames, performs DMD and FFT analysis, and extracts the corresponding frequency and amplitude data from the selected ROI.

[Walter Roberson]

Two ways to read mraw are mentioned at https://www.mathworks.com/matlabcentral/answers/582314-phantom-cine-format-and-photron-mraw#answer_893440

[solleti prabhakarchary]

I had extracted frames from mraw file. I need to perform DMD analysis, find DMD modes and FFT analysis to extract frequency vs amplitude and findpeaks.