Display Phase and Magnitude Plots of a Complex Image from the IMAQ FFT Function

Updated May 19, 2020

Issue Details

How do I display the phase and magnitude plots of a complex image after taking the FFT of it?

Solution

The process for converting your image into phase and magnitude plots after taking an FFT of it is to use the following functions:

IMAQ FFT >> (Optional) IMAQ ComplexFlipFrequency >> IMAQ ComplexPlaneToImage (Once for phase and once for magnitude) 

 


The code above shows the functions on the block diagram in the correct order. This will give you the appropriate phase and magnitude plots. The IMAQ FFT function accepts any image as an input and outputs a complex image. The reason for the optional flip frequency is that the display of a complex image has the zero and low frequency data at the center, which differs from how it is stored in memory where the quadrants are flipped. To get this to display as it is in memory use the IMAQ ComplexFlipFrequency function.

Additional Information

For information on displaying the complex image generated by the FFT of the original image refer to the IMAQ Vision Concepts Manual section on FFT Display.