How to find the x-axis of modulation transfer function of a gaussian curve in MATLAB?

9 次查看(过去 30 天)
I am trying to find modulation transfer function of a gaussian curve by using MATLAB. The gaussian curve is as below:
x- axis is distance(form -15mm to 15mm) and y axis is count(Magnitude). I used the following code to find find fourier transfrom of gaussian curve.
FFT_y = fft(y); %take fourier transform
FF_mag = abs(FFT_y )/(length(FFT_y )); %find magnitude
FF_mag = (FF_mag-min(FF_mag))./(max(FF_mag)-min(FF_mag)); %normalize magnitude
I cropped FF_mag by using the following codes
FF_mag_nw = FF_mag(1:(length(FF_y)/32));
plot(FF_mag_nw);
I used 32 in above code to get main portion of graph and I got MTF plot as below:
I am confused about X-axis. What will be the range of X-axis in per mm? Can anyone help me give an idea to calculate X-axis of MTF plot?
Thanks in Advance! Manu
  2 个评论
Cinzia Emmanuello
Cinzia Emmanuello 2020-3-13
Dear Manu and whoever comes to this question while googling stuff,
I do not know in which field you are working in (you could have specified it) but anyway the x-axis is in the spatial frequency domain (line pairs/mm). The axis is not in mm anymore, you just applied a Fourier transformation.
Regards,
Cinzia
Signal Express
Signal Express 2022-4-15
@Cinzia Emmanuello ; @madhan ravi and @Nikhil Sonavane Hello sirs/madam, Is it possible to determine the point spread function and modulation transfer function of an image using matlab? If so, could you guide me through it? I have an image from a microscope, I have determined the resolution by camparing it with the USAF 1951 resolution test chart but I dont know how to proceed further. I must confess, I am a novice in matlab!

请先登录,再进行评论。

回答(1 个)

Nikhil Sonavane
Nikhil Sonavane 2019-8-2
Referring to the last plot function used-
plot(FF_mag_nw);
The above command will plot FF_mag_nw which is a one-dimensional matrix against its row number as its x co-ordinate. X-axis in the plot will span from 1 to length(FF_y)/32. Hence, x-axis in your plot will only signify the total number of data points in FF_mag_nw.

类别

Help CenterFile Exchange 中查找有关 Geometric Transformation and Image Registration 的更多信息

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by