The most common method is to select an area, and measure total space. Then total space divided by number of fringes to get the d value. to confirmed the obtained value, compare the obtained value with XRD d values ( with high concentration provided by XRD data d space Value). As shown in the Fig the total space is 1.011nm which is divided by 5 because each peak demonstrate one fringe so the final value is 0.202 nm

you can also follow the following paper

https://doi.org/10.1016/j.electacta.2018.12.053

If you have HRTEM image, try FFT transformation and you get frequency pattern alike electron diffraction pattern. Then process FFT pattern in the same way as electron diffraction pattern.

Hi Muhammad Sufyan Javed

I hope, All your doubts will be cleared in only 8 minutes.