Calculation volumen using differential radar interferometry

Hello, I am currently writing an article called “Calculation of the volume of material extracted when carrying out illegal gold mining in the first half of 2023 using differential radar interferometry.” To perform the calculation, generate the interferogram by performing the steps as follows: 1. Corregistration. 2. Interphoregram, 3. Deburts, 4. Tophographic Phase Remova 5. Goldstein Phase Filtering. 6. Shaphu, 7. Phase Displacement. 8. Range doppler terrain correction.

This resulted in images generated at different times, in which the pixel values ​​are all negative, understanding this result, if there has been loss of ground in the area.

To find the volume of each study area, I am performing the following operation. 10*10/pixel value.

where 10 is the pixel value of the SAR image and I divide it by the result of each pixel.

I don’t know if I am doing the procedure correctly, I would like you to suggest me about the procedure, thank you very much.