Relative radiometric normalization using pseudo invariant features (PIF) in Google Earth Engine can be done by following these steps:

1. Add the input imagery to Earth Engine.

2. Identify potential PIFs by exploring the image and selecting features that do not change significantly in the image over the time period of interest.

3. Label PIFs and assign each one a unique identifier.

4. Select the sample points to be used for radiometric normalization.

5. Calculate the mean and standard deviation of the radiometric values for the sample points.

6. Calculate the radiometric value of the PIFs in the input imagery.

7. Calculate the normalization factor for each PIF by dividing the radiometric value of the PIF by the mean and standard deviation of the sample points.

8. Apply the normalization factor to the input imagery in order to achieve relative radiometric normalization using the PIFs.

Script:

// Define a function to calculate the relative radiometric normalization using PIF

var relativeRadiometricNormalization = function(image){

// Calculate the normalization factor

var normalizationFactor = image.normalizedDifference(['B7','B5']).select('B7');

// Select the bands to be used for the normalization

var bands = ['B2','B3','B4','B5','B6','B7'];

// Map the normalization over the bands

var normalized = image.select(bands).multiply(normalizationFactor).divide(100);

// Return the normalized image

return normalized;

};

// Apply the function to the image

var normalizedImage = relativeRadiometricNormalization(image);

Hope this will work.

Harikesh Singh Thank you for your insightful answer.