Untitled

// =====================  normalization function ============================================================================//
var region = geometry
var scale = image_scale
function normalization(image,region,scale){
var mean_std = image.reduceRegion({
  reducer: ee.Reducer.mean()
            .combine(ee.Reducer.stdDev(),null, true),
  geometry: region,
  scale: scale,
  maxPixels: 10e9,
  // tileScale: 16
}); 
// use unit scale to normalize the pixel values
var unitScale = ee.ImageCollection.fromImages(
  image.bandNames().map(function(name){
    name = ee.String(name);
    var band = image.select(name);
    var mean=ee.Number(mean_std.get(name.cat('_mean')));
    var std=ee.Number(mean_std.get(name.cat('_stdDev')));
    var max=mean.add(std.multiply(3))
    var min=mean.subtract(std.multiply(3))
    var band1=ee.Image(min).multiply(band.lt(min)).add(ee.Image(max).multiply(band.gt(max)))
                        .add(band.multiply(ee.Image(1).subtract(band.lt(min)).subtract(band.gt(max))))
    var result_band=band1.subtract(min).divide(max.subtract(min));
    return result_band;
})).toBands().rename(image.bandNames());
  return unitScale
        // .multiply(100)
  ;
}
function normalization_100(image,region,scale){
var mean_std = image.reduceRegion({
  reducer: ee.Reducer.mean()
            .combine(ee.Reducer.stdDev(),null, true),
  geometry: region,
  scale: scale,
  maxPixels: 10e9,
  // tileScale: 16
}); 
// use unit scale to normalize the pixel values
var unitScale = ee.ImageCollection.fromImages(
  image.bandNames().map(function(name){
    name = ee.String(name);
    var band = image.select(name);
    var mean=ee.Number(mean_std.get(name.cat('_mean')));
    var std=ee.Number(mean_std.get(name.cat('_stdDev')));
    var max=mean.add(std.multiply(3))
    var min=mean.subtract(std.multiply(3))
    var band1=ee.Image(min).multiply(band.lt(min)).add(ee.Image(max).multiply(band.gt(max)))
                        .add(band.multiply(ee.Image(1).subtract(band.lt(min)).subtract(band.gt(max))))
    var result_band=band1.subtract(min).divide(max.subtract(min));
    return result_band;
})).toBands().rename(image.bandNames());
  return unitScale
        .multiply(100)
  ;
}


// Normalize BI and AVI
var BI = normalization_100(bsi,region, scale)
var AVI = normalization_100(avi,region, scale)


// Map.addLayer(AVI, imageVisParam5, 'AVI_Nom')
// Map.addLayer(BI, imageVisParam6, 'BI_Nom', 0)

//  

//