遥感影像线性插值（基于GEE平台）

var geometry = ee.Geometry.Polygon([[
  [82.60642647743225, 27.16350437805251],
  [82.60984897613525, 27.1618529901377],
  [82.61088967323303, 27.163695288375266],
  [82.60757446289062, 27.16517483230927]
]]); 
Map.addLayer(geometry, {color: 'red'}, 'Farm')
Map.centerObject(geometry)
var s2 = ee.ImageCollection("COPERNICUS/S2_SR");
var filtered = s2
  .filter(ee.Filter.date('2019-01-01', '2020-01-01'))
  .filter(ee.Filter.lt('CLOUDY_PIXEL_PERCENTAGE', 30))
  .filter(ee.Filter.bounds(geometry))
// 数据去云处理
function maskCloudAndShadowsSR(image) {
  var cloudProb = image.select('MSK_CLDPRB');
  var snowProb = image.select('MSK_SNWPRB');
  var cloud = cloudProb.lt(5);
  var snow = snowProb.lt(5);
  var scl = image.select('SCL'); 
  var shadow = scl.eq(3); // 3 = cloud shadow
  var cirrus = scl.eq(10); // 10 = cirrus
  var mask = (cloud.and(snow)).and(cirrus.neq(1)).and(shadow.neq(1));
  return image.updateMask(mask).divide(10000)
      .select("B.*")
      .copyProperties(image, ["system:time_start"]);
}
var filtered = filtered.map(maskCloudAndShadowsSR)

var filtered = filtered.map(function(image) {
  var timeImage = image.metadata('system:time_start').rename('timestamp')
  var timeImageMasked = timeImage.updateMask(image.mask().select(0))
  return image.addBands(timeImageMasked)
})

//定义两个join，一个是距离目标影像30天范围内，并且是日期在目标影像之前，
//另一个是在目标影像之后的
var days = 30
var millis = ee.Number(days).multiply(1000*60*60*24)
var maxDiffFilter = ee.Filter.maxDifference({
  difference: millis,
  leftField: 'system:time_start',
  rightField: 'system:time_start'
})
var lessEqFilter = ee.Filter.lessThanOrEquals({
  leftField: 'system:time_start',
  rightField: 'system:time_start'
})
var greaterEqFilter = ee.Filter.greaterThanOrEquals({
  leftField: 'system:time_start',
  rightField: 'system:time_start'
})

var filter1 = ee.Filter.and(maxDiffFilter, lessEqFilter)
 
var join1 = ee.Join.saveAll({
  matchesKey: 'after',
  ordering: 'system:time_start',
  ascending: false})
   
var join1Result = join1.apply({
  primary: filtered,
  secondary: filtered,
  condition: filter1
})
var filter2 = ee.Filter.and(maxDiffFilter, greaterEqFilter)
 
var join2 = ee.Join.saveAll({
  matchesKey: 'before',
  ordering: 'system:time_start',
  ascending: true})
   
var join2Result = join2.apply({
  primary: join1Result,
  secondary: join1Result,
  condition: filter2
})

var interpolateImages = function(image) {
  var image = ee.Image(image)
  // 把匹配的数据合成一个影像
  var beforeImages = ee.List(image.get('before'))
  var beforeMosaic = ee.ImageCollection.fromImages(beforeImages).mosaic()
  var afterImages = ee.List(image.get('after'))
  var afterMosaic = ee.ImageCollection.fromImages(afterImages).mosaic()

  var t1 = beforeMosaic.select('timestamp').rename('t1')
  var t2 = afterMosaic.select('timestamp').rename('t2')
  var t = image.metadata('system:time_start').rename('t')
  var timeImage = ee.Image.cat([t1, t2, t])
  var timeRatio = timeImage.expression('(t - t1) / (t2 - t1)', {
    't': timeImage.select('t'),
    't1': timeImage.select('t1'),
    't2': timeImage.select('t2'),
  })
  // 计算插值数据
  var interpolated = beforeMosaic
    .add((afterMosaic.subtract(beforeMosaic).multiply(timeRatio)))
  var result = image.unmask(interpolated)
  return result.copyProperties(image, ['system:time_start'])
}

var interpolatedCol = ee.ImageCollection(
  join2Result.map(interpolateImages
  
function addNDVI(image) {
  var ndvi = image.normalizedDifference(['B8', 'B4']).rename('ndvi');
  return image.addBands(ndvi);
}

var ndviVis = {min:0, max: 0.9,  palette: [
    'FFFFFF', 'CE7E45', 'DF923D', 'F1B555', 'FCD163', '99B718', '74A901',
    '66A000', '529400', '3E8601', '207401', '056201', '004C00', '023B01',
    '012E01', '011D01', '011301'
  ]}

var visualizeImage = function(image) {
  return image.select('ndvi').visualize(ndviVis).clip(geometry)
}

var visCollectionOriginal = filtered
  .map(addNDVI)
  .map(visualizeImage)
var visCollectionInterpolated = interpolatedCol
  .map(addNDVI)
  .map(visualizeImage)

var videoArgs = {
  dimensions: 400,
  region: geometry,
  framesPerSecond: 1,
  crs: 'EPSG:3857',
};

print('Original NDVI Images', visCollectionOriginal.getVideoThumbURL(videoArgs))
print('Gap Filled NDVI Images', visCollectionInterpolated.getVideoThumbURL(videoArgs))