Google Earth engine - Landsat 1985-2020 ecological remote sensing index resi calculation

  This time is to use Landsat Series of images are year by year RSEI analysis , Get images year by year

Spectral time series curve interpolation function
// Linear interpolation is used to interpolate some missing data in the time series spectral curve according to the spectral information before and after its time
// Parameters ：imgcoll Image set type （imagecollection） Need assurance , The sequence of images is arranged according to time , The time of the first image should be the earliest .
  Each image has at least two bands , Except for the band to be interpolated , There should be a time band , by Int type , Represents the time of the image , The unit can be determined by oneself ,
  But the same image set should have a unified time unit , This band should be within the full range of the image NULL, And cannot be located in the first band of the image .
In addition, each image needs to have a “system:time_start” Properties of , It will be transferred to the interpolated image , To facilitate correspondence .
// Parameters ：timeBandNames String type （String）, It represents the first parameter imgcoll The band name of the time band of the image in .
// return ：imgcoll_Interpol Image set type （imagecollection） The result after interpolation is similar to imgcoll The sequence of images is the same .

Code ：

var roi = 
    /* color: #d63000 */
    /* displayProperties: [
      {
        "type": "rectangle"
      }
    ] */
    ee.Geometry.Polygon(
        [[[105.55104505173978, 34.27794089351641],
          [105.55104505173978, 33.5