// We use the filtered image to find the dark stain.
let { KMedians.fg = fg; KMedians.median_bg = median_bg; KMedians.median_fg = median_fg; KMedians.d_fg = d_fg } = kmediansResult
let darkStain = d_fg.Cmp(median_bg * config.darkStainLevel, CvEnum.CmpType.GreaterThan)
// We use the filtered image to find the dark stain.
let { KMedians.fg = fg; KMedians.median_bg = median_bg; KMedians.median_fg = median_fg; KMedians.d_fg = d_fg } = kmediansResult
let darkStain = d_fg.Cmp(median_bg * config.darkStainLevel, CvEnum.CmpType.GreaterThan)