filtlib.py 文件源码

def median_fltr_skimage(dem, radius=3, erode=1, origmask=False):
    """
    Older skimage.filter.median_filter

    This smooths, removes noise and fills in nodata areas with median of valid pixels!  Effectively an inpainting routine
    """
    #Note, ndimage doesn't properly handle ma - convert to nan
    dem = malib.checkma(dem)
    dem = dem.astype(np.float64)
    #Mask islands
    if erode > 0:
        print("Eroding islands smaller than %s pixels" % (erode * 2)) 
        dem = malib.mask_islands(dem, iterations=erode)
    print("Applying median filter with radius %s" % radius) 
    #Note: this funcitonality was present in scikit-image 0.9.3
    import skimage.filter
    dem_filt_med = skimage.filter.median_filter(dem, radius, mask=~dem.mask)
    #Starting in version 0.10.0, this is the new filter
    #This is the new filter, but only supports uint8 or unit16
    #import skimage.filters
    #import skimage.morphology 
    #dem_filt_med = skimage.filters.rank.median(dem, disk(radius), mask=~dem.mask)
    #dem_filt_med = skimage.filters.median(dem, skimage.morphology.disk(radius), mask=~dem.mask)
    #Now mask all nans
    #skimage assigns the minimum value as nodata
    #CHECK THIS, seems pretty hacky
    #Also, looks like some valid values are masked at this stage, even though they should be above min
    ndv = np.min(dem_filt_med)
    #ndv = dem_filt_med.min() + 0.001
    out = np.ma.masked_less_equal(dem_filt_med, ndv)
    #Should probably replace the ndv with original ndv
    out.set_fill_value(dem.fill_value)
    if origmask:
        print("Applying original mask")
        #Allow filling of interior holes, but use original outer edge
        #maskfill = malib.maskfill(dem, iterations=radius)
        maskfill = malib.maskfill(dem)
        #dem_filt_gauss = np.ma.array(dem_filt_gauss, mask=dem.mask, fill_value=dem.fill_value)
        out = np.ma.array(out, mask=maskfill, fill_value=dem.fill_value)
    return out