imageutils.py 文件源码

def logscale_img(img_array,
                 cap=255.0,
                 coeff=1000.0):
    '''
    This scales the image according to the relation:

    logscale_img = np.log(coeff*(img/max(img))+1)/np.log(coeff)

    Taken from the DS9 scaling algorithms page at:

    http://hea-www.harvard.edu/RD/ds9/ref/how.html

    According to that page:

    coeff = 1000.0 works well for optical images
    coeff = 100.0 works well for IR images

    '''

    logscaled_img = np.log(coeff*img_array/np.nanmax(img_array)+1)/np.log(coeff)
    return cap*logscaled_img