from PIL import Image
import numpy as np 

a = np.asarray(Image.open('/home/vapor/图片/兵长.jpg').convert('L')).astype('float')

depth = 10
grad = np.gradient(a)
grad_x, grad_y = grad
grad_x=grad_x*depth/100.
grad_y=grad_y*depth/100.

A = np.sqrt(grad_x**2+grad_y**2+1.)
uni_x = grad_x/A
uni_y = grad_y/A
uni_z = 1./A

vec_el = np.pi/2.2
vec_az = np.pi/4.
dx = np.cos(vec_el)*np.cos(vec_az)
dy = np.cos(vec_el)*np.cos(vec_az)
dz = np.sin(vec_el)

b = 255*(dx*uni_x +dy*uni_y +dz*uni_z)
b = b.clip(0,255)

im = Image.fromarray(b.astype('uint8'))
im.save('/home/vapor/图片/兵长.jpg')