将图片转变成手绘图

from PIL import Image
import numpy as np
im=np.array(Image.open("D:/11.jpg").convert('L')).astype("float")
grad=np.gradient(im)
grad_x,grad_y=grad
depth=20#范围在0-100
grad_x=grad_x*depth/100
grad_y=grad_y*depth/100
A=np.sqrt(grad_x**2+grad_y**2+1.)
uin_x=grad_x/A
uin_y=grad_y/A
uin_z=1./A

el=np.pi/2.2
az=1
dx=np.cos(el)*np.cos(az)
dy=np.cos(el)*np.sin(az)
dz=np.sin(el)
b=255*(dx*uin_x+dy*uin_y+dz*uin_z)
b=b.clip(0,255)

im=Image.fromarray(b.astype('uint8'))
im.save("D://2.jpg")