#e17.1HandDrawPic.py

from PIL import Image

import numpy as np

vec_el = np.pi/2.2 # 光源的俯视角度，弧度值

vec_az = np.pi/4. # 光源的方位角度，弧度值

depth = 10. # (0-100)

im = Image.open('C:\\Users\\Thinkpad\\Desktop\\11.jpg').convert('L')

a = np.asarray(im).astype('float')

grad = np.gradient(a) #取图像灰度的梯度值

grad_x, grad_y = grad #分别取横纵图像梯度值

grad_x = grad_x*depth/100.

grad_y = grad_y*depth/100.

dx = np.cos(vec_el)*np.cos(vec_az) #光源对x 轴的影响

dy = np.cos(vec_el)*np.sin(vec_az) #光源对y 轴的影响

dz = np.sin(vec_el) #光源对z 轴的影响

A = np.sqrt(grad_x**2 + grad_y**2 + 1.)

uni_x = grad_x/A

uni_y = grad_y/A

uni_z = 1./A

a2 = 255*(dx*uni_x + dy*uni_y + dz*uni_z) #光源归一化

a2 = a2.clip(0,255)

im2 = Image.fromarray(a2.astype('uint8')) #重构图像

im2.save('C:\\Users\\Thinkpad\\Desktop\\12.jpg')