Python彩色图片转手绘风格

from PIL import Image
# 图像的手绘
"""黑白风格
   边界的位置比较重
   相同或相近色彩趋近于白色
   咯有光源效果
"""
# 读取彩色图片并转化为np数组
a = np.array(Image.open(r'114362.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_ez = np.pi/4.
dx = np.cos(vec_el)*np.cos(vec_ez)
dy = np.cos(vec_el)*np.sin(vec_ez)
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'))
# 保存转化后的图片
im.save('ceshi.jpg')

原彩色图片：
转化后图片：