python 将图像转换为灰度图像

python 版本3.6.5

示例代码：

from PIL import Image
import numpy as np

a = np.array(Image.open("图片路径").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_y**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.sin(vec_az)
dz = np.sin(vec_el)

b = 255*(dx*uni_x+dy*uni_y+dz*uni_z)
b = b.clip(0, 225)

im = Image.fromarray(b.astype('uint8'))

im.save("图片路径")   #保存图片
im.show()

使用图片：

                                                                   

转换后的图像