使用numpy和PIL进行简单的图像处理方法

from PIL import Image
import numpy as np
# 反相
# a = np.array(Image.open("test.jpg"))
# b = [255, 255, 255] - a
# 灰度，反相
# a = np.array(Image.open("test.jpg").convert('L'))
# b = 255 - a
# 灰度，颜色变谈
# a = np.array(Image.open("test.jpg").convert('L'))
# b = (100/255)*a + 150 # 区间压缩再增加
# 灰度，颜色加重
# a = np.array(Image.open("test.jpg").convert('L'))
# b = 255 * (a/255)**2 # 像素平方
# 转手绘
a = np.array(Image.open('test.jpg').convert('L')).astype('float')
depth = 10.      # (0-100)
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.
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     # 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
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

b = 255*(dx*uni_x + dy*uni_y + dz*uni_z)  #光源归一化
b = b.clip(0,255)
im = Image.fromarray(b.astype("uint8"))
im.save("./result.jpg")