图像的手绘效果1

题目来源：Python数据分析与展示

授课老师： 嵩天

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原图片

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手绘效果后的图片

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代码

import numpy as np
from PIL import Image
#读取图片并对图片进行灰度化后存储到numpy数组中
a = np.array(Image.open("D:\\pyCourse\\ff.jpg").convert('L')).astype('float')
depth = 10
#计算梯度
grad= np.gradient(a)
grad_x, grad_y = grad
print(grad_x,grad_y)
grad_x = grad_x * depth/100
grad_y = grad_y * depth/100
#梯度的归一化
A = np.sqrt(grad_x**2 + grad_y**2 + 1.)
uni_x = grad_x/A
uni_y = grad_y/A
uni_z = 1./A
#用来计算三维坐标系中x,y,z的投影
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(0,255)
im = Image.fromarray(b.astype('uint8'))
im.save("f4_5.jpg")