Opencv 利用k-平均聚类算法进行减色处理第二步|极客教程

利用 $k-$ 平均聚类算法进行减色处理第二步—-减色处理.

实现上一节提到的算法的第3到5步。

# 选择的颜色
[[182.86730957 156.13246155 180.24510193]
 [156.75152588 123.88993835 137.39085388]
 [227.31060791 199.93135071 209.36465454]
 [ 91.9105835   57.94448471  58.26378632]
 [121.8759613   88.4736557   96.99688721]]

减色处理可以将图像处理成手绘风格。如果 $k=10$ ，则可以在保持一些颜色的同时将图片处理成手绘风格。

现在， $k=5$ 的情况下试着将madara.jpg进行减色处理。

输入 (imori.jpg)	输出(answer_92.jpg)	k=10(answer_92_k10.jpg)	输入2 (madara.jpg)	输出(answer_92_m.jpg)

python实现：

import cv2
import numpy as np
import matplotlib.pyplot as plt
from glob import glob

def k_means(img, Class=5):
    # get shape
    H, W, C = img.shape

    # initiate random seed
    np.random.seed(0)

    # reshape image
    img = np.reshape(img, (H * W, -1))

    # get index randomly
    i = np.random.choice(np.arange(H * W), Class, replace=False)
    Cs = img[i].copy()

    while True:
        # prepare pixel class label
        clss = np.zeros((H * W), dtype=int)

        # each pixel
        for i in range(H * W):
            # get distance from index pixel
            dis = np.sqrt(np.sum((Cs - img[i])**2, axis=1))
            # get argmin distance
            clss[i] = np.argmin(dis)

        # selected pixel values
        Cs_tmp = np.zeros((Class, 3))

        # each class label
        for i in range(Class):
            Cs_tmp[i] = np.mean(img[clss == i], axis=0)

        # if not any change
        if (Cs == Cs_tmp).all():
            break
        else:
            Cs = Cs_tmp.copy()

    # prepare out image
    out = np.zeros((H * W, 3), dtype=np.float32)

    # assign selected pixel values  
    for i in range(Class):
        out[clss == i] = Cs[i]

    print(Cs)

    out = np.clip(out, 0, 255)

    # reshape out image
    out = np.reshape(out, (H, W, 3))
    out = out.astype(np.uint8)

    return out

# read image
img = cv2.imread("imori.jpg").astype(np.float32)

# K-means
out = k_means(img)

cv2.imwrite("out.jpg", out)
cv2.imshow("result", out)
cv2.waitKey(0)