[Python知识库]Python脚本013：Histogram of the image illumination

Author:Xuliu
Time:20211109
Fuction:Histogram of the image illumination,x symbolizes the value of Average_RGB
and y represents the value of Image Numbers

from PIL import Image, ImageStat
import math
import os
import matplotlib.pyplot as plt
import numpy as np
import cv2

def brightness(im_file):
    im = Image.open(im_file)
    stat = ImageStat.Stat(im)
    r, g, b = stat.mean
    return math.sqrt(0.241 * (r ** 2) + 0.691 * (g ** 2) + 0.068 * (b ** 2))


def illumination_averge(directory_name):
    illumination_averge = []
    for filename in os.listdir(directory_name):
        # 用os库读取文件夹内所有图片名称以操作
        # print(filename)
        # img = Image.open(directory_name + "/" + filename)
        im_file = directory_name + "/" + filename
        illumination_averge.append(brightness(im_file))
    return illumination_averge

def draw_hist(directory_name):  
    illumination_averges = illumination_averge(directory_name)
    plt.figure(figsize=(15,5))
    nums,bins,patches = plt.hist(illumination_averges,bins=20,edgecolor='k') #bins:区间个数 ,nums:这个参数是指定每个bin(箱子)分布的数据,对应x轴,pathes
    plt.xlabel("Illumination")
    plt.ylabel("Image Numbers")
    # from IPython import embed
    # embed()
    for num,bin in zip(nums,bins):
        plt.annotate(num,xy=(bin,num),xytext=(bin,num))
    plt.show()



if __name__ == '__main__':
    directory_name = '/home/jy/xl/workstation/Datasets/Car/Cut_Car_Dataset/Car_dataset_Cut'
    draw_hist(directory_name)