图片直方图

复制from PIL import Image
import numpy as np

# 打开图片并转为 RGB 模式
img = Image.open("photo.jpg").convert("RGB")
pixels = np.array(img)

# 计算 RGB 各通道直方图（256 bins）
hist_r, _ = np.histogram(pixels[:,:,0], bins=256, range=(0,255))
hist_g, _ = np.histogram(pixels[:,:,1], bins=256, range=(0,255))
hist_b, _ = np.histogram(pixels[:,:,2], bins=256, range=(0,255))

# 亮度直方图：加权灰度公式 Y = 0.299R + 0.587G + 0.114B
luminance = np.dot(pixels[...,:3], [0.299, 0.587, 0.114]).astype(np.uint8)
hist_lum, _ = np.histogram(luminance, bins=256, range=(0,255))

print("R 直方图（前10个bin）:", hist_r[:10])
print("亮度直方图（前10个bin）:", hist_lum[:10])

复制package main

import (
	"fmt"
	"image"
	_ "image/jpeg"
	"os"
)

func main() {
	f, _ := os.Open("photo.jpg")
	defer f.Close()
	img, _, _ := image.Decode(f)
	bounds := img.Bounds()

	var histR, histG, histB, histL [256]int
	for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
		for x := bounds.Min.X; x < bounds.Max.X; x++ {
			r, g, b, _ := img.At(x, y).RGBA()
			r8, g8, b8 := r>>8, g>>8, b>>8
			histR[r8]++
			histG[g8]++
			histB[b8]++
			// 亮度：0.299R + 0.587G + 0.114B
			lum := uint8((299*uint32(r8) + 587*uint32(g8) + 114*uint32(b8)) / 1000)
			histL[lum]++
		}
	}
	fmt.Println("R直方图前10个bin:", histR[:10])
	fmt.Println("亮度直方图前10个bin:", histL[:10])
}

复制// 浏览器端：使用 Canvas API 计算直方图
const img = new Image();
img.src = 'photo.jpg';
img.onload = () => {
  const canvas = document.createElement('canvas');
  const ctx = canvas.getContext('2d');
  canvas.width = img.width;
  canvas.height = img.height;
  ctx.drawImage(img, 0, 0);
  
  const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
  const data = imageData.data;
  
  const histR = new Uint32Array(256);
  const histG = new Uint32Array(256);
  const histB = new Uint32Array(256);
  const histL = new Uint32Array(256);
  
  for (let i = 0; i < data.length; i += 4) {
    const r = data[i], g = data[i+1], b = data[i+2];
    histR[r]++;
    histG[g]++;
    histB[b]++;
    // 亮度：0.299R + 0.587G + 0.114B
    const lum = Math.round(0.299*r + 0.587*g + 0.114*b);
    histL[lum]++;
  }
  
  console.log('R直方图前10个bin:', histR.slice(0, 10));
  console.log('亮度直方图前10个bin:', histL.slice(0, 10));
};