Java BufferImage图片处理（获取宽高、图片截取、转换灰度图）

news/2024/9/19 7:43:30

Java BufferImage图片处理（获取宽高、截取、转换灰度图）

- 1. 效果图
- 2. 源码
- 参考

这篇博客将介绍如何使用Java读取图片为byte[]数组，或者BufferedImage及互相转换，并进行了转换图片为灰度图，截取部分区域等；

1. 效果图

原始图如下：
在这里插入图片描述

截取部分区域（右下角樱桃）彩色图 VS 截取部分区域并转灰度图：
在这里插入图片描述

2. 源码

package com.ocr.util;import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;/**************************************Class Name: ImageUtils*Description: <图片处理工具类>*@author: Seminar*@since 1.0.0*************************************/
public class ImageUtils {/*** byte[] 转 BufferedImage** @param bytes* @return* @throws IOException*/public static BufferedImage bytesToBufferedImage(byte[] bytes) throws IOException {ByteArrayInputStream in = new ByteArrayInputStream(bytes);  // 将bytes作为输入流BufferedImage image = ImageIO.read(in);     //将in作为输入流，读取图片存入image中，而这里in可以为ByteArrayInputStream();return image;}/*** BufferedImage 转 byte[]** @param image* @return* @throws IOException*/public static byte[] bufferedImageToBytes(BufferedImage image) throws IOException {ByteArrayOutputStream outputStream = new ByteArrayOutputStream();ImageIO.write(image, "jpg", outputStream);return outputStream.toByteArray();}/*** 读取图片为灰度图** @param imagePath 图片绝对路径* @return* @throws IOException*/public static BufferedImage readAsGrayImage(String imagePath) throws IOException {BufferedImage src = ImageIO.read(new File(imagePath));  //BufferedImage 类的图片资源BufferedImage grayImage = new BufferedImage(src.getWidth(), src.getHeight(), BufferedImage.TYPE_BYTE_GRAY);for (int i = 0; i < src.getWidth(); i++) {for (int j = 0; j < src.getHeight(); j++) {int rgb = grayImage.getRGB(i, j);grayImage.setRGB(i, j, rgb);}}return grayImage;}/*** 读取图片后截取** @param imagePath 图片绝对路径* @param width     要截取的图片区域宽度* @param height    要截取的图片区域高度* @return BufferedImage 截取后的图片* @throws IOException*/public static BufferedImage cropImage(String imagePath, int width, int height) throws IOException {BufferedImage src = ImageIO.read(new File(imagePath));  //BufferedImage 类的图片资源BufferedImage crop = src.getSubimage(src.getWidth() - width, src.getHeight() - height, width, height);return crop;}/*** 图片截取并转灰度图** @param src    原始图片* @param width  要截取的图片区域宽度* @param height 要截取的图片区域高度* @return BufferedImage 截取后的图片* @throws IOException*/public static BufferedImage cropImageToGray(BufferedImage src, int width, int height) throws IOException {// 图片截取BufferedImage crop = src.getSubimage(src.getWidth() - width, src.getHeight() - height, width, height);File cropOutputFile = new File("E:\\mat\\mvt\\java-ocr-demo\\images\\crop.jpg");ImageIO.write(crop, "jpg", cropOutputFile);// 图片转灰度图BufferedImage grayImage = new BufferedImage(width, height, BufferedImage.TYPE_BYTE_GRAY);for (int i = 0; i < width; i++) {for (int j = 0; j < height; j++) {int rgb = crop.getRGB(i, j);grayImage.setRGB(i, j, rgb);}}// 保存图片到本地File outputfile = new File("E:\\mat\\mvt\\java-ocr-demo\\images\\crop_gray.jpg");ImageIO.write(grayImage, "jpg", outputfile);return crop;}public static void main(String[] args) throws IOException {String imgPath = "E:\\mat\\mvt\\java-ocr-demo\\images\\yt.jpg";// 读取图片为BufferedImageBufferedImage bufferedImage = ImageIO.read(new File(imgPath));// 读取图片为灰度图BufferedImage gray = readAsGrayImage(imgPath);// 截取图片区域RGBBufferedImage crop = cropImage(imgPath, 240,180);// 截取图片区域灰度图BufferedImage cropGray = cropImageToGray(bufferedImage, 240,180);// BufferedImage转byte[]byte[] bytes = bufferedImageToBytes(bufferedImage);// byte[] 转 BufferedImageBufferedImage bi = bytesToBufferedImage(bytes);}
}