java实现车牌识别代码
时间: 2023-10-14 17:05:42 浏览: 92
车牌识别java代码
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车牌识别是一个涉及到图像处理、机器学习等多个领域的复杂问题,需要综合运用多种算法和技术才能实现。以下是一个简单的基于Java的车牌识别代码示例:
1. 导入所需的Java包:
```java
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
```
2. 读取图片:
```java
BufferedImage image = null;
try {
image = ImageIO.read(new File("car.jpg"));
} catch (IOException e) {
e.printStackTrace();
}
```
3. 图像处理操作,如灰度化、二值化、边缘检测等:
```java
// 灰度化
int width = image.getWidth();
int height = image.getHeight();
for(int i=0; i<height; i++) {
for(int j=0; j<width; j++) {
int rgb = image.getRGB(j, i);
int r = (rgb >> 16) & 0xFF;
int g = (rgb >> 8) & 0xFF;
int b = (rgb >> 0) & 0xFF;
int gray = (int) (0.299 * r + 0.587 * g + 0.114 * b);
image.setRGB(j, i, (gray << 16) | (gray << 8) | gray);
}
}
// 二值化
int threshold = 100;
for(int i=0; i<height; i++) {
for(int j=0; j<width; j++) {
int rgb = image.getRGB(j, i);
int gray = (rgb >> 16) & 0xFF;
if(gray < threshold) {
image.setRGB(j, i, 0xFF000000);
} else {
image.setRGB(j, i, 0xFFFFFFFF);
}
}
}
// 边缘检测
for(int i=1; i<height-1; i++) {
for(int j=1; j<width-1; j++) {
int p1 = (image.getRGB(j-1, i-1) & 0xFF) + (image.getRGB(j, i-1) & 0xFF) + (image.getRGB(j+1, i-1) & 0xFF);
int p2 = (image.getRGB(j-1, i) & 0xFF) + (image.getRGB(j, i) & 0xFF) + (image.getRGB(j+1, i) & 0xFF);
int p3 = (image.getRGB(j-1, i+1) & 0xFF) + (image.getRGB(j, i+1) & 0xFF) + (image.getRGB(j+1, i+1) & 0xFF);
int gx = p1 - p3;
int gy = p2 - p3;
int gray = (int) Math.sqrt(gx * gx + gy * gy);
if(gray > threshold) {
image.setRGB(j, i, 0xFF000000);
} else {
image.setRGB(j, i, 0xFFFFFFFF);
}
}
}
```
4. 车牌定位,可以使用基于轮廓分析、颜色分析、形态学处理等方法:
```java
// 轮廓分析
int minArea = 100;
int maxArea = 10000;
for(int i=1; i<height-1; i++) {
for(int j=1; j<width-1; j++) {
int rgb = image.getRGB(j, i);
if((rgb & 0xFF) == 0) {
// 找到一个黑点,从这个点开始进行轮廓跟踪
List<Point> contour = new ArrayList<Point>();
Point start = new Point(j, i);
Point p = start;
int direction = 0;
do {
contour.add(p);
int x = p.x;
int y = p.y;
int[] dx = {0, 1, 0, -1};
int[] dy = {-1, 0, 1, 0};
int[] dir = {0, 1, 2, 3};
boolean found = false;
for(int k=0; k<4; k++) {
int d = (direction + dir[k]) % 4;
int nx = x + dx[d];
int ny = y + dy[d];
if(nx >= 0 && nx < width && ny >= 0 && ny < height) {
int nrgb = image.getRGB(nx, ny) & 0xFF;
if(nrgb == 0) {
direction = d;
p = new Point(nx, ny);
found = true;
break;
}
}
}
if(!found) {
break;
}
} while(!p.equals(start));
if(contour.size() >= 4 && contour.size() <= 20) {
// 计算轮廓面积
int area = 0;
for(int k=0; k<contour.size(); k++) {
Point p1 = contour.get(k);
Point p2 = contour.get((k+1)%contour.size());
area += p1.x * p2.y - p1.y * p2.x;
}
area = Math.abs(area) / 2;
if(area >= minArea && area <= maxArea) {
// 符合条件的轮廓,标记为红色
for(Point p1 : contour) {
image.setRGB(p1.x, p1.y, 0xFFFF0000);
}
}
}
}
}
}
```
5. 车牌字符分割:
```java
// 字符分割
List<BufferedImage> chars = new ArrayList<BufferedImage>();
int[] points = new int[width];
for(int j=0; j<width; j++) {
int count = 0;
for(int i=0; i<height; i++) {
int rgb = image.getRGB(j, i) & 0xFF;
if(rgb == 0) {
count++;
}
}
points[j] = count;
}
int start = -1;
for(int j=0; j<width; j++) {
if(points[j] > 0 && start == -1) {
start = j;
} else if(points[j] == 0 && start != -1) {
int end = j - 1;
int width = end - start + 1;
int height = image.getHeight();
BufferedImage subimage = image.getSubimage(start, 0, width, height);
chars.add(subimage);
start = -1;
}
}
if(start != -1) {
int end = width - 1;
int width = end - start + 1;
int height = image.getHeight();
BufferedImage subimage = image.getSubimage(start, 0, width, height);
chars.add(subimage);
}
```
6. 对每个字符进行识别,可以使用机器学习算法、模板匹配等方法:
```java
// 字符识别
for(BufferedImage charImage : chars) {
// TODO: 对 charImage 进行字符识别
}
```
以上是一个简单的车牌识别代码示例,实际的车牌识别系统要比这个复杂得多,需要结合实际应用场景和数据进行优化和改进。
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