编辑：更新了代码，下面的代码现在可以正确地围绕多个形状绘制矩形，但仍然存在一个小问题，即有时会在一个形状上创建多个矩形。
我有 2 个图像，我将它们逐像素进行比较，并且我希望我的程序在差异区域周围创建矩形（具有多个差异实例的多个矩形）。到目前为止，我设法用一个矩形来做到这一点，所以如果我有多个“实例”，它们都会在一个大矩形中。现在我试图让程序创建多个矩形，但遇到了 IndexOutOfBoundsException。
程序本身覆盖与不透明度进行比较的 2 个图像，并将生成的覆盖图像与矩形一起输出到新文件中。被比较的两个图像具有一致的相等宽度和高度。
我在代码中将要绘制的矩形称为“区域”。 在比较过程中，区域列表会不断更新。
我问自己的第一个问题是，什么时候差异点（像素差异）属于一个区域？ 我的尝试是定义一个“容差”，因此只要被比较的像素在最后发现的差异点的容差范围内，它就属于同一区域。我很快意识到，当我的图像上有一个巨大的 U 形形状时，这不起作用，并且顶点之间的距离足够远，不在公差范围内。现在我有点陷入困境，因为我觉得我走错了路。
下面是我到目前为止的代码：
private void compareImages() throws IOException{
BufferedImage img1;
BufferedImage img2;
try {
img1 = ImageIO.read(new File(path_to_img1));
img2 = ImageIO.read(new File(path_to_img2));
} catch (Throwable e) {
System.out.println("Unable to load the Images!");
return;
}
BufferedImage dest = new BufferedImage(img1.getWidth(), img1.getHeight(), BufferedImage.TYPE_INT_ARGB);
Graphics2D gfx = dest.createGraphics();
gfx.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.65f));
//Compare Images pixel by pixel
int sX = 9999; //Start X
int sY = 9999; //Start Y
int eX = 0; //End X
int eY = 0; //End Y
boolean isDrawable = false;
boolean loadedRegion = false;
List<Rectangle> regions = new ArrayList<>();
List<Rectangle> check_regions = new ArrayList<>();
Rectangle tmp_comparison;
int regionID = 0;
int tolerance = 25;
for (int i = 0; i < img1.getHeight(); i++) {
for (int j = 0; j < img1.getWidth(); j++) {
loadedRegion = false;
regionID = 0;
sX = 9999;
sY = 9999;
eX = 0;
eY = 0;
if ( img1.getRGB(j, i) != img2.getRGB(j, i) ){
isDrawable = true;
if (regions.size() != 0){
//Attempting to locate a matching existing Region
tmp_comparison = new Rectangle(j, i, 1, 1);
for (int trID = 0; trID<regions.size(); trID++){
if (tmp_comparison.intersects(check_regions.get(trID).getBounds()) == true) {
// Region found
sX = (int) regions.get(trID).getX();
sY = (int) regions.get(trID).getY();
eX = (int) regions.get(trID).getWidth();
eY = (int) regions.get(trID).getHeight();
regionID = trID;
loadedRegion = true;
break;
}
}
}
//Update Region Dimension
if (j<sX){
sX = j;
}
if (j>eX){
eX = j;
}
if (i<sY){
sY = i;
}
if (i>eY){
eY = i;
}
if (regions.size() == 0 || loadedRegion == false){
regions.add(new Rectangle(sX, sY, eX, eY));
check_regions.add(new Rectangle(sX-tolerance, sY-tolerance, eX-sX+(tolerance*2), eY-sY+(tolerance*2)));
} else {
regions.set(regionID, new Rectangle(sX, sY, eX, eY));
check_regions.set(regionID, new Rectangle(sX-tolerance, sY-tolerance, eX-sX+(tolerance*2), eY-sY+(tolerance*2)));
}
}
}
}
// If there are any differences, draw the Regions
// Regions are 10px bigger in all directions as compared to the actual rectangles of difference
if (isDrawable == true){
gfx.setPaint(Color.red);
for (int i = 0; i<regions.size(); i++) {
int dsX = 0;
int dsY = 0;
int deX = 0;
int deY = 0;
sX = (int) regions.get(i).getX();
sY = (int) regions.get(i).getY();
eX = (int) regions.get(i).getWidth();
eY = (int) regions.get(i).getHeight();
if (sX>=10){dsX = sX-10;}
if (eX<=img1.getWidth()-10){deX = eX-sX+20;}
if (sY>=10){dsY = sY-10;}
if (eY<=img1.getHeight()-10){deY = eY-sY+20;}
gfx.draw(new Rectangle2D.Double(dsX, dsY, deX, deY));
}
}
gfx.drawImage(img1, 0, 0, null);
gfx.drawImage(img2, 0, 0, null);
gfx.dispose();
File out = new File("C:\\output.png");
ImageIO.write(dest, "PNG", out);
}
下面的代码围绕正在比较的图像中发现的所有差异创建一个大矩形。
private void oneRectangle() throws IOException{
BufferedImage img1;
BufferedImage img2;
try {
img1 = ImageIO.read(new File(path_to_img1));
img2 = ImageIO.read(new File(path_to_img2));
} catch (Throwable e) {
System.out.println("Unable to load the Images!");
return;
}
BufferedImage dest = new BufferedImage(img1.getWidth(), img1.getHeight(), BufferedImage.TYPE_INT_ARGB);
Graphics2D gfx = dest.createGraphics();
gfx.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.65f));
//Compare Images pixel by pixel
boolean isDrawable = false;
int sX = 9999;
int sY = 9999;
int eX = 0;
int eY = 0;
for (int i = 0; i < img1.getHeight(); i++) {
for (int j = 0; j < img1.getWidth(); j++) {
if ( img1.getRGB(j, i) != img2.getRGB(j, i) ){
isDrawable = true;
if (j<sX){
sX = j;
}
if (j>eX){
eX = j;
}
if (i<sY){
sY = i;
}
if (i>eY){
eY = i;
}
}
}
}
// Draw rectangle if there are any differences
if (isDrawable == true){
gfx.setPaint(Color.red);
int dsX = 0;
int dsY = 0;
int deX = 0;
int deY = 0;
if (sX>=10){dsX = sX-10;}
if (eX<=img1.getWidth()-10){deX = eX-sX+20;}
if (sY>=10){dsY = sY-10;}
if (eY<=img1.getHeight()-10){deY = eY-sY+20;}
gfx.fill(new Rectangle2D.Double(dsX, dsY, deX, deY));
}
gfx.drawImage(img1, 0, 0, null);
gfx.drawImage(img2, 0, 0, null);
gfx.dispose();
File out = new File("C:\\output.png");
ImageIO.write(dest, "PNG", out);
}
感谢您提供示例代码。我发现多个矩形的问题取决于如何发现差异。基本上，最初会有两个点不够接近而无法加入，但在某个时刻，其中一个盒子会变得足够大，以至于它们可以加入。我发现管理此问题的最简单方法是清理最后的所有相交边界。我还发现，通过水平扫描而不是垂直扫描，我得到的这些伪像更少，因为我正在比较人类文本。
//Reduce intersecting rectangles
boolean fixed = true;
while(fixed) {
fixed = false;
for(int i = 0; i < regions.size(); i++){
for(int j = i+1; j < regions.size(); j++){
if(regions.get(i).intersects(regions.get(j))) {
regions.get(j).add(regions.get(i));
regions.remove(i--);
fixed = true;
break;
}
}
}
}
我修改了原始代码以简化一点。
public static void compareImages() throws IOException {
BufferedImage img1 = ImageIO.read(new File(path_to_img1));
BufferedImage img2 = ImageIO.read(new File(path_to_img2));
BufferedImage dest = new BufferedImage(img1.getWidth(), img1.getHeight(), BufferedImage.TYPE_INT_ARGB);
Graphics2D gfx = dest.createGraphics();
try {
gfx.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.65f));
//Compare Images pixel by pixel
List<Rectangle> regions = new ArrayList<>();
int tolerance = 20;
for (int j = 0; j < img1.getWidth(); j++) {
pixelLoop: for (int i = 0; i < img1.getHeight(); i++) {
int img1rgb = img1.getRGB(j, i);
int img2rgb = img2.getRGB(j, i);
if(img1rgb != img2rgb) {
for(Rectangle region : regions){
//Attempting to locate a matching existing Region
Rectangle tmp_comparison = new Rectangle(j-tolerance, i-tolerance, 2*tolerance, 2*tolerance);
if (tmp_comparison.intersects(region)) {
region.add(new Rectangle(j, i, 1, 1));
continue pixelLoop;
}
}
regions.add(new Rectangle(j, i, 1, 1));
}
}
}
//Reduce intersecting rectangles
boolean fixed = true;
while(fixed) {
fixed = false;
for(int i = 0; i < regions.size(); i++){
for(int j = i+1; j < regions.size(); j++){
if(regions.get(i).intersects(regions.get(j))) {
regions.get(j).add(regions.get(i));
regions.remove(i--);
fixed = true;
break;
}
}
}
}
gfx.drawImage(img1, 0, 0, null);
gfx.drawImage(img2, 0, 0, null);
gfx.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 1f));
gfx.setPaint(Color.red);
if(!regions.isEmpty()) {
// If there are any differences, draw the Regions
// Regions are 10px bigger in all directions as compared to the actual rectangles of difference
for (Rectangle region : regions) {
region.add(new Rectangle2D.Double(region.getX()-10, region.getY()-10, region.getWidth()+20, region.getHeight()+20));
gfx.draw(new Rectangle2D.Double(region.getX() >= 0 ? region.getX() : 0, region.getY() >= 0 ? region.getY() : 0, Math.min(img1.getWidth(), region.getWidth()), Math.min(img1.getHeight(), region.getHeight())));
}
File out = new File("C:\\output.png");
ImageIO.write(dest, "PNG", out);
}
} finally {
gfx.dispose();
}
}