我只是在玩同一个主题，这是访问像素的最快方法。我目前知道执行此操作的两种方法：
使用
getRGB()@tskuzzy的答案中所述的BufferedImage 方法。
通过直接使用以下方式访问像素数组：
byte[] pixels = ((DataBufferByte) bufferedImage.getRaster().getDataBuffer()).getData();
如果你要处理大图像并且性能是一个问题，则第一种方法绝对不是可行的方法。该getRGB()方法将alpha，红色，绿色和蓝色的值合并为一个int，然后返回结果，在大多数情况下，你将进行相反操作以将这些值取回。
第二种方法将直接为每个像素返回红色，绿色和蓝色值，如果有alpha通道，它将添加alpha值。使用此方法在计算指标方面比较困难，但是比第一种方法要快得多。
在我的应用程序中，通过从第一种方法切换到第二种方法，我能够将像素处理时间减少90％以上！
这是我为比较两种方法而设置的比较：
import java.awt.image.BufferedImage;import java.awt.image.DataBufferByte;import java.io.IOException;import javax.imageio.ImageIO;public class PerformanceTest { public static void main(String[] args) throws IOException { BufferedImage hugeImage = ImageIO.read(PerformanceTest.class.getResource("12000x12000.jpg")); System.out.println("Testing convertTo2DUsingGetRGB:"); for (int i = 0; i < 10; i++) { long startTime = System.nanoTime(); int[][] result = convertTo2DUsingGetRGB(hugeImage); long endTime = System.nanoTime(); System.out.println(String.format("%-2d: %s", (i + 1), toString(endTime - startTime))); } System.out.println(""); System.out.println("Testing convertTo2DWithoutUsingGetRGB:"); for (int i = 0; i < 10; i++) { long startTime = System.nanoTime(); int[][] result = convertTo2DWithoutUsingGetRGB(hugeImage); long endTime = System.nanoTime(); System.out.println(String.format("%-2d: %s", (i + 1), toString(endTime - startTime))); } } private static int[][] convertTo2DUsingGetRGB(BufferedImage image) { int width = image.getWidth(); int height = image.getHeight(); int[][] result = new int[height][width]; for (int row = 0; row < height; row++) { for (int col = 0; col < width; col++) { result[row][col] = image.getRGB(col, row); } } return result; } private static int[][] convertTo2DWithoutUsingGetRGB(BufferedImage image) { final byte[] pixels = ((DataBufferByte) image.getRaster().getDataBuffer()).getData(); final int width = image.getWidth(); final int height = image.getHeight(); final boolean hasAlphaChannel = image.getAlphaRaster() != null; int[][] result = new int[height][width]; if (hasAlphaChannel) { final int pixelLength = 4; for (int pixel = 0, row = 0, col = 0; pixel + 3 < pixels.length; pixel += pixelLength) { int argb = 0; argb += (((int) pixels[pixel] & 0xff) << 24); // alpha argb += ((int) pixels[pixel + 1] & 0xff); // blue argb += (((int) pixels[pixel + 2] & 0xff) << 8); // green argb += (((int) pixels[pixel + 3] & 0xff) << 16); // red result[row][col] = argb; col++; if (col == width) { col = 0; row++; } } } else { final int pixelLength = 3; for (int pixel = 0, row = 0, col = 0; pixel + 2 < pixels.length; pixel += pixelLength) { int argb = 0; argb += -16777216; // 255 alpha argb += ((int) pixels[pixel] & 0xff); // blue argb += (((int) pixels[pixel + 1] & 0xff) << 8); // green argb += (((int) pixels[pixel + 2] & 0xff) << 16); // red result[row][col] = argb; col++; if (col == width) { col = 0; row++; } } } return result; } private static String toString(long nanoSecs) { int minutes = (int) (nanoSecs / 60000000000.0); int seconds = (int) (nanoSecs / 1000000000.0) - (minutes * 60); int millisecs = (int) ( ((nanoSecs / 1000000000.0) - (seconds + minutes * 60)) * 1000); if (minutes == 0 && seconds == 0) return millisecs + "ms"; else if (minutes == 0 && millisecs == 0) return seconds + "s"; else if (seconds == 0 && millisecs == 0) return minutes + "min"; else if (minutes == 0) return seconds + "s " + millisecs + "ms"; else if (seconds == 0) return minutes + "min " + millisecs + "ms"; else if (millisecs == 0) return minutes + "min " + seconds + "s"; return minutes + "min " + seconds + "s " + millisecs + "ms"; }}你能猜出输出吗？;）
Testing convertTo2DUsingGetRGB:1 : 16s 911ms2 : 16s 730ms3 : 16s 512ms4 : 16s 476ms5 : 16s 503ms6 : 16s 683ms7 : 16s 477ms8 : 16s 373ms9 : 16s 367ms10: 16s 446msTesting convertTo2DWithoutUsingGetRGB:1 : 1s 487ms2 : 1s 940ms3 : 1s 785ms4 : 1s 848ms5 : 1s 624ms6 : 2s 13ms7 : 1s 968ms8 : 1s 864ms9 : 1s 673ms10: 2s 86msBUILD SUCCESSFUL (total time: 3 minutes 10 seconds)
