试试这个代码。
如果这不是您所需要的，那么也许您可以从我的帖子中获得的是代码应该始终整洁、可读、适当缩进和注释，所有这些都增加了程序的可理解性。
注意：您的图像在转换为灰度时返回几乎相同的黑白图像，因为您的图像是黑白的，很像二值图像。
我还可以推荐 OpenCV (https://opencv.org/)，它是在 BSD 许可证下的，它简单、强大并且可用于 Java - 尽管我记得在 Ubuntu 16.04 上安装它时它是一个 PITA .
import java.io.File;
import java.io.IOException;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
/**
* This class converts images to grayscale color.
*/
public class GrayscaleConverter {
/**
* Creates a new grayscaled BufferedImage object from the given source image
* by averaging each pixels RGB value.
*
* @param inputImageAbsPath the absolute path of the image file, including its name and extension.
* @return a BufferedImage object.
*/
private BufferedImage compute(String inputImageAbsPath) {
System.out.println("... Converting source image to gray scale.");
BufferedImage img = null; // image file
// Read the source image or throw an exception
try {
img = ImageIO.read(new File(inputImageAbsPath));
} catch(Exception e) {
e.printStackTrace();
}
// Get the image width and height dimensions
int width = img.getWidth();
int height = img.getHeight();
// Convert to grayscale by looping over pixels, beginning at top-most left coordinate (0,0)
for (int y = 0; y < height; y++) { // y = rows
for (int x = 0; x < width; x++) { // x = columns
// Get the pixel value at this (x,y) coordinate
int p = img.getRGB(x,y);
// Extract the alpha, R, G, B values from pixel p
int a = (p>>24) & 0xff; // Shift bits and unsign
int r = (p>>16) & 0xff;
int g = (p>>8) & 0xff;
int b = p & 0xff;
// Calculate average color (grayscale it)
int avg = (r+g+b)/3;
// Replace RGB value with avg
p = (a<<24) | (avg<<16) | (avg<<8) | avg;
img.setRGB(x, y, p);
}
}
return img;
}
/**
* Saves the converted grayscale image. This method builds the save path from the provided file name,
* file extension, and absolute path of the folder that you want to save the image in.
*
* @param path the absolute path of the folder that you would like to save the image inside.
* @param imageName the name you would like to save the image with.
* @param imageFileType the image file extension, without the dot (.) preceding the image file type.
* @param image the BufferedImage object returned from the compute method.
*/
private void saveImage(String path, String imageName, String imageFileType, BufferedImage image) {
// Save or throw exception
try {
System.out.println("... Saving grayscale image to "
+ path.concat("\\").concat(imageName).concat(".").concat(imageFileType)); // save path displayed to user
ImageIO.write(image,
imageFileType,
new File(path.concat("\\").concat(imageName).concat(".").concat(imageFileType)));
} catch(Exception e) {
e.printStackTrace();
}
System.out.println("... Image saved.");
}
// Driver
public static void main(String args[]) throws IOException {
/*
* Tested for .png and .jpg files. Both worked successfully.
*/
// Test
System.out.println("Testing GrayscaleConverter.\n");
String input = "*source images absolute file path including name and extension*";
String outputPath = "*absolute path to folder where you will save grayscale image in*";
String outputFileName = "*save image with this name*";
String outputFileType = "*save image with this file extension (no dot (.) e.g. png or jpg)*";
GrayscaleConverter gsc = new GrayscaleConverter();
BufferedImage convertedImage = gsc.compute(input);
gsc.saveImage(outputPath, outputFileName, outputFileType, convertedImage );
System.out.println("\nTest complete.");
}
}
您提供的输入图片：
您的输出图片：
另一个示例输入图像：
另一个示例输出图像：
我用 .png 和 .jpg 图像文件测试了我的程序，它工作正常。祝你好运。