[英]gray-scale image to matrix and matrix to gray-scale image
我正在嘗試從灰度圖像獲取2D矩陣並對其進行修改,然后返回到灰度圖像。
但是,當嘗試將圖像轉換為矩陣時,像素返回黑色值。
如何找到該問題的解決方案?
您可以在代碼下方找到圖片
Java代碼:
public class MyImageProcessing {
private SampleModel sampleModel;
public int[][] compute(File file)
{
try
{
BufferedImage img= ImageIO.read(file);
Raster raster=img.getData();
sampleModel = raster.getSampleModel();
int w=raster.getWidth(),h=raster.getHeight();
int pixels[][]=new int[w][h];
for (int x=0;x<w;x++)
{
for(int y=0;y<h;y++)
{
pixels[x][y]=raster.getSample(x,y,0);
}
}
return pixels;
}
catch (Exception e)
{
e.printStackTrace();
}
return null;
}
public void getImage(int pixels[][])
{
int w=pixels.length;
int h=pixels[0].length;
WritableRaster raster= Raster.createWritableRaster(sampleModel, new Point(0,0));
for(int i=0;i<w;i++)
{
for(int j=0;j<h;j++)
{
raster.setSample(i,j,0,pixels[i][j]);
}
}
BufferedImage image=new BufferedImage(w,h,BufferedImage.TYPE_BYTE_GRAY);
image.setData(raster);
File output=new File("C:\\Users\\salam\\Pictures\\3.png");
try {
ImageIO.write(image,"png",output);
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
原始圖片:
從矩陣檢索的圖像:
試試這個代碼。
如果不是您所需要的,那么也許您可以從我的文章中刪除的是,代碼應始終保持整潔,可讀,適當縮進和注釋,所有這些都增加了程序的可理解性。
注意:轉換為灰度圖像后,圖像幾乎返回相同的黑白圖像,因為圖像是黑白圖像,很像二進制圖像。
我還可以建議使用BSD許可下的OpenCV ( https://opencv.org/ ),它簡單,強大並且可用於Java-盡管我記得在Ubuntu 16.04上安裝它時是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.");
}
}
我同時使用.png和.jpg圖像文件測試了程序,並且可以正常工作。 祝好運。
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