图像卷积代码无法正确显示图像？

所以这是交易：我尝试简化（对用户）如何执行卷积 . 我尝试使用它来运行Sobel滤镜，当我尝试显示图像时（通过jfram和图像图标），图像图标不会弹出，它只是一个大的灰色方块 .

jframe / imageicon完美运行，直到我试图让它显示此过滤器结果的输出 .

float[][] sobel = { { -1, 0, 1},
                   { -2, 0, 2},
                   {-1, 0, 1} };
someObject test = new someObject(filepath);
test.convolutionFilter(sobel);

public BufferedImage convolutionFilter(float[][] filter) {
    int columns = filter.length;
    int  rows= filter[0].length;
    float numTemp;
    float[] filter1D = new float[columns*rows];
    for (int j = 0; j<rows; j++) {
        for (int i= 0; i< columns; i++ ) {
            numTemp = filter[j][i];
            System.out.print(numTemp + " ");
            filter1D[j*columns + i] = numTemp;
        }
    }


    Kernel kern = new Kernel(rows, columns, filter1D);
    ConvolveOp op = new ConvolveOp(kern);

    BufferedImage temp = new BufferedImage(processedImage.getWidth(), processedImage.getHeight(), BufferedImage.TYPE_INT_ARGB); 
    op.filter(processedImage, temp);
    processedImage = temp;
    return processedImage;

}

CODE HAS BEEN UPDATED

如果我执行以下操作，我的gui将显示一个没有图像的平面灰色框 . 如果我执行一个命令而不执行另一个命令，则图像将完美显示 . BufferedImage testImage = ImageIO.read（filepath）;

float[][] sobelFilter = { { -1, 0, 1}, 
                  { -2, 0, 2}, 
                  { -1, 0, 1} }; 
testImage = SimpleImage.toGrayscale(testImage); 
testImage =  SimpleImage.convolutionFilter(testImage, sobelFilter); 
//use some swing functions to display image

如果我只能转换为灰度，我会得到正确的结果，如果我只是应用JUST过滤器我会得到正确的结果 . 如果我按原样完成，我会弹出一个空白GUI屏幕 . 如果我交换它们执行的顺序（先过滤然后转换为灰度），我会得到结果 .

我认为灰度转换过程的一些事情搞砸了卷积

toGrayscale应该将图像转换为灰度

convolutionFilter应该采用2D图像滤镜，将其展开为1D数组，然后对processedImage进行卷积并返回结果 .

public class SimpleImage { 
public static BufferedImage toGrayscale(BufferedImage processedImage) { 
     BufferedImage tempImage = new BufferedImage(processedImage.getWidth(), processedImage.getHeight(), processedImage.getType()); 
     BufferedImageOp op = new ColorConvertOp(ColorSpace.getInstance(ColorSpace.CS_GRAY), null);  
     tempImage = op.filter(processedImage, null);  
     return tempImage; 
}   


public static BufferedImage convolutionFilter(BufferedImage processedImage, float[][] filter2D) {     
    BufferedImage tempImage = new BufferedImage(processedImage.getWidth(), processedImage.getHeight(), processedImage.getType()); 
    int columns = filter2D.length; 
    int  rows= filter2D[0].length; 
    //Unrolls a 2D filter into a 1D filter 
    float[] filter1D = new float[columns*rows]; 
    for (int j = 0; j<rows; j++) { 
            for (int i= 0; i< columns; i++ ) { 
            filter1D[j*columns + i] = filter2D[j][i]; 
        } 
    } 
    //creates Kernal and convolution operator 
    Kernel kern = new Kernel(rows, columns, filter1D); 
    ConvolveOp op = new ConvolveOp(kern); 
    //apply filtering  
    tempImage = op.filter(processedImage, null); 
    return tempImage; 

    } 
 }