模板匹配 - 为什么结果矩阵小于指定值？

Question

所以我正在使用 OpenCVCameraView 从输入图像中为特定区域进行模板匹配。下面是我的代码的样子。

Mat input;
Rect bigRect = ...; //specific size

public Mat onCameraFrame(CvCameraViewFrame inputFrame) {
    input = inputFrame.rgba();
    ...
}

public void Template(View view) {
    Mat mImage = input.submat(bigRect);
    Mat mTemplate = Utils.loadResource(this, R.id.sample, Highgui.CV_LOAD_IMAGE_COLOR);
    Mat mResult = new Mat(mImage.rows(), mImage.cols(), CvType.CV_32FC1); // I use the same size as mImage because mImage's size is already smaller than inputFrame

    Imgproc.cvtColor(mImage, mImage, Imgproc.COLOR_RGBA2RGB); //convert is needed to make mImage and mTemplate to be the same type

    Imgproc.matchTemplate(mImage, mTemplate, mResult, match_method);        
    Core.normalize(mResult, mResult, 0, 1, Core.NORM_MINMAX, -1, new Mat());

    mResult.convertTo(mResult, CvType.CV_8UC1); // I convert the matrix because I need to show it to imageview via bitmap

    Bitmap bmResult1 = Bitmap.createBitmap(mImage.width(), mImage.height(), Bitmap.Config.RGB_565);
    Bitmap bmResult2 = Bitmap.createBitmap(mResult.width(), mResult.height(), Bitmap.Config.RGB_565);
    Utils.matToBitmap(mImage, bmResult1);
    Utils.matToBitmap(mResult, bmResult2);
    ImageView1.setImageBitmap(bmResult1);
    ImageView2.setImageBitmap(bmResult2);
}

我尝试使用 toString() 输出矩阵并得到这些结果：

mImage: Mat [250*178*CV_8UC3, isCont=true, isSubmat=false, ...]
mResult: Mat [180*94*CV_8UC1, isCont=true, usSubmat=false, ...]

我的问题是：

尽管已经声明 mResult 尺寸基于 mImage 尺寸，但为什么 mResult 尺寸小于 mImage？
原来使用CV_8UC1类型，内容只有黑色或白色，而mResult应该有浮动值，但Utils.matToBitmap方法不支持垫类型其他比 CV_8UC1、CV_8UC3 和 CV_8UC4。有没有办法让CV_32FC1显示给Bitmap，它显示mResult的真实灰度？

Answer 1

Why the mResult size is smaller than mImage despite already declared that mResult size is based on mImage size?

由于模板匹配基本上是一个空间卷积，当对高度为 H 和 h 的图像执行时，结果将是 H-h+1。与结果宽度相同 (W-w+1)。但是你仍然可以resize结果返回(mImage.rows(), mImage.cols()) 在模板匹配之后。

Turns out that by using CV_8UC1 type, the content is only available in black or white, while mResult is supposed to have floating value, but Utils.matToBitmap method doesn't support mat types other than CV_8UC1, CV_8UC3, and CV_8UC4. Is there any way to show CV_32FC1 to Bitmap that it shows the real grayscale of mResult?

关键就在这两行，我觉得：

Core.normalize(mResult, mResult, 0, 1, Core.NORM_MINMAX, -1, new Mat());
mResult.convertTo(mResult, CvType.CV_8UC1); // I convert the matrix because I need to show it to imageview via bitmap

您不能将其规范化为取 0 到 255 之间的值吗？

Core.normalize(mResult, mResult, 0, 255, Core.NORM_MINMAX, -1, new Mat());

模板匹配 - 为什么结果矩阵小于指定值？

Template Matching - Why the result matrix is smaller than specified?

java

android

opencv

image-processing

template-matching