用于模板匹配的OpenCV阅读图像

Question

Im using OpenCV in java, developing with eclipse and the images are read this way for template matching.

String inFile = "C:/image.png";
Mat img = Highgui.imread(inFile);

This is nice but my images are not in my local computer. I should compare 2000 images on a server in mysql database. Saving 2000 images to my computer and then reading them does not make sense.

So what I need is that Highgui.imread(inFile) reads an image: Highgui.imread(Image inImage) or maybe Highgui.imread(File inFile) , I couldnt find the java source to edit/modify. I need someway to convert my images which will be coming from the mysql DataBase to Mat type for comparison(template matching) ...

More info: I have a mysql table with columns: ID, Name, Description, Image1, Image2. The type of Image1 and 2 columns are "mediumblob" and when you right click to the column Image1 or Image2 in "MySQL Workbench" I choose "Open Value in Editor" then there are 3 tabs; Binary, Text, Image, at Image my image is displayed perfectly. The type of Images are png. In the end I want to Compare Image1 with Image2. Image2 is inFile and Image1 is templateFile.

I'm sorry I thought my question was clear. I will try to rephrase it. I have a local computer and a server. The images are stored in the mysql database on server. I want to run an application from my local computer that retrieves/accesses 2 images on the server and then compares them via OpenCV template matching. Afaik you can't access a column of mysql with /server/home/user/mysql/image_table/mypicture.png , I'm writing this because of "guneykayim" 's suggestion. So how Im planning to retrieve the images, havent tried yet but the plan is :

Blob imageBlob = resultSet.getBlob(yourBlobColumnIndex);
InputStream binaryStream = imageBlob.getBinaryStream(0, imageBlob.length());

Or

InputStream binaryStream = resultSet.getBinaryStream(yourBlobColumnIndex);

Or

try{
    Class.forName(driverName);
    con = DriverManager.getConnection(url+dbName,userName,password);
    Statement stmt = con.createStatement();
    ResultSet rs = stmt.executeQuery("select image from image");
    int i = 0;
    while (rs.next()) {
        InputStream in = rs.getBinaryStream(1);
        OutputStream f = new FileOutputStream(new File("test"+i+".jpg"));
        i++;
        int c = 0;
        while ((c = in.read()) > -1) {
            f.write(c);
        }
        f.close();
        in.close();
    }
}catch(Exception ex){
    System.out.println(ex.getMessage());
}

My Question: I want to compare 2 images, I retrieved from the mysql database.

Highgui.imread(); 

This method expects a String but I want to give the InputStream or the OutputStream file... Like I said I don't want to save 2000 images on my local computer. I'm open for alternative ways as well.

Final Simplest Rephrasing : How can I use template matching of java OpenCV on 2 images stored on a mysql database.

In other words how can I convert InputStream object to Mat object?

Thanks for reading.

Answer 1

我在这里找到了对这个家伙的荣誉，他是我的英雄:)完美工作，如果您想要原始颜色而不是灰度的图像，则应将Highgui.IMREAD_GRAYSCALE更改为Highgui.IMREAD_UNCHANGED以获取更多信息， 请检查