Question

What does this code line means and how can I convert this code into javacv?

gray = Scalar::all(255);

This is whole code which related to this code line.

Mat src = imread("in.jpg"), gray;

cvtColor(src, gray, CV_BGR2GRAY);
threshold(gray, gray, 230, 255, THRESH_BINARY_INV);
vector<Vec4i> hierarchy;
vector<vector<Point> > contours;
findContours(gray, contours, hierarchy, CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE);

gray = Scalar::all(255);

Please can some one explain about this ?

Answer 1

As I mentioned in my comment, it is used to set the gray image to white.

What is its benefit? It can be said only if we know what is this code for or see the full code.

Regarding Java, OpenCV has now some android samples, in which you can find Java codes.

You can check them. I saw a similar function there : mWhilte = Scalar.all(255);

Also check the JavaCV samples : http://code.google.com/p/javacv/wiki/OpenCV2_Cookbook_Examples_Chapter_2