BFMatcher - no matches or missunderstood method signature

[sjbeskur]

Seems no matter what I try I get Zero matches. I lifted this example and images from the original OpenCV python example but I suspect I am doing something wrong in the conversion?

Any help would be much appreciated.

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let file0 = "img/box.png";
    let file1 = "img/box_in_scene.png";
    
    let img0 = imread(file0, IMREAD_GRAYSCALE)?;
    let img1 = imread(file1, IMREAD_GRAYSCALE)?;

    let mut orb = ORB::default()?;

    let mut kp_a = opencv::core::Vector::new();
    let mut des_a = Mat::default();
    let mut kp_b = opencv::core::Vector::new();
    let mut des_b = Mat::default();
    let mask = Mat::default(); // or no_array(); ??

    let _ = orb.detect_and_compute(&img0, &mask, &mut kp_a, &mut des_a, false);
    let _ = orb.detect_and_compute(&img1, &mask, &mut kp_b, &mut des_b, false);

    // let mut bf_matcher = DescriptorMatcher::create("BruteForce-Hamming")?;
    let mut bf_matcher = BFMatcher::new(NORM_HAMMING, true)?;

    let mut matches = VectorOfDMatch::new();

    // Is this correct?
    let mut query_descriptors: Vector<Mat> = Vector::new();
    query_descriptors.push(des_a);
    query_descriptors.push(des_b);

    //matcher.knn_match(&query_descriptors, &mut matches, 2,&no_array(), false);
    bf_matcher.match_(&query_descriptors, &mut matches, &no_array())?;

    println!("\n MATHES : {} --------------------" , matches.len());

    Ok(())
}