function z = getLinePoint(row,frame,Ishadow,Icontrast,sizex)
    str = sprintf('output_%05d.jpg',frame);
    img = rgb2gray(imread(str));
    imshad = (double(img) - Ishadow).*im2bw(1/256*Icontrast,30/256);
    for i = sizex:1
        if imshad(row,i) > 0
            z = [i,row];
            return; 
        end
    end
    z = [-1, -1];
    return;