% 1.4
function canny = MyCanny(img, sigma, gradThresh)
    width = 5;
    img = rgb2gray(img);
    gFilter = fspecial('gaussian', width, sigma);
    h = fspecial('sobel');
    imConv = imfilter(img, gFilter, 'conv');
    imConv_y = imfilter(imConv, h, 'conv');
    imConv_x = imfilter(imConv, h', 'conv');

    imConv_x = im2double(imConv_x);
    imConv_y = im2double(imConv_y);

    img_grad_mag = sqrt((imConv_x.^2) + (imConv_y.^2));
    img_thresh = img_grad_mag > gradThresh;

    img_grad_or = atan2(imConv_y,imConv_x);
    img_grad_or = (img_grad_or)*180/pi;

    zeroArray = zeros(size(img_thresh,1)+1,size(img_thresh,2)+1);
    zeroArray(2:size(img_thresh,1),2:size(img_thresh,2)) = img_thresh;

    newArray = zeroArray;

    for row = 2:size(newArray,1)-1
        for col = 2:size(newArray,2)-1
            p = img_grad_or(row,col);
            while (p > 360)
                p = p - 360;
            end
            switch p
                case (p >= 0 && p < 22.5 || p >= 337.5 && p <= 360 || p >= 157.5 && p < 202.5) %0 || 360 || 180
                    if (zeroArray(row,col) > zeroArray(row+1,col) && zeroArray(row,col) > zeroArray(row-1,col))
                        newArray(row,col) = zeroArray(row,col);
                    else
                        newArray(row,col) = 0;
                    end
                case (p >= 22.5 && p < 67.5 || p >= 202.5 && p < 247.5) %45 || 225
                    if (zeroArray(row,col) > zeroArray(row+1,col+1) && zeroArray(row,col) > zeroArray(row-1,col-1))
                        newArray(row,col) = zeroArray(row,col);
                    else
                        newArray(row,col) = 0;
                    end
                case (p >= 67.5 && p < 112.5 || p >= 247.5 && p < 292.5) %90 || 270
                    if (zeroArray(row,col) > zeroArray(row,col+1) && zeroArray(row,col) > zeroArray(row,col-1))
                        newArray(row,col) = zeroArray(row,col);
                    else
                        newArray(row,col) = 0;
                    end
                case (p >= 112.5 && p < 157.5 || p >= 292.5 && p < 337.5) %135 || 315
                    if (zeroArray(row,col) > zeroArray(row+1,col-1) && zeroArray(row,col) > zeroArray(row-1,col+1))
                        newArray(row,col) = zeroArray(row,col);
                    else
                        newArray(row,col) = 0;
                    end
            end
        end
    end
    canny = newArray(2:size(img_thresh,1),2:size(img_thresh,2));
end