function Histogram = MakeHistogramRGB(InputImage, n)
    [height width] = size(InputImage);
    Histogram = zeros(1, 255);

    for i = 1 : height
        for j = 1 : width
            Start = 0;
            End = 255 / n;
            for k = 1 : n
                for l = 1 : 3
                    tmp = InputImage(i, j) - 1;
                    if (tmp >= Start & tmp <= End)
                        avg = ((Start + End) / 2);
                        uint8(avg);
                        Histogram(avg) = Histogram(avg) + 1;
                    end
                    Start = Start + End;
                    End = End + End;
                end
            end
        end
        printf("%d\n",double(i/height)*100);
    end
endfunction

function Histogram = MakeHistogramGray(InputImage, n)
    [height width] = size(InputImage);
    Histogram = zeros(1, 255);

    for i = 1 : height
        for j = 1 : width
            Start = 0;
            End = 255 / n;
            for k = 1 : n
                tmp = InputImage(i, j) - 1;
                if (tmp >= Start & tmp <= End)
                    avg = ((Start + End) / 2);
                    uint8(avg);
                    Histogram(avg) = Histogram(avg) + 1;
                end
                Start = Start + End;
                End = End + End;
            end
        end
        printf("%d\n",double(i/height)*100);
    end
endfunction

global IPD_PATH;
RGB = ReadImage(IPD_PATH + 'demos\teaset.png');
Gray = RGB2Gray(RGB);
scf(1); ShowImage(Gray, 'RGB');

hist=MakeHistogramGray(Gray,100);
scf(2);plot(hist);