Fig. 5, the first-order difference

Fig. 5, the first-order difference change chart of CIE 1931 standard colorimetric observer in the smooth calculation of X stimulus value, in which a chart is the X stimulus value chart; the yellow line of B and C charts is the first-order difference chart of X stimulus value, and the red line is the first-order difference chart of smooth x stimulus value; the red line of C chart is the first-order difference chart of large and small smooth x stimulus value; D chart is the overlap chart of X stimulus value and its smooth value, and the red line is the smooth value of X stimulus value Figure, the yellow line below is the figure of X stimulus value.