1. A method of determining a solder paste height of solder paste printed on a circuit board, the method comprising: obtaining a two-dimensional image of the circuit board which is captured from above a solder printed surface; and determining the solder paste height corresponding to a pixel value of each of pixels of the two-dimensional image, based on height information which defines a relationship between the pixel value and the solder paste height, the pixel value being a value representing at least one of luminance of red in a RGB color model, luminance of green in the RGB color model, luminance of blue in the RGB color model, hue in a HSI color model, saturation in the HSI color model, and intensity in the HSI color model, wherein the height information shows that a difference between an intensity value and a hue value in the HSI color model corresponds to the solder paste height, and in the determining, the solder paste height is determined by calculating the difference.