Use of digital reflection devices for measurement using hue-based optical sensors

In this paper the hue, or H component of the HSV (hue, saturation, value) color space, is used as analytical parameter for bitonal optical sensors. This parameter is characterized by its robustness to variations in the imaging device, illuminant, and sensor membrane. It has a higher precision than either traditional optical parameters, such as absorbance or transflectance, or other color parameters such as RGB coordinates. Here the hue is calculated from digital images obtained in reflection mode (digital camera) rather than images in transmission mode (digital scanner) as demonstrated in previous work. The stability of the H parameter, makes it possible to greatly simplify the procedure used for the optical sensors as well as to use ubiquitous digital cameras to acquire the image.