US Patent 7548312 Measuring device for ingredient detection

A measuring device has a sensor for registering at least one parameter selected from the group consisting of at least one ingredient, at least one property, and both, of a material being investigated by the sensor, the sensor including at least one illumination source which directs at least one light beam toward the material to be investigated, at least one reference object for calibrating the measuring device, and an illumination source configured so that a portion of a light beam from the illumination source is redirected toward the reference object.