Arithmetic processor and bone density measuring device

An arithmetic processor for measuring bone density using a correspondence relationship between a luminance value of transmitted radiation and a thickness of a reference material, the luminance value being obtained by applying radiation, which is emitted from a radiation source upon application of a tube voltage to the radiation source, to the reference material having different thicknesses and detecting the radiation transmitted through the reference material, the arithmetic processor comprising:

• a generating unit that performs an operation to generate, based on the detected luminance value, a luminance profile representing the correspondence relationship;
• a normalizing unit that performs an operation to generate a normalized profile by normalizing the luminance profile based on a maximum value and a minimum value in the generated luminance profile;
• and
• a determining unit that performs an operation to determine whether or not each luminance value corresponding to each of the different thicknesses in the normalized profile is within a range defined in advance by the tube voltage and each thickness.