Measuring method and instrument comprising image sensor

A measuring device, comprising:

• an image sensor which receives light from a measuring object;
• a linearizing correction data holding unit for holding linearizing correction data that is used for correcting the output of the image sensor from which an output when a quantity of received light is zero has been subtracted as dark data so as to be made proportional to the quantity of incident light;
• a linearizing correction unit which carries out a linearizing correction process on the output of the image sensor based upon linearizing correction data stored in the linearizing correction data holding unit;
• a light-irregularity correction data holding unit for holding light-irregularity correction data that is used for correcting outputs of respective pixels so that the respective pixel outputs of the image sensor that have been obtained upon measuring a reference object, and have been corrected by the linearizing correction data are evenly adjusted;
• a light-irregularity correction unit which corrects light irregularities of the output of the image sensor on the basis of the light-irregularity correction data stored in the light-irregularity correction data holding unit, the output of the image sensor having been linearized;
• and
• a calculation unit which selects a color-developing area of the measuring object by using respective pixel outputs of the image sensor, with respect to an area that is greater than the color-developing area at least in one direction, calculates an integral value of in-plane light from the measuring object,
• wherein the calculation unit calculates the integral value of in-plane light from the measuring object by using the pixel outputs that have been subjected to the linearizing correction and the light-irregularity correction.