Patent ID: 8013891

Claim:
An illuminance acquiring device which acquires light energy corresponding to an output value of an image pickup device every different exposure time by using a correspondence relation between the output value of the image pickup device for converting intensity of sensed light into electric energy and outputting the electric energy and the light energy obtained by multiplying the intensity of light sensed by the image pickup device by the exposure time, calculates the intensity of the light sensed by the image pickup device from the light energy acquired every different exposure time and the correspondence relation, and acquires the calculated intensity of the light sensed by the image pickup device, the illuminance acquiring device comprising: a noise-model data calculating section calculating noise-model data for modeling an influence of a noise generated in the image pickup device on the output value of the image pickup device by using image pickup data obtained by means of the image pickup operation of the image pickup device every different exposure time; and an illuminance calculating section calculating the output value of the image pickup device in consideration of the influence of the noise from the noise-model data and the output value of the image pickup device when the image pickup device picks up a predetermined image, acquiring the light energy from the correspondence relation by using the calculated output value of the image pickup device in consideration of the influence of the noise, and calculating the intensity of the light, which is sensed when the image pickup device picks up the predetermined image, from the acquired light energy and the exposure time when the image pickup device picks up the predetermined image.