Patent attributes
An adhered substance detection apparatus includes an obtaining portion configured to obtain captured image data outputted from an imaging portion, a detection portion configured to detect presence or absence of an adhered substance of each of plural regions of an imaging surface of the imaging portion on the basis of the captured image data, and a judgement portion configured to distinguish a reliable region and an unreliable region from each other, a reliability property of predetermined arithmetic processing performed by a processing apparatus with the use of the captured image data is kept to be equal to or greater than a predetermined value in the reliable region, and the reliability property is less than the predetermined value in the unreliable region.