1. An image acquisition apparatus, the apparatus comprising: a scanning unit configured to scan an object to be examined with a measurement light; a first acquisition unit configured to acquire an image of the object to be examined based on return light from the object to be examined, to which the measurement light is irradiated; a second acquisition unit configured to acquire information which indicates movement of the object to be examined based on a plurality of images acquired by the first acquisition unit; a control unit configured to control the scanning unit based on the information which indicates the movement of the object to be examined; and a registration unit configured to perform registration of the plurality of images acquired by the first acquisition unit, the plurality of images including an image of the object to be examined acquired by the first acquisition unit based on the return light from the object to be examined of the measurement light which is scanned by the scanning unit controlled by the controlling unit.