A method and apparatus for estimating or measuring a physical area or physical volume of an object of interest in one or more images captured using an endoscope are disclosed. According to the present method, one or more structured-light images and one or more regular images captured using an imaging apparatus are received. An object of interest in the regular images is determined. Distance information associated with the object of interest with respect to the imaging apparatus is derived from the structured-light images. The physical area size or physical volume size of the object of interest is determined based on the regular images and the distance information. The imaging apparatus can be a capsule endoscope or an insertion endoscope.