1. A method of partitioning an object from an image, the method comprising: pre-setting a reference width for an object; extracting a shadow underneath the object from an image; determining a candidate region containing the object in the image based on the extracted shadow underneath the object; acquiring an imaging width of the reference width at a location of the extracted shadow underneath the object in the image; adjusting the candidate region based on the imaging width of the reference width such that the adjusted candidate region substantially contains the object; and partitioning the adjusted candidate region as a region containing the object from the image, the method further comprising: determining whether the width of the extracted shadow underneath the object is less than the imaging width of the reference width at the location of the extracted shadow underneath the object in the image, and if the width of the extracted shadow underneath the object is less than the imaging width of the reference width at the location of the extracted shadow underneath the object in the image, the candidate region is adjusted to substantially contain the object by extending the candidate region based on a difference between the width of the extracted shadow underneath the object and the imaging width of the reference width at the location of the extracted shadow underneath the object in the image.