A computer-implemented method for evaluating an object disposed on an upper surface of an object holder , the method comprising: acquiring (S204;S206;S1904) at least one first frame representing a captured portion of the object, while the object holder is successively positioned (S202; S1902) at each of a plurality of locations; acquiring (S204;S206;S1906) at least one second frame representing a captured portion of at least one other surface of the object holder while the object holder is positioned at each of the plurality of locations; determining (S208;S210;S212;S214) at least one spatial characteristic associated with the captured portion of the object, based on at least one of the acquired frames, wherein the determining includes: determining (S208;S210) values of a plurality of optical markers captured in each second frame, at least two of the optical markers having different characteristics selected out of a group of color, size, shape or distances between the optical markers, wherein the optical markers are arranged in an array and determining (S212;S214) at least one of coordinates associated with the values and an orientation of the captured portion of the at least one other surface, and for each first frame, translating (S216; S1908) coordinates associated with the captured portion of the object, based on the orientation and the coordinates. acquiring (S204;S206;S1904) at least one first frame representing a captured portion of the object, while the object holder is successively positioned (S202; S1902) at each of a plurality of locations; acquiring (S204;S206;S1906) at least one second frame representing a captured portion of at least one other surface of the object holder while the object holder is positioned at each of the plurality of locations; determining (S208;S210;S212;S214) at least one spatial characteristic associated with the captured portion of the object, based on at least one of the acquired frames, wherein the determining includes: determining (S208;S210) values of a plurality of optical markers captured in each second frame, at least two of the optical markers having different characteristics selected out of a group of color, size, shape or distances between the optical markers, wherein the optical markers are arranged in an array and determining (S212;S214) at least one of coordinates associated with the values and an orientation of the captured portion of the at least one other surface, and for each first frame, translating (S216; S1908) coordinates associated with the captured portion of the object, based on the orientation and the coordinates. determining (S208;S210) values of a plurality of optical markers captured in each second frame, at least two of the optical markers having different characteristics selected out of a group of color, size, shape or distances between the optical markers, wherein the optical markers are arranged in an array and determining (S212;S214) at least one of coordinates associated with the values and an orientation of the captured portion of the at least one other surface, and for each first frame, translating (S216; S1908) coordinates associated with the captured portion of the object, based on the orientation and the coordinates. <EOS>