An apparatus comprising: means for computing a cost volume associated with a reference image; means for performing down-sampling of the cost volume into at least one level to generate at least one down-sampled cost volume; means for performing down-sampling of the reference image into the at least one level to generate at least one down-sampled reference image associated with corresponding at least one down-sampled cost volume; means for performing backward up-sampling of the at least one down-sampled cost volume into the at least one level to generate at least one backward up-sampled cost volume; means for performing backward up-sampling of the at least one down-sampled reference image associated with the at least one down-sampled cost volume into the at least one level to generate at least one backward up-sampled reference image associated with corresponding backward up-sampled cost volume; characterised by means for computing at least one color weight map associated with at least one of the cost volume and the at least one down-sampled cost volume based on an associated reference image and the at least one backward up-sampled reference image at the at least one level, the associated reference image being one of the reference image and the at least one down-sampled reference image at the at least one level; and means for determining an aggregated cost volume at the at least one level based on a weighted averaging of the at least one backward up-sampled cost volume and an associated cost volume at the at least one level, the associated cost volume being one of the cost volume and the at least one down-sampled cost volume at the at least one level, the weighted averaging being performed based on the at least one color weight map. means for computing a cost volume associated with a reference image; means for performing down-sampling of the cost volume into at least one level to generate at least one down-sampled cost volume; means for performing down-sampling of the reference image into the at least one level to generate at least one down-sampled reference image associated with corresponding at least one down-sampled cost volume; means for performing backward up-sampling of the at least one down-sampled cost volume into the at least one level to generate at least one backward up-sampled cost volume; means for performing backward up-sampling of the at least one down-sampled reference image associated with the at least one down-sampled cost volume into the at least one level to generate at least one backward up-sampled reference image associated with corresponding backward up-sampled cost volume; characterised by means for computing at least one color weight map associated with at least one of the cost volume and the at least one down-sampled cost volume based on an associated reference image and the at least one backward up-sampled reference image at the at least one level, the associated reference image being one of the reference image and the at least one down-sampled reference image at the at least one level; and means for determining an aggregated cost volume at the at least one level based on a weighted averaging of the at least one backward up-sampled cost volume and an associated cost volume at the at least one level, the associated cost volume being one of the cost volume and the at least one down-sampled cost volume at the at least one level, the weighted averaging being performed based on the at least one color weight map.