A method, which is performed by an electronic device, for adjusting at least one image capturing parameter in a preview mode is disclosed. The method may include capturing a preview image of a scene including at least one text object based on a set of image capturing parameters. The method may also identify a plurality of text regions in the preview image. From the plurality of text regions, a target focus region may be selected. Based on the target focus region, the at least one image capturing parameter may be adjusted.