A signal processing device comprising: an image analyzer configured to: receive a first image signal corresponding to displaying at least an object and a background; identify information of the object from the first image signal; and identify information of the background from the first image signal; and an object and background processing unit to enhance a stereoscopic effect of the object by enhancing contrast of the object and reducing luminance of the background, the object and background processing unit comprising means configured to: determine a sharpness of the object using the identified information of the object; increase contrast of the object per pixel to enhance the first image signal using the identified information of the object based on the determined sharpness; decrease luminance of the background in the enhanced first image signal per pixel using the identified information of the background based on the determined sharpness; and output the enhanced first image signal in which contrast of the object has been increased and luminance of the background has been decreased; wherein the image analyzer is further configured to determine a ratio of a size of the object to the background in the first image signal, and wherein said object and background processing unit further comprises means configured to enhance a stereoscopic effect of the object wherein an amount of decrease of the luminance of the background or an amount of increase of the contrast of the object is based on the determined ratio. an image analyzer configured to: receive a first image signal corresponding to displaying at least an object and a background; identify information of the object from the first image signal; and identify information of the background from the first image signal; and receive a first image signal corresponding to displaying at least an object and a background; identify information of the object from the first image signal; and identify information of the background from the first image signal; and an object and background processing unit to enhance a stereoscopic effect of the object by enhancing contrast of the object and reducing luminance of the background, the object and background processing unit comprising means configured to: determine a sharpness of the object using the identified information of the object; increase contrast of the object per pixel to enhance the first image signal using the identified information of the object based on the determined sharpness; decrease luminance of the background in the enhanced first image signal per pixel using the identified information of the background based on the determined sharpness; and output the enhanced first image signal in which contrast of the object has been increased and luminance of the background has been decreased; determine a sharpness of the object using the identified information of the object; increase contrast of the object per pixel to enhance the first image signal using the identified information of the object based on the determined sharpness; decrease luminance of the background in the enhanced first image signal per pixel using the identified information of the background based on the determined sharpness; and output the enhanced first image signal in which contrast of the object has been increased and luminance of the background has been decreased; wherein the image analyzer is further configured to determine a ratio of a size of the object to the background in the first image signal, and wherein said object and background processing unit further comprises means configured to enhance a stereoscopic effect of the object wherein an amount of decrease of the luminance of the background or an amount of increase of the contrast of the object is based on the determined ratio.