An image quality measure for image communication

In this paper. we propose an image qualiy iiteasure thor closely reseritbles the image qualiv measure used by the human visual sysiem. I n ourapplicotion. we are tiore concerned with localized errors due to trammission than the global errors due to conipression. a id we develop an approach that is appropriate for this purpose. We use psychophysicnl experiments to derennine the r,iribility rltreshold level for each frequency con~ponou of each inlage block The visibiliy tliresliold levels are adjusted according to the background loriation and ifltensiy ofthe image block. Only those f‘equenq cornponents ofan error tlznr exceed the corresponding bresliold level are included in the conputation of the propnsrd inlage quality measure. n e propoposed image quality measure gives the PSNR of the errors that are visible to the eye and thepercentage area ofthe extent of the visible errors in the image.