A system and method are provided for unified visual measurement of blur and noise distortions in digital image data, the system including a processor, an input adapter in signal communication with the processor for receiving digital image data, a visual discrimination model (VDM) simulation unit in signal communication with the processor, a just noticeable difference (JND) analysis unit in signal communication with the processor, and a JND selection unit in signal communication with the processor; and the method including receiving digital image data, simulating a single-ended VDM, analyzing individual JND channels, including the responses of the highest spatial frequency channel(s), and selecting a reference JND level corresponding to low noise and blur distortions.