Perceptual linearization as a standard for displays

In image display, the numerical data in the computer memory are mapped to luminance val ues on the screen. These luminances are transformed into a brightness impression by the observer. For medical images, the data often represent information with a quantitative meaning, such as the radiation absorption by tissues. It is, therefore, crucial for this information to be accurately transferred to brightness. Perceptual linearization means that equal steps in the data evoke equal steps in brightness sensation. Perceptually linear grey scales were formed by using magnitude estimation of brightness in simple stimuli. The resulting linearized lookup tables were then applied to complex images. Brightness matching was used to determine grey levels at specified image locations, prior to and after linearization. Results show that the accuracy in the matching task is not worsened after perceptual linearization. Hence, this method could be considered for standardization of the display.