| 摘要 |
A necessary signal processing is performed to a video signal in a video signal processing unit (1). The video signal is converted to obtain a DICOM gamma characteristic in a LUT unit (2) and outputted to a display unit (6). At this time, a CPU (3) refers to a memory (4), obtains an amount of brightness decrease of a backlight (7) to an amount of screen brightness increase from an output of an illuminance sensor (5), and directs a backlight driving unit (8) to decrease the brightness of the backlight (7). Thereby, the brightness of the backlight (7) is decreased by the amount of the screen brightness increase caused by lightness of a surrounding light. On the other hand, the CPU (3) corrects a black brightness by considering the amount of brightness decrease of the backlight (7) and updates the content of the LUT unit (2) so as to obtain the DICOM gamma characteristic. Thereby, good repeatability of a gray scale can be achieved even when influenced by the surrounding light. |
