Liquid crystal display device having a control device for tone mapping

A control method for controlling a liquid crystal display device, the control method comprising:

• obtaining a first video signal;
• determining a first backlight value as a reference luminance of a backlight of the liquid crystal display device, using a first luminance characteristic of the first video signal;
• performing tone mapping on the first video signal based on the first backlight value and a peak luminance displayable by the liquid crystal display device, and outputting a second video signal obtained through the tone mapping;
• generating a control signal for local dimming control on the liquid crystal display device based on the first backlight value and the second video signal;
• and
• outputting the control signal to the liquid crystal display device,
• wherein in the performing of the tone mapping, a displayed-image peak luminance when displaying a single first frame by the liquid crystal display device is calculated from the peak luminance and the first backlight value, and the tone mapping is performed with using a tone curve having the displayed-image peak luminance as a maximum luminance, the single first frame being included in a first video to be represented by the first video signal.

A control device that controls a liquid crystal display device, the control device comprising:

• an obtainer that obtains a first video signal;
• a determiner that determines a first backlight value as a reference luminance of a backlight of the liquid crystal display device, using a first luminance characteristic of the first video signal;
• a tone map processor that performs tone mapping on the first video signal based on the first backlight value and a peak luminance displayable by the liquid crystal display device, and outputs a second video signal obtained through the tone mapping;
• and
• a generator that generates a control signal for local dimming control on the liquid crystal display device based on the first backlight value and the second video signal, and outputs the control signal to the liquid crystal display device, wherein:
• the first luminance characteristic includes a maximum value of a plurality of first luminance values and an average value of the plurality of first luminance values, the plurality of first luminance values being respectively of a plurality of first pixels that constitute a single first frame included in a first video to be represented by the first video signal,
• the first video includes a plurality of first frames including the single first frame, and
• the determiner determines, for each of the plurality of first frames, a weighted average of the maximum value and the average value of the plurality of first luminance values that constitute each of the plurality of first frames as the first backlight value.