Abstract: A first filter transmits a portion of incident light that has a first dominant wavelength. A second filter transmits a portion of incident light that has a second dominant wavelength different from the first dominant wavelength. An illuminance detector detects a first illuminance of light transmitted through a first filter and a second illuminance of light transmitted through a second filter. A controller adjusts the luminance of an image display on a display device according to the first illuminance and the second illuminance detected by the illuminance detector.

Abstract: A luminance adjustment system adjusts luminance of image display in a display device. The luminance adjustment system includes a controller that changes the luminance in accordance with a value of illuminance in a target space, The controller has, as operation modes, a gradual change mode in which the luminance with respect to the value of illuminance is changed in a first time, and an abrupt change mode in which the luminance with respect to the value of illuminance is changed in a second time being shorter than the first time. The controller makes switching from the gradual change mode to the abrupt change mode with a sign of an abrupt change in illuminance in the target space taken as a trigger, and then operates in the abrupt change mode for at least a fixed time after the switching.

Abstract: A display apparatus includes: an obtaining unit that obtains, from an illuminance sensor, a detected illuminance which is an illuminance at a dashboard of a vehicle detected by the illuminance sensor; an estimating unit that estimates, using the detected illuminance, an estimated illuminance which is an illuminance at a position near the head of a driver sitting in a driver's seat of the vehicle; a determining unit that determines brightness of a video, using the estimated illuminance and relationship information indicating a predetermined relationship between illuminance and brightness; and a displaying unit that displays the video at the brightness determined by the determining unit.

Abstract: A luminance adjustment system adjusts luminance of image display in a display device. The luminance adjustment system includes a controller that changes the luminance in accordance with a value of illuminance in a target space, The controller has, as operation modes, a gradual change mode in which the luminance with respect to the value of illuminance is changed in a first time, and an abrupt change mode in which the luminance with respect to the value of illuminance is changed in a second time being shorter than the first time. The controller makes switching from the gradual change mode to the abrupt change mode with a sign of an abrupt change in illuminance in the target space taken as a trigger, and then operates in the abrupt change mode for at least a fixed time after the switching.

Abstract: A display apparatus includes: an obtaining unit that obtains, from an illuminance sensor, a detected illuminance which is an illuminance at a dashboard of a vehicle detected by the illuminance sensor; an estimating unit that estimates, using the detected illuminance, an estimated illuminance which is an illuminance at a position near the head of a driver sitting in a driver's seat of the vehicle; a determining unit that determines brightness of a video, using the estimated illuminance and relationship information indicating a predetermined relationship between illuminance and brightness; and a displaying unit that displays the video at the brightness determined by the determining unit.