Abstract: An electronic device that includes a display and an eye tracker configured to collect eye tracking data regarding a gaze of one or more of a user's eyes across the display is disclosed herein. The electronic device includes processing circuitry that is operatively coupled to the display and configured to foveate one or more areas of the display according to the eye tracking data. If the eye tracking data input is lost, the processing circuitry is configured to recover from the loss of eye tracking data by changing one or more aspects of the foveated areas (e.g., size, resolution, etc.) until a threshold is satisfied. As time elapses since loss of eye tracking, the foveated areas move toward a center or a salient region of the display.

Abstract: An electronic device may include a display for displaying image content to a user and dynamic image stabilization circuitry for dynamically compensating the image content if the device is moving unpredictably to help keep the image content aligned with the user's gaze. The electronic device may include sensors for detecting the displacement of the device. The dynamic image stabilization circuitry may include a usage scenario detection circuit and a content displacement compensation calculation circuit. The usage scenario detection circuit receives data from the sensors and infers a usage scenario based on the sensor data. The content displacement compensation calculation circuit uses the inferred usage scenario to compute a displacement amount by which to adjust image content. When motion stops, the image content may gradually drift back to the center of the display.

Abstract: In some implementations, a mobile computing device may participate in the calibration of an output signal of a media device. This calibration process includes storing device-specific calibration data which is related to properties of a light sensor of the mobile device. The mobile device then detects of properties of light emitted by the display device during a presentation to obtain sensor values related to light emitted by the display device during the presentation. The calibration process may also ensure that the mobile device is proximate to the display device prior to obtaining the sensor values. The collected sensor values are adjusted using device-specific calibration data stored to the mobile device to normalize the sensor values relative to a baseline. These normalized sensor values are sent to the media device for use in adjusting the output signal based on the normalized sensor values.

Abstract: An electronic device may include a display that displays virtual reality content. Control circuitry may estimate a brightness adaptation state of a user that is wearing the electronic device. The control circuitry may select a tone mapping curve and brightness level for the virtual reality content based on the user's adaptation state. To estimate the user's adaptation state, the control circuitry may gather ambient light information from an ambient light sensor, may gather physiological attributes of the user such as blink rate, pupil size, and eye openness from a camera, and may gather gaze position information from gaze detection circuitry. The control circuitry may optimize the brightness of the display based on the user's current adaptation state, or the control circuitry may shift the brightness of the display away from the user's adaptation level to help guide the adaptation state to the desired level.

Abstract: A head-mounted device may include a display that generates content and an optical system through which the content is viewable. The head-mounted device may include a lighting system that illuminates a periphery of the optical system. When the user places the device on his or her head in a brightly lit environment, control circuitry may operate the lighting system to provide bright illumination to the user's peripheral vision. The lighting system may gradually decrease in brightness until the user transitions from a bright-adapted state to a dark-adapted state. When the user is partially or fully dark-adapted, the lighting system may be turned off and the display may be turned on. In some arrangements, an ambient light sensor may measure ambient light conditions outside of the electronic device and the control circuitry may control the lighting system based on the ambient lighting conditions.

Abstract: Aspects of the subject technology relate to gaze-dependent visual encryption of electronic device displays. Each display frame that is displayed on the electronic device display may include a clear-display region around the user's gaze location and an obscured region outside the clear-display region. In this way, only the display content that the user is actively viewing is recognizable and understandable and an onlooker such as an unwanted observer looking over the user's shoulder is unable to understand what is displayed. The obscured region of each display frame may be generated such that the overall look and structure of that region is unchanged, but the content is unintelligible. In this way, the visual experience of the user is not disrupted or distracted by the visual encryption and the eye of the onlooker is not guided to the clear-display region by the visual encryption.

Abstract: An electronic device may be provided with a display. Standard and high dynamic range content may be produced by content generators operating on control circuitry. Standard dynamic range content and high dynamic range content may be simultaneously displayed. Tone mapping parameters may be produced by a tone mapping engine for use in displaying the standard and high dynamic range content. The tone mapping parameters may be selected based on factors such as ambient light level, user brightness setting, content statistics, display characteristics, point of gaze information, power consumption information, and per-window information. Tone mapping parameters may be selected to accommodate simultaneous display of standard and high dynamic range content. Tone mapping parameters may be temporarily modified in response to a user's point of gaze switching between standard dynamic range content and high dynamic range content.

Abstract: An electronic device may include a display having an array of display pixels and having display control circuitry that controls the operation of the display. The display control circuitry may adaptively adjust the spectral characteristics of display light emitted from the display to achieve a desired effect on the human circadian system. For example, the display control circuitry may adjust the spectral characteristics of blue light emitted from the display based on the time of day such that a user's exposure to the display light may result in a circadian response similar to that which would be experienced in natural light. The spectral characteristics of blue light emitted from the display may be adjusted by adjusting the relative maximum power levels provided to blue pixels in the display or by shifting the peak wavelength associated with blue light emitted from the display.

Abstract: A display calibration system may include a first electronic device that includes an ambient light sensor and a display to be calibrated in a second electronic device. The first electronic device may generate test patterns to be displayed on the display. The ambient light sensor may receive light emitted from the display based on the test patterns to generate display color space data. The first electronic device may generate calibration data for the display based on the display color space data and a target reference color space. The second electronic device may store the calibration data and use the calibration data to generate more accurate images. Because the first electronic device may include other functionalities other display calibration, specialized display calibration equipment may be omitted. Additionally, a third electronic device that acts as an intermediary between the first and second electronic devices.

Abstract: An electronic device may have components that experience performance variations as the device changes orientation relative to a user. Changes in the orientation of the device relative to the user can be monitored using a motion sensor. A camera may be used to periodically capture images of a user's eyes. By processing the images to produce accurate orientation information reflecting the position of the user's eyes relative to the device, the orientation of the device tracked by the motion sensor can be periodically updated. The components may include audio components such as microphones and speakers and may include a display with an array of pixels for displaying images. Control circuitry in the electronic device may modify pixel values for the pixels in the array to compensate for angle-of-view-dependent pixel appearance variations based on based on the orientation information from the motion sensor and the camera.

Abstract: An electronic device may include a display having an array of display pixels and having display control circuitry that controls the operation of the display. The display control circuitry may operate the display in different modes. In a paper mode, display control circuitry may use stored spectral reflectance data to adjust display colors such that the colors appear as they would on a printed sheet of paper. In a low light mode when the ambient light level is below a threshold, the light emitted from the display may be adjusted to mimic the appearance of an incandescent light source. In a bright light mode when the ambient light level exceeds a threshold, the light emitted from the display may be adjusted to maximize readability in bright light. The target white point of the display may be adjusted based on which mode the display is operating in.

Abstract: An electronic device may be provided with a display. A content generator may generate frames of image data to be displayed on the display. Control circuitry in the electronic device may be used in implementing a tone mapping engine. The tone mapping engine may display content from the content generator on the display in accordance with a content-luminance-to-display luminance mapping. The content-luminance-to-display-luminance mapping is characterized by tone mapping parameters such as a black level, a reference white level, and a specular white level. The tone mapping engine may adjust the tone mapping parameters based on ambient light levels, user brightness settings, content statistics, and display characteristics.

Abstract: Aspects of the subject technology relate to electronic devices with displays and ambient light sensors. An electronic device modifies the color of images to be displayed based on measured ambient light color. The modification is performed in a perceptually uniform color space and includes a determination of a bleaching effect of reflected ambient light, and a determination of a color correction factor to be applied within the perceptually uniform color space, based on the determined bleaching effect. The modification may also include an application of a strength factor that mitigates out-of-gamut colors in color compensated images.

Abstract: Techniques are provided for implementing near-view notification techniques. In some instances, a viewing distance with respect to a display screen of an electronic device may be determined. In accordance with a determination that the viewing distance is above a distance threshold, content may be presented on the display screen. In accordance with a determination that the viewing distance is under a distance threshold, until the viewing distance returns to being above the distance threshold, a visual notification may be displayed. The visual notification may disrupt the content presented on the display screen.

Abstract: An electronic device may have a main display and an ancillary display that forms a dynamic function row. The device may also have a backlit keyboard with glyphs. The keyboard may have light-emitting diodes that emit backlight illumination. The backlight illumination has a backlight illumination color and intensity. A color ambient light sensor may measure ambient light color and intensity. Control circuitry in the laptop computer may make white point adjustments to the main and ancillary displays. White point adjustments may be made based on factors such as the backlight illumination intensity, information on the nominal white point of a display (which may be comparable to the color of the backlight illumination), information on the ambient light color and intensity, and a white point adaptation scaling factor.

Abstract: A head-mounted device may include a display that generates content and an optical system through which the content is viewable. The head-mounted device may include a lighting system that illuminates a periphery of the optical system. When the user places the device on his or her head in a brightly lit environment, control circuitry may operate the lighting system to provide bright illumination to the user's peripheral vision. The lighting system may gradually decrease in brightness until the user transitions from a bright-adapted state to a dark-adapted state. When the user is partially or fully dark-adapted, the lighting system may be turned off and the display may be turned on. In some arrangements, an ambient light sensor may measure ambient light conditions outside of the electronic device and the control circuitry may control the lighting system based on the ambient lighting conditions.

Abstract: An electronic device may be provided with a display mounted in a housing. Color ambient light sensors may make measurements of ambient light intensity and color through windows in an inactive border region of the display or other portions of the device. The electronic device may process the ambient light measurements based on ambient light information from the ambient light sensors and based on information from additional sensors such as an image sensor, a force sensor, a capacitive touch sensor, a proximity sensor, an orientation sensor, and other devices. Control circuitry in the electronic device may produce reliable ambient light measurements by combining readings from multiple reliable sources and by discarding readings from ambient light sensors that are blocked by a user's fingers or other external objects. Display color cast and intensity may be adjusted based on ambient light information.

Abstract: Aspects of the subject technology relate to gaze-dependent visual encryption of electronic device displays. Each display frame that is displayed on the electronic device display may include a clear-display region around the user's gaze location and an obscured region outside the clear-display region. In this way, only the display content that the user is actively viewing is recognizable and understandable and an onlooker such as an unwanted observer looking over the user's shoulder is unable to understand what is displayed. The obscured region of each display frame may be generated such that the overall look and structure of that region is unchanged, but the content is unintelligible. In this way, the visual experience of the user is not disrupted or distracted by the visual encryption and the eye of the onlooker is not guided to the clear-display region by the visual encryption.

Abstract: An electronic device such as a desktop computer or other device may have an electronic device housing with front and rear faces. A display may be mounted on the front face. The electronic device may include multiple ambient light sensors such as a front color ambient light sensor on the front face and a rear color ambient light sensor on the rear face. The front ambient light sensor gathers a front ambient light intensity measurement and a front ambient light color measurement. The rear ambient light sensor gathers a rear ambient light intensity measurement and a rear ambient light color measurement. During operation, control circuitry in the electronic device takes action based on data from the ambient light sensors. The control circuitry may adjust a white point of the display using a combined color value that is produced using a combining function.

Abstract: An electronic device may include a display having an array of display pixels and having display control circuitry that controls the operation of the display. The display control circuitry may adaptively adjust the spectral characteristics of display light emitted from the display to achieve a desired effect on the human circadian system. For example, the display control circuitry may adjust the spectral characteristics of blue light emitted from the display based on the time of day such that a user's exposure to the display light may result in a circadian response similar to that which would be experienced in natural light. The spectral characteristics of blue light emitted from the display may be adjusted by adjusting the relative maximum power levels provided to blue pixels in the display or by shifting the peak wavelength associated with blue light emitted from the display.