Abstract: Disclosed are various techniques for generating image specific global tone curves and residual gain maps based on multiple images. A gain map is generated based on a comparison of a first image to a second image. A gain map scatter plot is constructed based on the gain map values and channel values of either the first image or the second image. An image specific global tone curve is determined by curve fitting to the gain map scatter plot. A residual gain map is generated based on a comparison of the gain map to a reconstructed gain map derived from the image specific global tone curve. An approximation of the second image can be constructed using the image specific global tone curve and the first image. A replica of the second image can be constructed using the image specific global tone curve, the residual gain map, and the first image.

Abstract: The embodiments described herein set forth techniques for adjusting gain maps for digital images. In particular, headroom metrics, midtone metrics, highlight metrics, shadow metrics, diffuse white metrics, etc., or some combination thereof, can be determined based on characteristics of a given digital image, characteristics of a scene that corresponds to the digital image, circumstances under which the scene was captured, and so on. These metrics, or some combination thereof, can then be used to modify a gain map associated with the digital image. Additionally, a histogram of the modified gain map can be generated, where, in turn, the histogram can be used to modify any of the aforementioned metrics. Subsequently, the histogram and/or any combination of the modified metrics can be used to adjust the modified gain map.

Abstract: An electronic device may have a display and a camera. Control circuitry in the device can gather information on a user's point of gaze using a gaze tracking system and other sensors, can gather information on the real-world image such as information on content, motion, and other image attributes by analyzing the real-world image, can gather user vision information such as user acuity, contrast sensitivity, field of view, and geometrical distortions, can gather user input such as user preferences and user mode selection commands, and can gather other input. Based on the point-of-gaze information and/or other gathered information, the control circuitry can display the real-world image and supplemental information on the display. The supplemental information can include augmentations such as icons, text labels, and other computer-generated text and graphics overlaid on the real world image and can include enhanced image content such as magnified portions of the real-world image.

Abstract: A head-mountable display device includes a housing defining a front opening and a rear opening, a display screen disposed in the front opening, a display assembly disposed in the rear opening, a first securement strap coupled to the housing, the first securement strap including a first electronic component, a second securement strap coupled to the housing, the second securement strap including a second electronic component, and a securement band extending between and coupled to the first securement strap and the second securement strap.

Abstract: This application describes techniques for preprocessing images to improve gain map compression outcomes. A gain map can be generated by comparing a first image to a second image and subsequently compressed to form a compressed gain map. The compressed gain map can combined with a compressed version of the first image to form a compressed enhanced image. The compressed enhanced image can be later uncompressed to generate an uncompressed version of the first image and the gain map applied to the uncompressed version of the first image to generate a version of the second image to provide for reproduction on a target display. The compressed version of the first image and the compressed gain map can be generated separately by an image compression module and a gain map compression module or jointly by a combined gain map generation and compression module.

Abstract: Disclosed are various techniques for utilizing gain maps. According to some embodiments, one technique for utilizing a gain map comprises (1) accessing an enhanced image that includes a high dynamic range (HDR) image and the gain map, (2) extracting the HDR image and the gain map from the enhanced image, (3) generating a standard dynamic range (SDR) image using the HDR image and the gain map, (4) receiving and applying first modification instructions against the HDR image, (5) generating second modification instructions based on at least the first modification instructions, (6) applying the second modification instructions to the SDR image, (7) generating a second gain map by comparing the HDR image against the SDR image or vice-versa, and (8) embedding the second gain map into the HDR image or the SDR image.

Abstract: Disclosed are various techniques for generating gain maps. According to some embodiments, one technique for generating a gain map includes the steps of (1) accessing a high dynamic range (HDR) image, (2) accessing a standard dynamic range (SDR) image, (3) for each pixel shared between the HDR and SDR images: plotting the pixel onto a graph, wherein an HDR value of the pixel is plotted on a Y-axis of the graph and an SDR value of the pixel is plotted on an X-axis of the graph, (4) establishing a first curve that represents an approximation of the plotted pixels, (5) inverting the first curve to establish a second curve, (6) applying the second curve against the plotted pixels to establish replotted pixels, (7) generating the gain map based on the replotted pixels, and (8) embedding the gain map into the HDR image.

Abstract: Embodiments disclosed herein are directed to devices and methods for performing spatially-varying brightness correction of a flash image. The spatially-varying brightness correction utilizes a set of images that includes one or more images captured under flash illumination and one or more images captured without flash illumination, which are used to decompose one of the flash images or an image generated therefrom into a flash contribution image and an ambient contribution image. The flash contribution image and the ambient contribution image are recombined to generate a corrected flash image, and information about the flash module and/or scene is used to adjust the relative contributions of these images during recombination.

Abstract: An electronic device may have a display and a camera. Control circuitry in the device can gather information on a user's point of gaze using a gaze tracking system and other sensors, can gather information on the real-world image such as information on content, motion, and other image attributes by analyzing the real-world image, can gather user vision information such as user acuity, contrast sensitivity, field of view, and geometrical distortions, can gather user input such as user preferences and user mode selection commands, and can gather other input. Based on the point-of-gaze information and/or other gathered information, the control circuitry can display the real-world image and supplemental information on the display. The supplemental information can include augmentations such as icons, text labels, and other computer-generated text and graphics overlaid on the real world image and can include enhanced image content such as magnified portions of the real-world image.

Abstract: Eyewear such as a head-mounted device may include display-optimized lenses. The lenses may be optimized for viewing an external display while also providing sun protection for the user's eyes. The external display may form part of a handheld electronic device that serves as a controller for the head-mounted device. The lenses in the head-mounted device may reduce ambient light brightness while maintaining the brightness of the external display so that the user can use the external display while wearing the head-mounted device. The user may, for example, provide touch input to the external display to adjust display content on the head-mounted display. The lenses may include a polarizer and a color filter having a transmission spectrum curve with peaks corresponding to the primary colors of the external display. The lenses may be removable clip-on lenses and the light filter may be an electrochromic filter.

Abstract: An electronic device may have a display and a camera. Control circuitry in the device can gather information on a user's point of gaze using a gaze tracking system and other sensors, can gather information on the real-world image such as information on content, motion, and other image attributes by analyzing the real-world image, can gather user vision information such as user acuity, contrast sensitivity, field of view, and geometrical distortions, can gather user input such as user preferences and user mode selection commands, and can gather other input. Based on the point-of-gaze information and/or other gathered information, the control circuitry can display the real-world image and supplemental information on the display. The supplemental information can include augmentations such as icons, text labels, and other computer-generated text and graphics overlaid on the real world image and can include enhanced image content such as magnified portions of the real-world image.

Abstract: Eyewear such as sunglasses may include display-optimized lenses. The lenses may be optimized for viewing an external display and/or for viewing a display in the head-mounted device while also providing sun protection for the user's eyes. The lenses may include a polarizer and a color filter that are designed for a given target display. Lenses that are optimized for a display that emits linearly polarized light may include a linear polarizer. Lenses that are optimized for a display that emits circularly polarized light may include a circular polarizer. The circular polarizer may include a quarter wave plate and a linear polarizer. The color filter may have a transmission spectrum curve with peaks corresponding to the primary colors of the target display so that the color and brightness of display light is preserved while the brightness of sunlight is reduced.

Abstract: An electronic device such as a watch may include a display and a light sensor located behind the display. The light sensor may be used to measure the color of external objects. During color sampling operations, the display may emit light towards the external object in front of the display while the light sensor gathers color measurements. The display may emit light of different colors and the light sensor may detect an amount of reflected light for each color, which in turn may be used to determine the color of the external object. The control circuitry may use a watch-band-specific algorithm to determine the color of watch bands and may use a clothing-specific algorithm to determine the color of clothing. The control circuitry may display the color on the display so that the face of the watch matches the user's clothing or matches the user's watch band.

Abstract: A head-mounted display may display images in eye boxes. Right and left gaze tracking sensors may gather left eye gaze information from a left eye box and right eye gaze information from a right eye box. During operation in a first mode in which the right and left gaze tracking sensors are not impaired, gaze information from the right and left gaze tracking sensors may be used in presenting foveated and distortion-corrected image content on the displays and/or in otherwise operating the left and right displays. During operation in a second mode in which one of the gaze tracking sensors is impaired, gaze information for the impaired sensor may be estimated from gaze information for the unimpaired sensor in combination with an object depth estimate based on depth buffer information, vestibulo-ocular-reflex gain information, and historical information.

Abstract: Systems, methods, and devices are provided to reduce a likelihood of image burn-in on an electronic display. Such an electronic device may include image processing circuitry and an electronic display. The image processing circuitry may receive image data and analyze the image data for risk of image burn-in and, based at least in part on the analysis of the image data, reduce a risk of image burn-in at least in part by reducing a local maximum pixel luminance value in at least one of a plurality of regions of the image data over time or by reducing a dynamic range headroom of the image data. The electronic display may display the image data with a reduced risk of image burn-in on the pixels of the electronic display.

Abstract: Aspects of the subject technology relate to display circuitry for displaying both standard dynamic range (SDR) and high dynamic range (HDR) content with an HDR display. The subject technology provides a headroom-based transfer function that maintains the contrast of the SDR content whether the display is operated in the SDR or HDR mode.

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: An electronic device may be provided with a display. A content generator such as a camera may capture images in high dynamic range mode or standard dynamic range mode. The images may have associated image metadata such as face detection information, camera settings, color and luminance histograms, and image classification information. Control circuitry in the electronic device may determine tone mapping parameters for the captured images based on the image metadata. The tone mapping parameters for a given image may be stored with the image in the metadata file. When it is desired to display the image, the control circuitry may apply a tone mapping process to the image according to the stored tone mapping parameters. The algorithm that is used to determine tone mapping parameters based on image metadata may be based on user preference data gathered from a population of users.

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.