Abstract: Systems, methods, and devices are provided for generating a tone mapping function used in adjusting the power consumed by a backlight of an electronic display. One such method includes sampling an image frame in framebuffer space and generating a tone mapping function in linear space. The tone mapping function may have at least two portions: a nondistorting portion that does not to distort pixels to which it applies when an intensity of a backlight of the electronic display is modified and a distorting portion that does distort pixels to which it applies when the intensity of the backlight is modified. Thereafter, the intensity of the backlight may be modified based at least in part on the nondistorting portion of the tone mapping function, the tone mapping function converted to framebuffer space, and the tone mapping function applied to the image frame or a subsequent image frame.

Abstract: Systems, methods, and devices for efficient brightness control for an organic light emitting diode (OLED) display are provided. In one embodiment, such a method may include receiving image data into a data driver of an organic light emitting diode display and transforming the image data into a logarithmic domain. A dimming control value may be subtracted from this log-encoded image data. The resulting log-encoded dimmed image data may represent a darker version of the originally received image data. Thereafter, a pixel of the organic light emitting diode display may be driven based at least in part on the dimmed image data.

Abstract: Embodiments include techniques that use color-shifting and luminance for creation and display of spatio-temporal dithered images. In one embodiment, adjacent pixels are color-shifted with respect to each other and the color values of the adjacent pixels are temporally alternated with color values of pixels in the group. In another embodiment, the luminance of group of adjacent pixels is determined and the luminance of the group is made more homogenous, spatially and temporally, by distributing color variations over a larger number of pixels so as to reduce the luminance difference between the pixel with the least luminance and the pixel with the greatest luminance. Individual color components (e.g., red, green, blue) may also be separated and used so that the color-shifts associated with each color component may be simultaneously present in different pixels.

Abstract: A method and system for modifying a pulse width modulation signal for controlling the backlit illumination intensity of a liquid crystal display. The modified pulse width modulated signal may be selected to operate with at least one pulse having a first duty cycle with the remaining pulses in the pulse width modulation signal having a second duty cycle across a selected number of pulses making up a given time period (i.e., frame). By utilizing more than one duty cycle for the pulses of the pulse width modulated signal to drive light sources in a display during a given frame, the overall number of backlit illumination intensities for the liquid crystal display may be increased. By distributing the differing pulse duty cycles within a group of pulses of within a frame, visible artifacts may be reduced.

Abstract: Systems, methods, and devices are provided for temporal filtering of tone mapping slopes used in adjusting the power consumed by a backlight of an electronic display. One such method involves computing a current first target slope of an intermediate tone mapping function based at least in part on characteristics of a current image frame and temporally filtering the current first target slope to obtain a current first transition slope. A current backlight intensity of the display and a current final tone mapping function may be determined based at least in part on the current first transition slope. The current final tone mapping function may be applied to the current image frame or a subsequent image frame.

Abstract: A method for controlling characteristics of an electronic device based on ambient light levels is provided. In one embodiment, the method includes receiving light at an ambient light sensor of a device and measuring components, such as color components, of the visible light. The component levels may be weighted differently by factors that vary based on the intensity of the light received by the ambient light sensor. Also, the brightness level of a light source in the device or color output of the device may be controlled based on the weighted component levels. Additional methods, systems, and devices relating to control of an electronic device based on sensed ambient light are also disclosed.

Abstract: Systems, methods, and devices are provided for histogram generation and evaluation used in adjusting the power consumed by a backlight of an electronic display. One such method involves generating a pixel brightness histogram of an image frame passing through a pixel pipeline in a nonlinear space. One or more pixel brightness values from the histogram may be selected before being converted from the nonlinear space into a linear space. A tone mapping function and backlight intensity are determined based at least in part on the one or more pixel brightness values in the linear space. The resulting tone mapping function is converted to the nonlinear space and applied to the image frame or a subsequent image frame in the pixel pipeline. The pixels of the image frame to which the nondistorting portion of the tone mapping function is applied may appear substantially undistorted despite a reduction in backlight intensity.

Abstract: Methods and devices are provided for controlling the brightness of a display for an electronic device based on ambient light conditions. In one embodiment, an electronic device may employ one or more brightness adjustment profiles that define response rates for changing brightness levels based on ambient light levels. The response rates may vary depending on the magnitude and/or direction of change in the ambient light levels. In certain embodiments, the response rates may be designed to approximate the physical response of the human vision system. Further, in certain embodiments, noise reduction techniques may be employed by adjusting the response rates based on the magnitude of the change in the ambient light level and/or based on whether the display is operating at steady state or executing a brightness adjustment.

Abstract: A method for controlling characteristics of an electronic device based on ambient light levels is provided. In one embodiment, the method includes receiving light at an ambient light sensor of a device and measuring components, such as color components, of the visible light. The component levels may be weighted differently by factors that vary based on the intensity of the light received by the ambient light sensor. Also, the brightness level of a light source in the device or color output of the device may be controlled based on the weighted component levels. Additional methods, systems, and devices relating to control of an electronic device based on sensed ambient light are also disclosed.

Abstract: A system and method for characterizing the power and luminance values for a display. This may include testing a device to determine a luminance value for a display of a given device at a given current and determining whether the first current is to be adjusted during future uses based on a comparison of the luminance with at least one threshold value. This may also include storing an adjusted current value if it is determined that the first current is to be adjusted.

Abstract: Methods and devices are provided for controlling the brightness of a display for an electronic device based on ambient light conditions. In one embodiment, an electronic device may employ one or more brightness adjustment profiles for changing the brightness of a display based on the ambient light level. The brightness adjustment profiles may include two or more sections, each corresponding to different ambient light levels, which may be adjusted independently of one another. The different sections may allow a user to customize brightness adjustments for different ambient light conditions. In certain embodiments, the slope and/or offset of a section may be adjusted in response to receiving a user input that changes the brightness setting for a certain ambient light level.

Abstract: A method for controlling characteristics of an electronic device based on ambient light levels is provided. In one embodiment, the method includes receiving light at an ambient light sensor of a device and measuring components, such as color components, of the visible light. The component levels may be weighted differently by factors that vary based on the intensity of the light received by the ambient light sensor. Also, the brightness level of a light source in the device or color output of the device may be controlled based on the weighted component levels. Additional methods, systems, and devices relating to control of an electronic device based on sensed ambient light are also disclosed.

Abstract: Embodiments of a system that includes one or more integrated circuits are described. During operation, the system may determine an intensity setting of the light source based on at least a portion of a video image, such as the portion of the transformed video image that includes spatially varying visual information in the video image. Moreover, the system may modify the video image so that a product of the intensity setting and a transmittance associated with the modified video image approximately equals a product of a previous intensity setting and a transmittance associated with the video image. For example, the modification may include scaling brightness values in the transformed video image. Next, the system may identify a region in the video image in which the scaling of the brightness values results in a visual artifact associated with reduced contrast. For example, the region may include a bright region surrounded by a darker region.

Abstract: The present disclosure relates to the use of inverse dithering of color or grey-scale images. In certain embodiments, an image area may be selected having a center pixel. A predictive value of the image area may be found by averaging the values of the pixels in the image area. This predictive value may be compared to the center pixel's real value. A difference between the real value and the predictive value may then be found and used to diffuse the energy removed from the center pixel to neighboring pixels. By inverse dithering images using an energy diffusion approach, the images may be presented as having a more visually appealing display, even in situations where the images may undergo further edge enhancements.

Abstract: Systems and methods are disclosed to enable the creation and the display of spatio-temporal dithered images. Embodiments include techniques that use color-shifting and luminance. In one embodiment, adjacent pixels are color-shifted with respect to each other and the color values of the adjacent pixels are temporally alternated with color values of pixels in the group. In another embodiment, the luminance of group of adjacent pixels is determined and the luminance of the group is made more homogenous spatially and temporally by distributing color variations over a larger number of pixels so as to reduce the luminance difference between the pixel with the least luminance and the pixel with the greatest luminance. Individual color components (e.g., red, green, blue) may also be separated and used so that the color-shifts associated with each color component may be simultaneously present in different pixels.

Abstract: Embodiments of a system that includes one or more integrated circuits are described. During operation, the system transforms the video image from an initial brightness domain to a linear brightness domain, which includes a range of brightness values corresponding to substantially equidistant adjacent radiant-power values in a displayed video image. In this linear brightness domain, the system may determine an intensity setting of the light source based on at least a portion of the transformed video image, such as the portion of the transformed video image that includes spatially varying visual information in the video image. Moreover, the system may modify the transformed video image so that a product of the intensity setting and a transmittance associated with the modified video image approximately equals a product of a previous intensity setting and a transmittance associated with the video image. For example, the modification may include changing brightness values in the transformed video image.

Abstract: Methods and devices are provided for controlling the brightness of a display for an electronic device based on ambient light conditions. In one embodiment, an electronic device may employ one or more brightness adjustment profiles for changing the brightness of a display based on ambient light levels and/or the angle of incidence of one or more ambient light sources. In certain embodiments, one or more ambient light sensors may be designed to perceive the ambient light level differently based on the angle of incidence of a light source. The perceived ambient light level may then be used to adjust the display brightness based on the one or more brightness adjustment profiles. In other embodiments, one or more ambient light sensors may be designed to detect the angle of incidence of an ambient light source. In these embodiments, the detected angle and the ambient light level may be used to adjust the display brightness.

Abstract: Systems, methods, and devices are provided for histogram generation and evaluation used in adjusting the power consumed by a backlight of an electronic display. One such method involves generating a pixel brightness histogram of an image frame passing through a pixel pipeline in a nonlinear space. One or more pixel brightness values from the histogram may be selected before being converted from the nonlinear space into a linear space. A tone mapping function and backlight intensity are determined based at least in part on the one or more pixel brightness values in the linear space. The resulting tone mapping function is converted to the nonlinear space and applied to the image frame or a subsequent image frame in the pixel pipeline. The pixels of the image frame to which the nondistorting portion of the tone mapping function is applied may appear substantially undistorted despite a reduction in backlight intensity.

Abstract: Systems, methods, and devices are provided for temporal filtering of tone mapping slopes used in adjusting the power consumed by a backlight of an electronic display. One such method involves computing a current first target slope of an intermediate tone mapping function based at least in part on characteristics of a current image frame and temporally filtering the current first target slope to obtain a current first transition slope. A current backlight intensity of the display and a current final tone mapping function may be determined based at least in part on the current first transition slope. The current final tone mapping function may be applied to the current image frame or a subsequent image frame.

Abstract: Systems, methods, and devices are provided for generating a tone mapping function used in adjusting the power consumed by a backlight of an electronic display. One such method includes sampling an image frame in framebuffer space and generating a tone mapping function in linear space. The tone mapping function may have at least two portions: a nondistorting portion that does not to distort pixels to which it applies when an intensity of a backlight of the electronic display is modified and a distorting portion that does distort pixels to which it applies when the intensity of the backlight is modified. Thereafter, the intensity of the backlight may be modified based at least in part on the nondistorting portion of the tone mapping function, the tone mapping function converted to framebuffer space, and the tone mapping function applied to the image frame or a subsequent image frame.