Dynamic backlight adaptation using selective filtering

A method for determining an intensity setting of a light source, comprising:

• calculating a brightness metric associated with a given video image in a sequence of video images;
• identifying a subset of the given video image based on the brightness metric, wherein the subset of the given video image includes spatially varying visual information in the given video image;
• determining the intensity setting of the light source based on a first portion of the brightness metric associated with the subset of the given video image, wherein the light source is configured to illuminate a display that is configured to display the sequence of video images;
• and
• filtering a change in the intensity setting of the light source relative to a previous intensity setting associated with at least a previous video image in the sequence of video images if the change is less than a first predetermined value.

A computer-program product for use in conjunction with a computer system, the computer-program product comprising a computer-readable storage medium and a computer-program mechanism embedded therein for determining an intensity setting of a light source, the computer-program mechanism comprising:

• instructions for calculating a brightness metric associated with a given video image in a sequence of video images;
• instructions for identifying a subset of the given video image based on the brightness metric, wherein the subset of the given video image includes spatially varying visual information in the given video image;
• instructions for determining the intensity setting of the light source based on a first portion of the brightness metric associated with the subset of the given video image, wherein the light source is configured to illuminate a display that is configured to display the sequence of video images;
• and
• instructions for filtering a change in the intensity setting of the light source relative to a previous intensity setting associated with at least a previous video image in the sequence of video images if the change is less than a first predetermined value.

An integrated circuit, comprising one or more sub-circuits, wherein the one or more sub-circuits are configured to:

• calculate a brightness metric associated with a given video image in a sequence of video images;
• identify a subset of the given video image based on the brightness metric, wherein the subset of the given video image includes spatially varying visual information in the given video image;
• determine the intensity setting of the light source based on a first portion of the brightness metric associated with the subset of the given video image, wherein the light source is configured to illuminate a display that is configured to display the sequence of video images;
• and
• filter a change in the intensity setting of the light source relative to a previous intensity setting associated with at least a previous video image in the sequence of video images if the change is less than a first predetermined value.

An integrated circuit, comprising:

• an input interface configured to receive video signals associated with a sequence of video images and a brightness setting of a light source which is configured to illuminate a display that is configured to display the video images;
• an extraction circuit electrically coupled to the input interface, the extraction circuit operative to calculate a brightness metric associated with a given video image in the sequence of video images based on the received video signals;
• an analysis circuit electrically coupled to the extraction circuit, the analysis circuit configured to analyze the brightness metric to identify a subset of the given video image, wherein the subset of the given video image includes spatially varying visual information in the given video image;
• an intensity circuit electrically coupled to the analysis circuit, the intensity circuit configured to determine an intensity setting of the light source based on the brightness setting and a first portion of the brightness metric associated with the subset of the given video image;
• a filter electrically coupled to the intensity circuit, the filter configured to filter a change in the intensity setting of the light source relative to a previous intensity setting associated with at least a previous video image in the sequence of video images if the change is less than a first predetermined value;
• and
• an output interface electrically coupled to the filter, wherein the output interface is configured to output the intensity setting of the light source for the given video image.

A method for determining an intensity setting of a light source, comprising:

• receiving a sequence of video images, wherein a given video image in the sequence, when displayed, comprises a picture portion and the non-picture portion, the picture portion having a histogram of brightness values;
• determining the intensity setting of the light source on an image-by-image basis based on the histogram, wherein the light source is configured to illuminate a display that is configured to display the sequence of video images;
• and
• selectively filtering changes in the intensity setting of the light source, wherein the selective filtering is based on a magnitude of a given change in the intensity setting from a previous video image to a current video image.

A computer system to determine an intensity setting of a light source, comprising:

• a processor;
• memory;
• a program module, wherein the program module is stored in the memory and configurable to be executed by the processor, the program module comprising:
• instructions for receiving a sequence of video images, wherein a given video image in the sequence, when displayed, comprises a picture portion and the non-picture portion, the picture portion having a histogram of brightness values;
• instructions for determining the intensity setting of the light source on an image-by-image basis based on the histogram, wherein the light source is configured to illuminate a display that is configured to display the sequence of video images;
• and
• instructions for selectively filtering changes in the intensity setting of the light source, wherein the selective filtering is based on a magnitude of a given change in the intensity setting from a previous video image to a current video image.

A computer system configured to execute instructions to determine an intensity setting of a light source, comprising:

• a processor;
• a memory;
• an instruction fetch unit within the processor configured to fetch:
• instructions for receiving a sequence of video images, wherein a given video image in the sequence, when displayed, comprises a picture portion and the non-picture portion, the picture portion having a histogram of brightness values;
• instructions for determining the intensity setting of the light source on an image-by-image basis based on the histogram, wherein the light source is configured to illuminate a display that is configured to display the sequence of video images;
• and
• instructions for selectively filtering changes in the intensity setting of the light source, wherein the selective filtering is based on a magnitude of a given change in the intensity setting from a previous video image to a current video image;
• and
• an execution unit within the processor configured to execute the instructions for receiving the sequence of video images, the instructions for determining the intensity setting of the light source, and instructions for selectively filtering the change in the intensity setting.

A portable device, comprising:

• a display;
• a light source configured to output light based on an intensity setting;
• an attenuation mechanism configured to modulate the output light incident on the display, wherein the display is configured to display a sequence of video images;
• and
• one or more integrated circuits, wherein the one or more integrated circuits include:
• an input interface configured to receive video signals associated with the sequence of video images and a brightness setting of a light source;
• an extraction circuit electrically coupled to the input interface, the extraction circuit operative to calculate a brightness metric associated with a given video image in the sequence of video images based on the received video signals;
• an analysis circuit electrically coupled to the extraction circuit, the analysis circuit configured to analyze the brightness metric to identify a subset of the given video image, wherein the subset of the given video image includes spatially varying visual information in the given video image;
• an intensity circuit electrically coupled to the analysis circuit, the intensity circuit configured to determine an intensity setting of the light source based on the brightness setting and a first portion of the brightness metric associated with the subset of the given video image;
• a filter electrically coupled to the intensity circuit, the filter configured to filter a change in the intensity setting of the light source relative to a previous intensity setting associated with at least a previous video image in the sequence of video images if the change is less than a first predetermined value;
• and
• an output interface electrically coupled to the filter, the output interface configured to output the intensity setting of the light source for the given video image.