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Apple eyeing ways to improve iOS device cameras

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Two Apple patents at the US Patent & Trademark Office show that Apple is working on methods of further improving the cameras in its OS device.

Patent 20110292246 involves automatic tone mapping curve generation based on dynamically stretched image histogram distribution. An apparatus, method, computer useable medium, and processor programmed to automatically generate tone mapping curves in a digital camera based on image metadata are described.

“Rather than having a static tone mapping curve for all images, the curve can be varied automatically based on, e.g., the brightness histogram of the image. In one embodiment, a certain percentage of the least bright pixels and a certain percentage of the brightest pixels can be disregarded, while the remaining pixels can be linearly stretched to encompass the original range of brightness values. Based on the distribution of the resultant stretched brightness histogram, slopes for the low end (S.sub.0) and high end (S.sub.1) of the tone mapping curve can be independently determined, and the tone mapping curve can be automatically generated.

“The improved, automatically generated tone mapping curve may be able to lift shadows more aggressively and/or increase the dynamic range of the image. Ralph Brunner is the inventor.

Patent 20110293259 is for scene adaptive auto exposure. Per the patent systems, methods, and a computer readable medium for an improved automatic exposure algorithm attempt to classify an image into a particular “scene category,” and, based on the determined scene category, meter the scene according to a generated metering weighting matrix. In one embodiment, the average luminance is calculated for a central exposure metering region of the image and a plurality of peripheral exposure metering regions surrounding the central exposure metering region. Based on comparisons of the average luminance values of the peripheral exposure regions to the average luminance of the central exposure region, a target metering weighting matrix may be generated.

In another embodiment, the scene category corresponds to a predetermined metering weighting matrix. In video applications, it may be desirable to reduce oscillations in metering parameter values to limit any visually jarring effects on the camera’s preview screen by only adjusting metering parameter values when predetermined criteria are met. The inventors are Frank Doepke and Ralph Brunner.

— Dennis Sellers

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