Apple Inc.

Spectral Edge Limited

Roberto Montagna

David R Pope

Graham D Finlayson

Muge Wang

Ilya Romanenko

An image processing circuit for multi-illumination white balance with thumbnail processing. The image processing circuit determines a set of initial weights for a source pixel in a thumbnail image by determining component values for multiple color channels of the source pixel. The image processing circuit determines a set of weights for the source pixel in a weight map for the thumbnail image. Each weight in the set of weights is determined based on corresponding initial weights from the set of initial weights. Each weight in the set of weights represents an intensity level of a respective chrominance class of multiple chrominance classes for the source pixel. The image processing circuit applies the set of weights to values of the color channels of the source pixel to generate color component values of the color channels of a target pixel in a target thumbnail image.

Multi-illumination white balance circuit with thumbnail image processing

One limitation of traditional imaging systems is that they are only programmed to correct for a single color of illuminant in a scene. In multi-illuminant scenes, the detected illuminant color may correspond to some mixture of scene illuminants. This may lead to incomplete color correction, wherein, e.g., the dominant illuminant is corrected for but the color cast caused by secondary illuminants is still visible, or an at least partially visible color cast remains from multiple of the scene illuminants. Thus, the techniques disclosed herein comprise: obtaining an image of a scene; generating an illumination map for the obtained image; dividing the values in the illumination map to determine a number of estimated illuminant regions, wherein each region corresponds to at least one estimated illuminant present in the captured scene; estimating a white point for each region; and applying white balancing operations, based on the estimated white points for each region.

Image white balance processing system and method

An image processing method, system and device are disclosed. In the method, sensor responses for an input image are estimated, the sensor responses including sensor responses for cone sensors including a first cone sensor set and a second, different, cone sensor set. In dependence on the sensor responses, a transform mapping for application to a source image is determined to generate a modified image.

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Cambridge, United Kingdom

Roberto Montagna