Agilent Technologies, Inc.

Hewlett-packard Company

Robert W Jones

Xuemei Zhang

Izhak Baharav

Donald M Reid

An adaptive image tone mapping curve based on perceptual preference guidelines is generated as a sigmoidal function, in which the sigmoidal function parameters (slope and shift) are determined by original image statistics. Tone curves generated for different images each have a smooth sigmoidal shape, so that the tone mapping process does not change the image histogram shape drastically. The sigmoidal function has the form:where &#x3b1; is the slope parameter and &#x3b2; is the shift parameter. The input value x in the sigmoidal function varies in the range [0, 100], because the tone curve is generated on an L* scale, which has values from 0 to 100. The sigmoidal tone curve calculation can be implemented efficiently using simple arithmetic operations by pre-calculating and storing various factors used in the calculation of &#x3b1; and &#x3b2; and by pre-generating a pair of fixed tone curves with two extreme slopes and interpolating between the curves.

System and method for digital image tone mapping using an adaptive sigmoidal function based on perceptual preference guidelines

A technique for digitally capturing a high contrast color image involves simultaneously capturing image data from bright and dark areas using an image sensor with pixels of the same color that have different sensitivities to the bright and dark areas. The image data from the different sensitivity pixels is then used to generate a final image that includes features from both the bright and dark areas. An embodiment of a digital imaging system includes an image sensor with a first group of pixels that have a first sensitivity to a first color and a second group of pixels that have a second sensitivity to the same color. Image data that is captured by the two groups of pixels is brought to a common scale by a scaling unit before the image data is used to generate demosaiced image data. The scaled image data is used by a demosaic unit to determine intensity values for the first color at all of the pixel locations. Errors in the demosaiced intensity values that result from capturing the first color image data with pixels of two different sensitivities are corrected by an error correction unit to generate a final image that accurately depicts the original high contrast color image.

System and method for capturing color images that extends the dynamic range of an image sensor using first and second groups of pixels

A calculating device and related method for accessing and selecting among multiple key functions with a minimum of keystrokes. The keyboard includes menu keys corresponding to menu labels displayable on the display and a multi-function key having a primary function and a secondary function. Which of the key functions is selected depends on the duration of the key press. The calculating device executes the primary function if the key is pressed for a short time. However, if the key is pressed for longer than a given time period, the calculating device displays a set of menu labels and assigns a function associated with a displayed menu label to a menu key. If the key continues to be pressed, the display scrolls to show additional sets of menu labels. A menu function may then be selected by releasing the multi-function key and pressing the appropriate menu key.

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Corvallis, OR, United States of America

Robert W Jones