Rendering of high dynamic range images
AssigneeCanon Kabushiki Kaisha
InventorSharon A. Henley
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Abstract
White balance normalization of a high dynamic range image is performed by identifying a first image adaptation point for a relatively lighter portion of the image and a second image adaptation point for a relatively darker portion of the image. A first white point adjustment for the lighter portion of the image is performed using the first image adaptation point and a second white point adjustment for the darker portion of the image is performed using the second image adaptation point. Thus, multiple illumination sources can be taken into account in rendering a high dynamic range image, providing a more visually appealing rendered image.
Claims19
A method for processing high dynamic range image data which includes pixels whose values have a high dynamic range, so as to obtain counterpart image data which is renderable, the method comprising:
- using computer to perform the following steps:
- classifying each pixel of the high dynamic range image data into one of at least two different portions which include a relatively lighter portion and a relatively darker portion;
- identifying an image adaptation point for each of said different portions, said identifying step including the steps of identifying a first image adaptation point for the lighter portion and identifying a second image adaptation point for the darker portion;
- and
- performing white point adjustment for the value of each pixel in each of said different portions by using the corresponding image adaptation point for each said portion, said step of performing white point adjustment including the steps of performing a first white point adjustment for the values of pixels of the lighter portion using the first image adaptation point and performing a second white point adjustment for the values of the pixels of the darker portion using the second image adaptation point.
An apparatus for processing high dynamic range image data which includes pixels whose values have a high dynamic range, so as to obtain counterpart image data which is renderable, the apparatus comprising:
- classifying means for classifying each pixel of the high dynamic range image data into one of two different portions which include a relatively lighter portion and a relatively darker portion;
- an identification means for identifying an image adaptation point for each of said different portions, said identification means including means for identifying a first image adaptation point for the lighter portion and for identifying a second image adaptation point for the darker portion;
- and
- a white point adjustment means for performing white point adjustment for the value of each pixel in each of said different portions by using the corresponding image adaptation point for each said portion, said white point adjustment means including means for performing a first white point adjustment for the values of the pixels of the lighter portion using the first image adaptation point and for performing a second white point adjustment for the values of the pixels of the darker portion using the second image adaptation point.
An apparatus for processing high dynamic range image data which includes pixels whose values have a high dynamic range, so as to obtain counterpart image data which is renderable, the apparatus comprising:
- a classifying unit adapted to classify each pixel of the high dynamic range image data into one of at least two different portions which include a relatively lighter portion and a relatively darker portion;
- an identifying unit adapted to identify an image adaptation point for each of said different portions, said identifying step including the steps of identifying a first image adaptation point for the lighter portion and identifying a second image adaptation point for the darker portion;
- and
- a performing unit adapted to perform white point adjustment for the value of each pixel in each of said different portions by using the corresponding image adaptation point for each said portion, wherein said performing unit performs white point adjustment including the steps of performing a first white point adjustment for the values of the pixels of the lighter portion using the first image adaptation point and performs a second white point adjustment for the values of the pixels of the darker portion using the second image adaptation point.
Dependencies are inferred from the claim text.