System and method for image luminance transformation

A method of converting an image to adjust overall brightness of the image when displayed, the method comprising the steps of:

• a) receiving image data defining the image, the image data including a plurality of original colors;
• b) transforming each of the plurality of colors to a corresponding one of a plurality of transformed colors, each of the plurality of transformed colors having a new luminance at least proximate a corresponding desired luminance;
• c) comparing the new luminance of each of the plurality of transformed colors to its corresponding desired luminance;
• d) selectively modifying any of the plurality of transformed colors that do not have the corresponding desired luminance to achieve the desired corresponding luminance, wherein the step of selectively modifying any of the plurality of transformed colors that do not have the corresponding desired luminance to achieve the desired corresponding luminance comprises modifying using a weighted sum of the transformed color and a brightest color;
• and
• e) displaying the image using the plurality of transformed colors as selectively modified.

A method of converting an image to adjust overall brightness of the image when displayed, the method comprising the steps of:

• a) receiving image data defining the image, the image data including a plurality of original colors;
• b) transforming each of the plurality of colors to a corresponding one of a plurality of transformed colors, each of the plurality of transformed colors having a new luminance at least proximate a corresponding desired luminance;
• c) selecting a desired luminance for each transformed color, wherein the desired luminance for each transformed color is calculated by subtracting an original luminance for a corresponding original color from a maximum luminance;
• d) comparing the new luminance of each of the plurality of transformed colors to its corresponding desired luminance;
• e) selectively modifying any of the plurality of transformed colors that do not have the corresponding desired luminance to achieve the desired corresponding luminance;
• and
• f) displaying the image using the plurality of transformed colors as selectively modified.

A program product comprising:

• a) an image conversion program for altering an image to adjust the overall brightness of the image when displayed, the image conversion program comprising:
• a luminance transformer, the luminance transformer receiving image data, the luminance transformer transforming each original color in the image data to a transformed color having a new luminance, the new luminance selected to be at least proximate to a desired luminance while maintaining hues of the original color;
• and
• a color adjuster, the color adjuster modifying the transformed color to achieve the desired luminance in the transformed color if the new luminance does not equal the desired luminance, and wherein the color adjuster modifies the transformed color using a weighted sum of the transformed color and a brightest color;
• and
• b) computer-readable signal bearing media bearing said image conversion program.

A program product comprising:

• a) an image conversion program for altering an image to adjust the overall brightness of the image when displayed, the image conversion program comprising:
• a luminance transformer, the luminance transformer receiving image data, the luminance transformer transforming each original color in the image data to a transformed color having a new luminance, the new luminance selected to be at least proximate to a desired luminance while maintaining hues of the original color, and wherein the desired luminance for each transformed color is calculated by subtracting an original luminance for a corresponding original color from a maximum luminance;
• and
• a color adjuster, the color adjuster modifying the transformed color to achieve the desired luminance in the transformed color if the new luminance does not equal the desired luminance;
• and
• b) computer-readable signal bearing media bearing said image conversion program.