Image signal processing apparatus, image display apparatus, multidisplay apparatus, and chromaticity adjustment method for use in the multidisplay apparatus

An image display apparatus, comprising:

• an image signal preprocessing means for preprocessing a color image signal;
• and
• an image display means for displaying images in accordance with the preprocessed color image signal, wherein
• the image signal preprocessing means includes
• an image signal receiving means for receiving the color image signal,
• a gamma correction means for performing a gamma correction on the received color image signal to produce gamma corrected color image signal values;
• and
• a chromaticity adjustment means for performing a calculation using the gamma corrected color image signal values so as to adjust the chromaticity of an image to be displayed by the image display apparatus for each of primary colors red, green, and blue, separately.

A multidisplay apparatus for allowing a plurality of image display units to display a plurality of images side by side on a screen, comprising:

• an image distribution means for generating, from a received color image signal, a plurality of color image signals for a plurality of images to be displayed respectively by the plurality of image display units;
• and
• a plurality of chromaticity adjustment means which respectively correspond to the plurality of image display units and each performs a calculation using signal values of one of the plurality of color image signals to be input to a corresponding image display unit and adjusts the chromaticity to a target chromaticity level for each of the primary colors red, green, and blue of an image to be displayed by the corresponding image display unit, wherein
• the target chromaticity level for each primary color is set to a value in chromaticity coordinates that is among coordinate values belonging to a common chromaticity range which is common to ranges of chromaticity that can be displayed by the plurality of image display units, and is closest to a standard chromaticity coordinate value for each primary color.

A chromaticity adjustment method for adjusting the chromaticity of images displayed by a multidisplay apparatus that allows a plurality of image display units to display a plurality of images side by side on a screen, the multidisplay apparatus including a plurality of chromaticity adjustment means which respectively correspond to the plurality of image display units and each receive a parameter, perform a calculation using signal values of a color image signal in accordance with the received parameter, and adjust the chromaticity of an image to be displayed by a corresponding image display unit for each of primary colors red, green, and blue, separately, the chromaticity adjustment method comprising:

• a first step for inputting an image signal to each image display unit for each of primary colors red, green, and blue, allowing each image display unit to display an image, and measuring the chromaticity and the brightness of the image displayed by each image display unit for each primary color;
• and
• a second step for determining, in accordance with measured values of the chromaticity and the brightness, the parameters to be respectively input to the plurality of chromaticity adjustment means so that chromaticity values of the images displayed by the plurality of image display units are substantially equal to each other for each primary color, wherein
• the second step includes:
• a first sub-step for obtaining, from chromaticity values for each primary color, ranges of chromaticity that can be displayed by the plurality of image display units;
• a second sub-step for obtaining a common chromaticity range which is common to the obtained ranges of chromaticity, and setting target chromaticity values for each of red, green, and blue out of values belonging to the common chromaticity range;
• and
• a third sub-step for determining the parameters so that chromaticity values of the images displayed by the plurality of image display units are substantially equal to the target chromaticity values for each of red, green, and blue.