Image processing device and image processing method

An image processing device comprising:

• a luminance modulator operable to receive a video input signal and operable to calculate a video output signal to be supplied to a display panel coupled;
• a backlight control gain adjustment unit operable to calculate a backlight control signal to be supplied to a backlight controller provided in the display panel;
• a peak value detector operable to calculate a peak value as a maximum luminance value in a prescribed region of the video input signal;
• a histogram detector operable to calculate frequency distribution about the luminance value of the video input signal in the prescribed region,
• wherein the luminance modulator converts a luminance value of the video input signal into a luminance value of the video output signal for every pixel, based on the peak value and the frequency distribution, and
• wherein the backlight control gain adjustment unit calculates the backlight control signal based on the peak value;
• a peak Automatic contrast level (ACL) control gain calculation unit;
• a pattern-adaptive gamma characteristic calculation unit;
• and
• a total control gain calculation unit,
• wherein the peak ACL control gain calculation unit calculates a peak ACL control gain with which the luminance of each pixel of the video input signal is amplified, based on a ratio of the peak value to the maximum possible value of the video output signal,
• wherein the pattern-adaptive gamma characteristic calculation unit calculates a luminance modulation gain with which the luminance of each pixel of the video input signal is modulated, based on the frequency distribution,
• wherein the total control gain calculation unit calculates a product of the peak ACL control gain and the luminance modulation gain as a total control gain,
• wherein the luminance modulator converts the luminance value of the video input signal into the luminance value of the video output signal for every pixel based on the total control gain,
• wherein the pattern-adaptive gamma characteristic calculation unit calculates the luminance modulation gain based on at least one of a first function, a second function, and a third function,
• wherein the first function has no point of inflection and enhances the luminance for every pixel of the video input signal,
• wherein the second function has one point of inflection and enhances the luminance about a high luminance pixel above a barycenter of the frequency distribution among the video input signal, and reduces the luminance about a low luminance pixel below the barycenter,
• wherein the third function linearizes the relation of a cumulative value of the frequency to a luminance value of the frequency distribution, and
• wherein the frequency distribution rate calculation unit derives the first function, the second function, and the third function in parallel, derives further a fourth function by weighting addition of the first function, the second function, and the third function, and supplies the fourth function to the pattern-adaptive gamma characteristic calculation unit, in lieu of the first function, the second function, and the third function.

An image processing device comprising:

• a luminance modulator operable to receive a video input signal and operable to calculate a video output signal to be supplied to a display panel coupled;
• a backlight control gain adjustment unit operable to calculate a backlight control signal to be supplied to a backlight controller provided in the display panel;
• a peak value detector operable to calculate a peak value as a maximum luminance value in a prescribed region of the video input signal;
• and
• a histogram detector operable to calculate frequency distribution about the luminance value of the video input signal in the prescribed region,
• wherein the luminance modulator converts a luminance value of the video input signal into a luminance value of the video output signal for every pixel, based on the peak value and the frequency distribution, and
• wherein the backlight control gain adjustment unit calculates the backlight control signal based on the peak value;
• a peak Automatic contrast level (ACL) control gain calculation unit;
• a pattern-adaptive gamma characteristic calculation unit;
• and
• a total control gain calculation unit,
• wherein the peak ACL control gain calculation unit calculates a peak ACL control gain with which the luminance of each pixel of the video input signal is amplified, based on a ratio of the peak value to the maximum possible value of the video output signal,
• wherein the pattern-adaptive gamma characteristic calculation unit calculates a luminance modulation gain with which the luminance of each pixel of the video input signal is modulated, based on the frequency distribution,
• wherein the total control gain calculation unit calculates a product of the peak ACL control gain and the luminance modulation gain as a total control gain,
• wherein the luminance modulator converts the luminance value of the video input signal into the luminance value of the video output signal for every pixel based on the total control gain,
• wherein the pattern-adaptive gamma characteristic calculation unit calculates the luminance modulation gain based on at least one of a first function, a second function, and a third function,
• wherein the first function has no point of inflection and enhances the luminance for every pixel of the video input signal,
• wherein the second function has one point of inflection and enhances the luminance about a high luminance pixel above a barycenter of the frequency distribution among the video input signal, and reduces the luminance about a low luminance pixel below the barycenter, and
• wherein the third function linearizes the relation of a cumulative value of the frequency to a luminance value of the frequency distribution, said image processing device further comprising:
• a frequency distribution rate calculation unit,
• wherein, when no localized distribution is observed in the frequency distribution, the frequency distribution rate calculation unit derives the first function and supplies it to the pattern-adaptive gamma characteristic calculation unit,
• wherein, when the frequency distribution is locally distributed at one place, the frequency distribution rate calculation unit derives the second function and supplies it to the pattern-adaptive gamma characteristic calculation unit,
• wherein, when the frequency distribution is locally distributed at several regions, the frequency distribution rate calculation unit derives the third function with which a gamma value is specified based on the cumulative value of the frequency in the frequency distribution, and supplies the third function to the pattern-adaptive gamma characteristic calculation unit, and
• wherein the frequency distribution rate calculation unit evaluates the feature of the video input signal, based on the weighted frequency distribution which is obtained by multiplying a pretreatment function specifying the weighting corresponding to the luminance value of the video input signal to the frequency distribution.

An image processing device comprising:

• a luminance modulator operable to receive a video input signal and operable to calculate a video output signal to be supplied to a display panel coupled;
• a backlight control gain adjustment unit operable to calculate a backlight control signal to be supplied to a backlight controller provided in the display panel;
• a peak value detector operable to calculate a peak value as a maximum luminance value of the video input signal in a prescribed region;
• a peak Automatic contrast level (ACL) control gain calculation unit operable to calculate a peak ACL control gain with which the luminance of each pixel of the video input signal is amplified, based on the ratio of the peak value to the maximum possible value of the video output signal;
• a gamma characteristic calculation unit operable to calculate a luminance modulation gain with which the luminance of each pixel of the video input signal is modulated;
• and
• a total control gain calculation unit operable to calculate the product of the peak ACL control gain and the luminance modulation gain as a total control gain,
• wherein the luminance modulator converts the luminance value of the video input signal into the luminance value of the video output signal for every pixel based on the total control gain, and
• wherein the backlight control gain adjustment unit calculates the backlight control signal based on the peak value.