Image processor, image display device, image processing method, and image display method

An image processor that corrects an image signal, the image processor comprising:

• a memory that stores an unextracted brightness component of the image signal;
• a signal extracting circuit that extracts a signal in a predetermined spatial frequency band from the unextracted brightness component of the image signal;
• a brightness component correction amount calculating section that receives the signal in the predetermined spatial frequency band extracted by the signal extracting circuit and that receives the unextracted brightness component of the image signal, the brightness component correction amount calculating section calculating an amount of correction of the unextracted brightness component of the image signal only for the signal in the predetermined spatial frequency band extracted by the signal extracting circuit;
• and
• a brightness component correcting section that receives the amount of correction calculated by the brightness component correction amount calculating section and the unextracted brightness component of the image signal and that corrects the unextracted brightness component of the image signal by using the amount of correction calculated by the brightness component correction amount calculating section,
• wherein the brightness component correction amount calculating section includes a brightness gain calculating circuit that receives the unextracted brightness component of the image signal directly from the memory, the brightness gain calculating circuit calculating a brightness gain corresponding to the level of the unextracted brightness component of the image signal,
• wherein the brightness component correction amount calculating section calculates the amount of correction of the unextracted brightness component on the basis of the signal in the predetermined spatial frequency band extracted by the signal extracting circuit and the brightness gain calculated by the brightness gain calculating circuit, and
• wherein the amount of correction in a region having a predetermined brightness level is larger than the amount of correction in another region.

An image processing method of correcting an image signal, the method comprising:

• extracting, by a signal extracting unit, a signal in a predetermined spatial frequency band from an unextracted brightness component of the image signal;
• calculating, by a brightness component correction amount calculating unit that receives the signal in the predetermined spatial frequency band extracted by the extracting step and that receives the unextracted brightness component of the image signal, an amount of correction of the unextracted brightness component of the image signal only for the signal in the predetermined spatial frequency band extracted by the extracting step;
• and
• correcting, by a brightness component correcting unit that receives the amount of correction calculated by the calculating step and that receives the unextracted brightness component of the image signal, the unextracted brightness component of the image signal by using the amount of correction calculated in the calculating of the amount of correction of the brightness component,
• wherein the calculating step includes calculating a brightness gain by a brightness gain calculating unit that receives the unextracted brightness component of the image signal directly from a memory that stores the unextracted brightness component of the image signal, the brightness gain corresponding to the level of the unextracted brightness component of the image signal, and
• wherein the calculating step is performed on the basis of the signal in the predetermined spatial frequency band extracted by the extracting step and the brightness gain calculated by the calculating step.

An image display method of displaying an image on the basis of an image signal, the method comprising:

• extracting, by a signal extracting unit, a signal in a predetermined spatial frequency band from an unextracted brightness component of the image signal;
• calculating, by a brightness component correction amount calculating unit that receives the signal in the predetermined spatial frequency band extracted by the extracting step and that receives the unextracted brightness component of the image signal, an amount of correction of the unextracted brightness component of the image signal only for the signal in the predetermined spatial frequency band extracted by the extracting step;
• correcting, by a brightness component correcting unit that receives the amount of correction calculated by the calculating step and that receives the unextracted brightness component of the image signal, the unextracted brightness component of the image signal by using the amount of correction calculated in the calculating of the amount of correction of the brightness component;
• and
• displaying, by an image display unit, an image on the basis of the image signal corrected in the correcting of the brightness component,
• wherein the calculating step includes calculating a brightness gain by a brightness gain calculating unit that receives the unextracted brightness component of the image signal directly from a memory that stores the unextracted brightness component of the image signal, the brightness gain corresponding to the level of the unextracted brightness component of the image signal, and
• wherein the calculating step is performed on the basis of the signal in the predetermined spatial frequency band extracted by the extracting step and the brightness gain calculated by the calculating step.

An image display method of displaying an image on the basis of an image signal, the method comprising:

• extracting, by a signal extracting unit, a signal in a predetermined spatial frequency band from an unextracted brightness component of the image signal;
• calculating, by a brightness component correction amount calculating unit that receives the signal in the predetermined spatial frequency band extracted by the extracting step and that receives the unextracted brightness component of the image signal, an amount of correction of the unextracted brightness component of the image signal in the predetermined spatial frequency band extracted by the extracting step;
• correcting, by a brightness component correcting unit that receives the amount of correction calculated by the calculating step and that receives the unextracted brightness component of the image signal, the unextracted brightness component of the image signal by using the amount of correction calculated in the calculating of the amount of correction of the brightness component;
• and
• displaying, by an image display unit, an image on the basis of the image signal corrected in the correcting of the brightness component,
• wherein the calculating step includes calculating a brightness gain by a brightness gain calculating unit that receives the unextracted brightness component of the image signal directly from a memory that stores the unextracted brightness component of the image signal, the brightness gain corresponding to the level of the unextracted brightness component of the image signal,
• wherein the calculating step is performed on the basis of the signal in the predetermined spatial frequency band extracted by the extracting step and the brightness gain calculated by the calculating step, and
• wherein the amount of correction in a region having a predetermined brightness level is larger than the amount of correction in another region.