Image signal processor that reduces a flicker component of an image signal depending on a level change between continuous frames
Provided is an image signal processor, including: an integrator configured to integrate each frame of an image signal; a first flicker corrector configured to extract a flicker component from the integrated value obtained by the integrator, the flicker component depending on a frequency of a light source, and to reduce a flicker component from the integrated value sequentially; and a second flicker corrector configured to generate a reference image without a flicker component based on the correction result of the integrated value corrected by the first flicker corrector, and to correct a flicker of the image signal based on the reference image.
1. An image signal processor, comprising:
circuitry configured to
integrate each frame of an image signal;
extract a flicker component from integrated value obtained by the circuitry, the flicker component depending on a frequency of a light source;
reduce a flicker component from the integrated value sequentially;
generate a reference image without a flicker component based on a correction result of the integrated value corrected by the circuitry;
correct a flicker of the image signal based on the reference image;
detect a level change between continuous frames, which are continuous in time direction;
store integrated values of a predetermined number of frames, the predetermined number being determined depending on a power-source frequency and a frame rate of the light source;
in case that the level change is not detected, calculate an average of integrated values of a predetermined number of latest frames stored in the circuitry to thereby generate the reference image; and
in case that the level change is detected, correct a flicker of the image signal based on the integrated value of only present image output from the circuitry as the reference image.
2. The image signal processor according to claim 1 , wherein
the circuitry is configured to detect the level change based on the integrated value corrected by the circuitry.
3. An image signal processor, comprising:
circuitry configured to
integrate each line of an image signal;
extract a flicker component from integrated value of each line obtained by the circuitry, the flicker component depending on a frequency of a light source;
reduce a flicker component from the integrated value of each line sequentially;
generate a reference image without a flicker component based on a correction result of the integrated value of each line corrected by the circuitry;
correct a flicker of the image signal based on the reference image;
detect a level change between continuous frames, which are continuous in time direction;
store integrated values of a predetermined number of frames, the predetermined number being determined depending on a power-source frequency and a frame rate of the light source;
in case that the level change is not detected, calculate an average of integrated values of a predetermined number of latest frames stored in the circuitry to thereby generate the reference image; and
in case that the level change is detected, correct a flicker of the image signal based on the integrated value of only present image output from the circuitry as the reference image.
4. An image signal processing method, comprising:
integrating, using circuitry, each frame of an image signal;
extracting, using the circuitry, a flicker component from integrated value obtained by the circuitry, the flicker component depending on a frequency of a light source;
reducing a flicker component from the integrated value sequentially;
generating, using the circuitry, a reference image without a flicker component based on a correction result of the integrated value corrected by the circuitry;
correcting a flicker of the image signal based on the reference image;
detecting a level change between continuous frames, which are continuous in time direction;
storing integrated values of a predetermined number of frames, the predetermined number being determined depending on a power-source frequency and a frame rate of the light source;
in case that the level change is not detected, calculating an average of integrated values of a predetermined number of latest frames stored in the circuitry to thereby generate the reference image; and
in case that the level change is detected, correcting a flicker of the image signal based on the integrated value of only present image output from the circuitry as the reference image.
5. An image signal processing method, comprising:
integrating, using circuitry, each line of an image signal;
extracting, using the circuitry, a flicker component from integrated value of each line obtained by the circuitry, the flicker component depending on a frequency of a light source;
reducing a flicker component from the integrated value of each line sequentially;
generating, using the circuitry, a reference image without a flicker component based on a correction result of the integrated value of each line corrected by the circuitry;
correcting a flicker of the image signal based on the reference image;
detecting a level change between continuous frames, which are continuous in time direction;
storing integrated values of a predetermined number of frames, the predetermined number being determined depending on a power-source frequency and a frame rate of the light source;
in case that the level change is not detected, calculating an average of integrated values of a predetermined number of latest frames stored in the circuitry to thereby generate the reference image; and
in case that the level change is detected, correcting a flicker of the image signal based on the integrated value of only present image output from the circuitry as the reference image.
6. A non-transitory computer readable medium including executable instructions, which when executed by a computer cause the computer to:
integrate each frame of an image signal;
extract a flicker component from integrated value obtained by the computer, the flicker component depending on a frequency of a light source;
reduce a flicker component from the integrated value sequentially;
generate a reference image without a flicker component based on a correction result of the integrated value corrected by the computer;
correct a flicker of the image signal based on the reference image;
detect a level change between continuous frames, which are continuous in time direction;
store integrated values of a predetermined number of frames, the predetermined number being determined depending on a power-source frequency and a frame rate of the light source;
in case that the level change is not detected, calculate an average of integrated values of a predetermined number of latest frames stored in the computer to thereby generate the reference image; and
in case that the level change is detected, correct a flicker of the image signal based on the integrated value of only present image output from the computer as the reference image.
7. A non-transitory computer readable medium including executable instructions, which when executed by a computer cause the computer to:
integrate each line of an image signal;
extract a flicker component from integrated value of each line obtained by the computer, the flicker component depending on a frequency of a light source;
reduce a flicker component from the integrated value of each line sequentially;
generate a reference image without a flicker component based on a correction result of the integrated value of each line corrected by computer
correct a flicker of the image signal based on the reference image;
detect a level change between continuous frames, which are continuous in time direction;
store integrated values of a predetermined number of frames, the predetermined number being determined depending on a power-source frequency and a frame rate of the light source;
in case that the level change is not detected, calculate an average of integrated values of a predetermined number of latest frames stored in the computer to thereby generate the reference image; and
in case that the level change is detected, correct a flicker of the image signal based on the integrated value of only present image output from the computer as the reference image.