Lens shading correction
View Patent ↗A method including using an optical image stabilization function in an imaging apparatus comprising a lens and an image sensor; acquiring system change information, the system change information concerning changes that affect optical path through the lens to the image sensor during capturing of an image through the lens; adjusting a lens shading correction function on the basis of the acquired system change information; and applying the adjusted lens shading correction function to image data representing the captured image.
1. A method comprising:
using an optical image stabilization function in an imaging apparatus comprising a lens and an image sensor;
acquiring system change information, the system change information concerning changes that affect optical path through the lens to the image sensor during capturing of an image through the lens;
adjusting a lens shading correction function on the basis of the acquired system change information; and
applying the adjusted lens shading correction function to image data representing the captured image,
wherein adjusting the lens shading correction function is performed by:
determining a plurality of intermediate positions for the captured image on the basis of the system change information, the system change information comprising more than one piece of system change information;
selecting one or more reference correction tables for the intermediate positions;
generating an intermediate shading correction table for the intermediate positions on the basis of the one or more reference correction tables; and
generating an adjusted shading correction table on the basis of the intermediate shading correction tables.
2. The method of claim 1 , wherein the system change information comprises information about position of the lens in relation to the image sensor.
3. The method of claim 1 , wherein the system change information comprises one or more of the following: lens position information, image sensor position information, tilting angle information, information about lens properties and control information causing changes in optical path through the lens to the image sensor.
4. The method of claim 1 , further comprising acquiring the system change information in metadata attached to the image data representing the captured image.
5. The method of claim 1 , further comprising acquiring the system change information by reading it from a stabilization unit controlling the optical image stabilization.
6. The method of claim 1 , wherein adjusting the lens shading correction function is performed by:
calculating an average position for the captured image on the basis of the system change information;
generating an adjusted shading correction table by shifting a default correction table by a difference between the calculated average position and a default position of the default correction table.
7. The method of claim 1 , further comprising:
using different reference correction tables for at least some of the intermediate positions.
8. A method comprising:
using an optical image stabilization function in an imaging apparatus comprising a lens and an image sensor;
acquiring system change information, the system change information concerning changes that affect optical path through the lens to the image sensor during capturing of an image through the lens;
adjusting a lens shading correction function on the basis of the acquired system change information; and
applying the adjusted lens shading correction function to image data representing the captured image,
wherein adjusting the lens shading correction function is performed by:
determining an average position for the captured image on the basis of the system change information;
selecting one or more reference correction tables for the average position; and
generating an adjusted shading correction table on the basis of the one or more reference correction tables.
9. An apparatus comprising:
a lens and an image sensor configured to capture images and to provide image data representing captured images;
a stabilization unit configured to control optical path through the lens to the image sensor during capturing of images through the lens to provide optical image stabilization;
a processing unit configured to cause the apparatus to perform
acquiring system change information, the system change information concerning changes that affect the optical path through the lens to the image sensor during capturing of an image through the lens;
adjusting a lens shading correction function on the basis of the acquired system change information; and
applying the adjusted lens shading correction function to the image data representing the captured image,
wherein the processing unit is configured to cause the apparatus to perform adjusting the lens shading correction function by:
determining a plurality of intermediate positions for the captured image on the basis of the system change information, the system change information comprising more than one piece of system change information;
selecting one or more reference correction tables for the intermediate positions;
generating an intermediate shading correction table for the intermediate positions on the basis of the one or more reference correction tables; and
generating an adjusted shading correction table on the basis of the intermediate shading correction tables.
10. The apparatus of claim 9 , wherein the system change information comprises information about position of the lens in relation to the image sensor.
11. The apparatus of claim 9 , wherein the processing unit is configured to cause the apparatus to perform adjusting the lens shading correction function by:
calculating an average position for the captured image on the basis of the system change information;
generating an adjusted shading correction table by shifting a default correction table by a difference between the calculated average position and a default position of the default correction table.
12. The apparatus of claim 9 , further comprising:
using different reference correction tables for at least some of the intermediate positions.
13. An apparatus comprising:
a lens and an image sensor configured to capture images and to provide image data representing captured images;
a stabilization unit configured to control optical path through the lens to the image sensor during capturing of images through the lens to provide optical image stabilization;
a processing unit configured to cause the apparatus to perform
acquiring system change information, the system change information concerning changes that affect the optical path through the lens to the image sensor during capturing of an image through the lens;
adjusting a lens shading correction function on the basis of the acquired system change information; and
applying the adjusted lens shading correction function to the image data representing the captured image,
wherein the processing unit is configured to cause the apparatus to perform adjusting the lens shading correction function by:
determining an average position for the captured image on the basis of the system change information;
selecting one or more reference correction tables for the average position; and
generating an adjusted shading correction table on the basis of the one or more reference correction tables.
14. A non-transitory computer readable medium embodying a computer program comprising computer executable program code which, when executed by at least one processor of an apparatus, causes the apparatus to perform:
acquiring system change information, the system change information concerning changes that affect optical path through a lens to an image sensor during capturing of an image through the lens;
receiving image data representing the image captured through the lens;
adjusting a lens shading correction function on the basis of the acquired system change information; and
applying the adjusted lens shading correction function to the image data,
wherein the computer executable program code causes the apparatus to perform adjusting the lens shading correction function by:
determining a plurality of intermediate positions for the captured image on the basis of the system change information, the system change information comprising more than one piece of system change information;
selecting one or more reference correction tables for the intermediate positions;
generating an intermediate shading correction table for the intermediate positions on the basis of the one or more reference correction tables; and
generating an adjusted shading correction table on the basis of the intermediate shading correction tables.
15. A non-transitory computer readable medium embodying a computer program comprising computer executable program code which, when executed by at least one processor of an apparatus, causes the apparatus to perform:
acquiring system change information, the system change information concerning changes that affect optical path through a lens to an image sensor during capturing of an image through the lens;
receiving image data representing the image captured through the lens;
adjusting a lens shading correction function on the basis of the acquired system change information; and
applying the adjusted lens shading correction function to the image data,
wherein the computer executable program code causes the apparatus to perform adjusting the lens shading correction function by:
determining an average position for the captured image on the basis of the system change information;
selecting one or more reference correction tables for the average position; and
generating an adjusted shading correction table on the basis of the one or more reference correction tables.