Flash light compensation system for digital camera system
View Patent ↗The invention refers to a flash light compensation system and corresponding method for digital camera systems, wherein a luminance compensation is carried out on an image of a scene ( 3 ) picked-up by an image sensor ( 1 ), on the basis of a respective intensity field measured by a plurality of sensors ( 4, 5 ), when the scene is illuminated by flash light emitted by a flash device ( 2 ). Depending upon the output signals of the plurality of sensors a depth field of the scene is estimated, and this estimation provides a basis for the luminance adjustment on the scene picked up as an image while illuminated by the flash device. The system and method is suitable for effectively reducing the problem of unevenly distributed lighting on a picked-up image of the scene.
1. A flash light compensation system for a digital camera system, comprising:
a camera including an image sensor for picking-up an image of a scene to be photographed,
a flash device for emitting light to said scene, and
a plurality of sensors for measuring the respective intensity field and generating corresponding output signals,
a depth-field estimator for estimating, based on the output signals of said plurality of sensors, a depth field of the scene,
a compensator unit for providing a luminance adjustment on the scene picked-up by the image sensor and illuminated by the flash device, based on the depth field estimation by the depth-field estimator, wherein the compensator unit is further configured to receive a flash input indicative of a flash intensity or a flash focus,
a display screen to display a preview of the image of the scene to be photographed, and
a user interface to receive a user input and to communicate the user input to the compensator unit to adjust an amount of compensation of the luminance adjustment after the preview is displayed.
2. System according to claim 1 , wherein said plurality of sensors are arranged spaced from each other.
3. System according to claim 2 , wherein said plurality of sensors are arranged spaced from each other according to a predetermined distance.
4. System according to claim 1 , wherein said plurality of sensors comprise a first sensor and a second sensor which are arranged at opposing edges of said camera.
5. System according to claim 1 , wherein said plurality of sensors are adapted for simultaneously performing measurement of said respective intensity field.
6. System according to claim 1 , wherein said plurality of sensors are adapted for performing measurement of the background distance versus the foreground distance of the scene.
7. System according to claim 1 , wherein said compensator unit is adapted for controlling an increase of intensities in regions of the scene far from said camera and a lowering of intensities in regions of the scene closer to said camera.
8. System according to claim 1 , further comprising a noise reduction unit adapted to provide a spatial filtering operation to predetermined regions of the scene.
9. System according to claim 8 , wherein said noise reduction unit is adapted to provide said spatial filtering operation to darkened portions of the scene.
10. A digital camera system, comprising:
a flash light compensation system according to claim 1 .
11. A system according to claim 9 , wherein the user interface is further configured to receive a second user input and to communicate the second user input to the noise reduction unit to adjust an amount of smoothness applied to imaged scene.
12. A system according to claim 1 , wherein the compensator unit is further configured to receive a lens input indicative of a lens type of a lens used to photograph the scene.
13. A system according to claim 1 , wherein the compensator unit is further configured to receive an exposure input indicative of at least one exposure condition of the imaged scene.
14. A method of controlling a flash light compensation system of a digital camera system, comprising the steps of:
picking-up an image of a scene to be photographed while emitting flash light to said scene,
measuring a respective intensity field by a plurality of sensors and generating corresponding output signals,
estimating, based on said output signals, a depth field of said scene,
receiving a lens input indicative of a lens type of a lens used to photograph the scene
displaying a preview of the image of the scene to be photographed to a user,
receiving a user input from the user to set a luminance adjustment for the scene after the preview is displayed,
communicating the user input to set the luminance adjustment for the scene, and
providing the luminance adjustment on the scene illuminated by the flash light based on the depth field estimated and the user input from the user.
15. A method according to claim 14 , further comprising:
receiving a second user input, and
adjusting an amount of smoothness applied to an imaged scene based on the second user input.
16. A method according to claim 14 , further comprising receiving a flash input indicative of a flash intensity or a flash focus.
17. A method according to claim 14 , further comprising receiving an exposure input indicative of at least one exposure condition of the imaged scene.