Claims
- 1. In a digital camera comprising an electronic image recorder for recording an overall image signal, said image recorder comprising a regular arrangement of pixels, each pixel having three light-sensitive image cells each covered by one of three different color filters, and each pixel thus generating three mutually independent image signals assigned to one of three colors, wherein said overall image signal comprises a color saturation, a method for modifying said color saturation, said method comprising the steps of:
recording said mutually independent image signals in each of said pixels in a logarithmically compressed format, determining a logarithmically compressed brightness signal from said mutually independent image signals as an arithmetic mean of said mutually independent image signals, selecting at least one of said mutually independent image signals, and transforming said at least one independent image signal selected as a function of said logarithmically compressed brightness signal.
- 2. The method of claim 1, wherein said steps of selecting and transforming are executed for all mutually independent image signals of all pixels.
- 3. The method of claim 1, wherein said step of transforming is executed according to the equation
- 4. A method of modifying a color saturation in an overall image signal comprising mutually independent image signals assigned to one of three different colors, said method comprising the steps of:
providing said mutually independent image signals in a logarithmically compressed format, determining a logarithmically compressed brightness signal from said mutually independent image signals, selecting the independent image signal of at least one color, and transforming said independent image signal selected as a function of said logarithmically compressed brightness signal.
- 5. The method of claim 4, wherein said logarithmically compressed brightness signal is determined as an arithmetic mean of said mutually independent image signals of the pixel.
- 6. The method of claim 4, wherein said step of transforming is executed according to the equation
- 7. The method of claim 6, wherein said saturation factor αc is selected in dependence on a contrast factor γ by which, in the context of a γ correction step, the logarithmically compressed image signals are multiplied before the transformation step.
- 8. The method of claim 7, wherein said saturation factor αc decreases as said contrast factor γ increases.
- 9. The method of claim 8, wherein said saturation factor αc is selected on the basis of a piecewise linear and monotonically falling function describing the relationship between said saturation factor αc and said contrast factor γ.
- 10. The method of claim 6, wherein said saturation factor αc is selected depending on said logarithmically compressed brightness signal.
- 11. The method of claim 10, wherein said saturation factor αc is selected proportional to said logarithmically compressed brightness signal.
- 12. A digital camera comprising:
an electronic image recorder for recording an overall image signal having a color saturation, said image recorder comprising a regular arrangement of pixels, each pixel having three light-sensitive image cells covered by one of three different color filters, and each pixel thus generating three mutually independent image signals assigned to one of three colors, said pixels generating said mutually independent image signals in a logarithmically compressed format, and a saturation stage for modifying said color saturation, said saturation stage comprising a digital signal processor adapted to execute a method comprising the steps of:
determining a logarithmically compressed brightness signal from said mutually independent image signals, selecting the independent image signal for at least one color, and transforming said independent image signal selected as a function of said logarithmically compressed brightness signal.
- 13. A saturation stage for modifying a color saturation of an overall image signal comprising logarithmically compressed and mutually independent image signals assigned to one of three different colors, said saturation stage comprising a computer adapted to execute a method comprising the steps of:
determining a logarithmically compressed brightness signal from said mutually independent image signals, selecting the logarithmically compressed independent image signal for at least one color, and transforming said logarithmically compressed independent image signal determined as a function of said logarithmically compressed brightness signal.
- 14. The saturation stage of claim 13, wherein said computer is programmed to execute said step of transforming according to the equation
Priority Claims (1)
Number |
Date |
Country |
Kind |
100 00 779.1 |
Jan 2000 |
DE |
|
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation of copending international patent application PCT/EP00/12571 filed on Dec. 12, 2000 and designating the U.S., which claims priority from German patent applications DE 100 00 779.1, filed on Jan. 11, 2000.
Continuations (1)
|
Number |
Date |
Country |
Parent |
PCT/EP00/12571 |
Dec 2000 |
US |
Child |
10192304 |
Jul 2002 |
US |