Color matching across multiple sensors in an optical system
Matching color information in an optical system can include splitting an image forming beam into a bright intensity beam and a dark intensity beam, detecting, using multiple sensors, a color value for a light component from the bright intensity beam and the dark intensity beam, determining color values for the remaining light components associated with the bright intensity beam and the dark intensity beam, and transforming the color values associated with the dark intensity beam to calibrate the color values of the dark intensity beam against the color values of the light intensity beam, the color values of the light intensity beam including color inaccuracies.
1. A method for generating a true color, high dynamic range (HDR) image, the method comprising:
splitting, using a beamsplitter in an optical system, an image forming beam into a first portion and a second portion;
capturing a first image from the first portion using a first sensor;
capturing a second image from the second portion using a second sensor;
introducing, using a processor in the optical system, imperfections associated with the second sensor into the first image to give a transformed first image;
combining the transformed first image with the second image to form an HDR image; and
removing the imperfections associated with the second sensor from the HDR image to thereby transform the HDR image into a true color HDR image.
2. The method of claim 1 , wherein the beamsplitter splits the beam asymmetrically such that the first portion is darker than the second portion and such that the first image is a dark version of the second image.
3. The method of claim 1 , wherein the beamsplitter comprises a 90:10 beamsplitter such that the second sensor receives approximately nine times as much light as the first sensor.
4. The method of claim 1 , wherein combining the transformed image with the second image to form the HDR image comprises:
identifying one or more saturated pixel values in the second image; and
replacing the saturated pixel values with replacement values determined by interpolating across corresponding pixels of the transformed image.
5. The method of claim 1 , wherein the processor is operable to
remove imperfections associated with the first sensor from the first image by pre-multiplying first RGB values with a matrix [C];
remove the imperfections associated with the second sensor from the second image by pre-multiplying second RGB values with a matrix [B].
6. The method of claim 5 , wherein the processor introduces the imperfections associated with the second sensor into the first image by pre-multiplying the first RGB values with [B]−1.
7. The method of claim 6 , further wherein, when the first RGB values are represented as the vector [R1] the processor introduces the imperfections by performing [C][B]−1[R1].
8. The method of claim 6 , wherein the processor represents RGB values in the HDR image as a vector [R′] and transforms the HDR image into the true color HDR image by performing [B][R′].
9. The method of claim 1 , wherein the processor removes imperfections associated with the first sensor and transforms the HDR image into the true color HDR image through the use of one or more look-up tables.
10. The method of claim 1 , wherein the processor is a field-programmable gate array or an application-specific integrated circuit.
11. The method of claim 1 , wherein the beamsplitter splits the beam asymmetrically such that the second portion is darker than the first portion and such that the second image is a dark version of the first image.