DERIVATION OF AN ELECTROMAGNETIC SPECTRUM FROM A MULTI-STIMULUS COLOR VALUE FOR SIMULATING A CAMERA

1 . A method for generating synthetic camera data, the method comprising:

rendering, by a computer system, an image of a virtual scene and storing color information of a surface element of the virtual scene in the form of color space coordinates of a multi-stimulus color space;

assigning, by the computer system, to the surface element, a number of base functions which each describe a relative wavelength distribution of a light component emitted from the surface element;

modeling, by the computer system, a spectral radiance of the light emitted from the surface element as a linear combination of the base functions;

deriving, by the computer system, scaling factors of the base functions in the linear combination by arithmetically combining the spectral radiance with a color space coordinate from the color information of the surface element and a color matching function associated with the color space coordinate;

calculating, by the computer system, the spectral radiance by inserting the scaling factors; and

generating, by the computer system, the synthetic camera data by processing the spectral radiance in a camera simulation of a camera located in the virtual scene.

2 . The method according to claim 1 , wherein one of the base functions takes into account a spectral distribution of an illumination of the surface element and a reflection spectrum of the surface element.

3 . The method according to claim 2 , wherein a material attribute is assigned to the surface element, and the reflection spectrum is assigned to the material attribute.

4 . The method according to claim 1 , further comprising:

pre-calculating integrals to be solved to derive the scaling factors; and

starting a scene simulation of an evolution of the virtual scene over time after completion of the pre-calculation of the integrals, the scene simulation including a repetition of the rendering, the assigning, the modeling, the deriving, the calculating, and the generating;

wherein, in each cycle, the image of the virtual scene depicts a current state of the virtual scene, and the synthetic camera data is generated in each cycle using the pre-calculated integrals.

5 . The method according to claim 1 , further comprising:

calculating the color space coordinates taking into account a spatial orientation of the surface element in relation to the camera.

6 . The method according to claim 5 , wherein calculating the color space coordinates takes into account an angle between a straight line connecting the camera to the surface element and a surface normal of the surface element.

7 . The method according to claim 1 , wherein the spectral radiance is calculated in such a way that the spectral radiance includes wavelengths outside the visible spectral range.

8 . The method according to claim 7 , wherein the spectral radiance includes wavelengths below 380 nanometers or above 780 nanometers.

9 . The method according to claim 1 , wherein the synthetic camera data is generated as synthetic camera raw data, taking into account a quantum efficiency of a simulated image sensor of the camera.

10 . The method according to claim 1 , further comprising:

reading and processing, by a component of an electronic system configured for processing the camera data, the synthetic camera data for training the electronic system or for evaluating a response of the electronic system to the synthetic camera data.

11 . The method according to claim 10 , wherein the spectral radiance is calculated in such a way that the spectral radiance includes wavelengths outside the visible spectral range;

wherein the electronic system is an assistance system configured to analyze camera data from a camera directed at a person in order to monitor state of the person, the camera being capable of detecting wavelengths outside the visible spectral range; and

wherein the virtual scene includes a virtual representation of the person, and the image of the virtual scene includes an image of the person.

12 . The method according to claim 11 , wherein the camera is directed at the person while the person is operating a vehicle or a machine.

13 . The method according to claim 11 , wherein one of the base functions takes into account a spectral distribution of an illumination of the surface element and a reflection spectrum of the surface element; and

wherein the spectral distribution of the illumination simulates an infrared or ultraviolet illumination of the operating person.

14 . A non-transitory computer-readable medium having processor-executable instructions stored thereon for generating synthetic camera data, wherein the processor-executable instructions, when executed, facilitate performance of the following by a computer system:

rendering an image of a virtual scene and storing color information of a surface element of the virtual scene in the form of color space coordinates of a multi-stimulus color space;

assigning, to the surface element, a number of base functions which each describe a relative wavelength distribution of a light component emitted from the surface element;

modeling a spectral radiance of the light emitted from the surface element as a linear combination of the base functions;

deriving scaling factors of the base functions in the linear combination by arithmetically combining the spectral radiance with a color space coordinate from the color information of the surface element and a color matching function associated with the color space coordinate;

calculating the spectral radiance by inserting the scaling factors; and

generating the synthetic camera data by processing the spectral radiance in a camera simulation of a camera located in the virtual scene.

15 . A computer system, comprising:

at least one processor configured to:

render an image of a virtual scene and storing color information of a surface element of the virtual scene in the form of color space coordinates of a multi-stimulus color space;

assign, to the surface element, a number of base functions which each describe a relative wavelength distribution of a light component emitted from the surface element;

model a spectral radiance of the light emitted from the surface element as a linear combination of the base functions;

derive scaling factors of the base functions in the linear combination by arithmetically combining the spectral radiance with a color space coordinate from the color information of the surface element and a color matching function associated with the color space coordinate;

calculate the spectral radiance by inserting the scaling factors; and

generate the synthetic camera data by processing the spectral radiance in a camera simulation of a camera located in the virtual scene; and

an interface configured to provide the generated synthetic camera data to at least one component of an electronic system configured for processing camera data.