Patent ID: 11860309
Assignee: TRW LIMITED
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A 3D imaging system comprising:
a light source arranged to illuminate a scene with at least one optical pulse comprising light of at least two discrete wavelengths;
an optical detector comprising an array of detection elements; and
an optical modulator interposed in the optical path between the scene and the optical detector, the modulator being arranged to differentially amplitude modulate the two wavelengths in the reflected portion of the optical pulse as a function of time, wherein the optical modulator comprises a variable wavelength filter that in a first mode of operation differentially modulates the amplitude of the two wavelengths such that the first wavelength is increasingly attenuated over time and the second wavelength is not attenuated or is decreasingly attenuated over that time, the optical modulator in a second mode of operation differentially modulates the amplitude of the two wavelengths whereby the second wavelength is increasingly attenuated over time and the first wavelength is not attenuated or is decreasingly attenuated;
in which the detector captures a first image of the scene corresponding to the first set of pulses whereby for each pulse the modulator is operated in the first mode only, and in which the detector captures a second image of the scene corresponding to the second set of pulses whereby for each pulse the modulator is operated in the second mode only, and
in which the first image is captured at a different time to the second image to form a pair of images, and further comprising a signal processing circuit which determines the range of objects in the scene by comparing the colour value measured by each detector element in the array in the first image with the colour value measured by each of the corresponding detector elements in the array that form the second image.