Multispectral image capture device comprising a filter wheel
AssigneeAirbus Defence and Space GmbH
InventorPierre-Luc Georgy
Life of this patent
Estimating the term…
Abstract
A multispectral image capture device includes a filter wheel (4) and an image sensor. The filters (41-46) are located close to a focusing plane of a light beam used to form the images, and at least one of the filters is more angularly narrow than the optical field of the image sensor. The production of the filter is thereby facilitated. Advantageously, the filters are closer to one another in the wheel such that multiple filters are in the optical field of the sensor simultaneously. Each multispectral image can be captured more quickly than when each filter covers the entire optical field of the sensor.
Claims18
Multispectral image capture device (10), comprising:
- an image-forming optical system (1, 2), suitable for forming an image in a focal plane (FP);
- at least one two-dimensional image sensor (3), comprising a photosensitive surface limited by a peripheral contour (C3), and situated in the focal plane (FP);
- a wheel (4) that comprises a plurality of spectral filters (41-46), arranged in order to keep said filters parallel and close to the focal plane (FP) or to an intermediate image plane (IP) of the image-forming optical system (1, 2);
- and
- a drive system (5), arranged in order to rotate the wheel (4) about an axis of rotation (A-A) so as to bring each of the filters (41-46) into the light beam (L);
- in which at least one of the filters (41-46), called filter having a narrow angular sector, has an angular extension that is less than an angular extension of the photosensitive surface of the image sensor (3) when the filters are close to the focal plane (FP), or that is less than an angular extension of a portion (30) of the intermediate image plane (IP) that is optically conjugated with the entire photosensitive surface by a re-imaging part (2) of the image-forming optical system, the angular extensions being measured with respect to the axis of rotation (A-A) of the wheel (4),
- the drive system (5) being adapted in order to rotate the wheel (4) continuously while several images are captured successively by the image sensor (3);
- wherein the image sensor (3) comprises a plurality of separate photosensitive pixels (31) adapted in order to operate each according to an acquisition sequence that comprises successively at least one phase of signal accumulation and one phase of reading an accumulated signal;
- and the angular extension of the filter having a narrow angular sector is greater than an angle of rotation described by the wheel (4) during a sum of a total period of the acquisition sequence and a period of an additional accumulation phase.
Dependencies are inferred from the claim text.