Process and device for the video recording of an illuminated field
For the video recording of a field illuminated by a lamp, especially a surgical lamp, where at least one light beam for illuminating the field emerges from a light exit area of a lamp housing in the direction of a predetermined housing axis, the optical axis of a video camera mounted with freedom to swivel a certain distance away from the exit point of the light beam is shifted automatically by a positioning element until the axis at least approximately intersects the light beam in the area of the illuminated field. The positioning element is driven by signals from a control unit. The video camera is preferably shifted in a stepwise manner. The distance to the illuminated field is determined by the fine focusing of the camera by the autofocus function, and then signals are transmitted from the control unit to the positioning element of the camera to compensate for the parallax between the optical axis of the camera and the light beam or beams emerging from the lamp.
1. A process for video recording a field illuminated by a lamp, comprising the step of:
directing at least one light beam for illuminating the field from at least one light exit area of a lamp housing toward a predetermined housing axis;
automatically adjusting the optical axis of a video camera, which is mounted on a bracket at a specified distance from the light exit with freedom to pivot the camera about a tilt axis, by a positioning element until the camera's optical axis intersects the at least one light beam in the area of the illuminated field; and
determining a required adjustment distance by first panning the camera across an entire adjustment range and then pivoting the camera to a position of maximum image brightness.
2. A process according to claim 1 , including driving the positioning element with signals from a control unit.
3. A process according to claim 2 , including determining the distance to the illuminated field by a fine adjustment of camera focus aided by an autofocus function of the video camera, and sending signals from the control unit to the positioning element of the camera to compensate for parallax between the optical axis of the camera and the light beam.
4. A process according to claim 3 , including using a zoom lens of the camera to enlarge the illuminated field to a maximum extent before activating the autofocus function of the video camera.
5. A process according to claim 1 , including adjusting the video camera relative to the predetermined housing axis until the optical axis of the camera at least approximately intersects the predetermined housing axis.
6. A process according to claim 1 , including pivoting the video camera in a stepwise manner.
7. A process according to claim 1 , including iteratively correcting the alignment of the optical axis of the camera.
8. A lamp, comprising:
at least one lamp housing;
a light source arranged in the housing so that at least one light beam emerges in a direction of a predetermined axis to illuminate a field;
a video camera arranged in the housing at a set distance away from one of an exit point of the light beam and the predetermined axis, the video camera having an optical axis and a positioning element operative to automatically shift the optical axis of the camera with respect to the at least one light beam or with respect to the predetermined axis of the lamp housing until the optical axis of the camera intersects the illuminated field;
a control unit operative to drive the positioning element of the video camera, the control unit being responsive to driving signals which depend on orientation of the video camera with respect to the predetermined axis of the lamp housing or of the light beam; and
an angle sensor operatively arranged to generate the driving signals, the sensor being operative to detect the orientation of the optical axis in space and the orientation of the lamp housing, of the predetermined axis, or of the light beam.
9. A lamp according to claim 8 , and further comprising a photosensor to generator a driving signal for the control unit.