Deeper depth of field for video
View Patent ↗A digital camera apparatus has a sensing surface that captures images at a first resolution. A derivative of the captured image is displayed at a viewfinder or stored in a memory, after encoding, with a second, generally lower resolution. The resolutions are related by a downscale ratio. A method for digitally imaging a scene includes providing an imaging lens and a digital image sensing surface such as a CCD sensing surface, and changing a focusing of the lens with respect to the sensing surface in correspondence with a variance of a parameter that relates a captured image at the sensing surface and another image deriving from the captured image. Preferably, the variance of the parameter is the downscale ratio. The focusing of the lens with respect to the sensing surface may be changed by changing the physical distance or by changing a shape of the lens, for example. Apparatus and computer program products are also detailed.
1. A method for digitally imaging a scene comprising:
providing an imaging lens and a digital image sensing surface for receiving light through the lens;
changing an optical distance between the lens and sensing surface such that a hyperfocal distance varies with a downscale ratio that relates a captured image at the sensing surface and another image deriving from the captured image.
2. The method of claim 1 , wherein the another image comprises an image displayed at a visual display interface.
3. The method of claim 2 wherein the visual display interface comprises a viewfinder.
4. The method of claim 1 , wherein the another image comprises an image encoded and stored on a digital storage medium.
5. The method of claim 1 for digitally displaying a video scene.
6. The method of claim 1 wherein changing the optical distance between the lens and the sensing surface comprises moving the lens relative to the sensing surface.
7. The method of claim 1 wherein changing the optical distance between the lens and the sensing surface comprises changing a shape of the lens.
8. An apparatus comprising:
a digital sensing surface;
an optical lens;
means for changing an optical distance between the optical lens and the digital sensing surface;
a computer readable memory for storing data indicative of a relation between the optical distance and downscale ratio in which, for at least some downscale ratios, the optical distance corresponds to a hyperfocal distance; and
a processor coupled to the memory, to the means for changing the optical distance, and to the digital sensing surface, said processor for operating the means for changing an optical distance to vary the optical distance according to the stored relation.
9. The apparatus of claim 8 , wherein the means for changing an optical distance comprises mechanical means for moving the lens relative to the sensing surface along the optical axis.
10. The apparatus of claim 8 , wherein the means for changing an optical distance comprises a voltage source and leads for applying a voltage to a liquid lens that changes shape responsive to an applied voltage.
11. The apparatus of claim 8 , further comprising a display interface coupled to the processor for displaying an image deriving from the sensing surface according to the downscaling ratio.
12. The apparatus of claim 11 wherein the display interface comprises a viewfinder.
13. The apparatus of claim 8 , wherein the memory is further for storing an encoding algorithm; and the processor is further for executing the encoding algorithm on an output of the digital sensing surface and storing said algorithm in said memory.
14. A mobile station comprising:
a digital sensing surface;
an optical lens;
means for changing an optical distance between the optical lens and the digital sensing surface;
a computer readable memory for storing data indicative of a relation between the optical distance and downscale ratio; and
a processor coupled to each of the memory, the means for changing the optical distance, and the digital sensing surface, said processor for operating the digital sensing surface to capture a video image and for operating the means for changing an optical distance to vary the optical distance according to the stored relation.
15. A program of machine-readable instructions, tangibly embodied on an information bearing medium and executable by a digital data processor, to perform actions directed toward changing an optical distance between an optical lens and a sensing surface, the actions comprising:
correlating movement of a lens relative to a sensing surface of a digital image capturing component so as to vary a hyperfocal length with a downscale ratio that relates an image captured at the sensing surface and a derivative image deriving from the image captured at the sensing device.
16. The program of machine readable instructions of claim 15 , wherein the derivative image comprises an image displayed at a visual display interface.
17. The program of machine readable instructions of claim 15 , wherein the derivative image comprises a viewfinder.
18. The program of machine readable instructions of claim 15 , wherein the derivative image comprises an image encoded and stored on a digital storage medium.
19. The program of machine readable instructions of claim 15 , wherein movement of the lens relative to the sensing surface is actuated by electronically changing a shape of the lens.
20. The program of machine readable instructions of claim 15 , executable in conjunction with optical zooming of the lens during capture of a video image at the sensing surface.