Fokuser i etterkant

Ved Stanford University har forskerne utviklet en teknologi de kaller "Plenoptic Camera", som gjør det mulig å bestemme fokuspunkt og dybdeskarphet etter at bildet er tatt.

Teknikken gjør det mulig velge fokuspunktet og dybdeskarpheten i etterbehandlingen av bildet. Dermed blir det strengt tatt ikke nødvendig å fokusere bildet. På sikt vil dette kunne føre til langt raskere kamera, samt lavere produksjonskostnader på grunn av færre bevegelige deler.

This figure illustrate how views from the top, center, and bottom of the camera aperture can be obtained by electroniclly selecting the appropriate pixels from the plenoptic image.

Consider a camera with an aperture that activate only one pixel behind each lenticular element. As this aperture is translated, it activate different pixels. For example, forming an image from the lower pixels correspond to a top view. Likewise, forming images from the central pixels or the upper pixels correspond to center and bottom views, respectively.

Thus by using a wide open aperture, all views are captured simulatneously by the plenoptic image without any movement of the aperture or camera components. The optics of the plenoptic camera and the arrangement of pixels allow these views to be electronically decoded for recovery of 3D scene structure.

Details of the optics can be better understood with a movie ( mov, mov.gz ) illustrating the mapping of the pixels to the effective aperture.

• Focusing after the shot, the plenoptic camera: Digital Photography Review.
• "Light Field Photography with a Hand-Held Plenoptic Camera"
• "Refocusable Photograph Gallery" (movies)
• Rapport som forklarer teknologien (1 MB PDF)