eugene kowaluk
http://www.tpd.tno.nl/smartsite966.html
The 2.5 gigapixel photo
TNO has produced the largest digital panoramic photo in the world. So, what do we mean by large? After all, modern consumer cameras can easily take a picture with 5 million pixels. Well, we are talking about a photo of completely different dimensions. One with 2.5 billion pixels - that's 500 times more pixels. If this photo were printed, it would measure 6.67 m by 2.67 m (300 dpi). The photograph shows Delft and its surroundings in the autumn of 2004. It was taken the top of the Electrical Engineering faculty of Delft University, at a height of about 100 m, by TNO.
The 2.5 gigapixel image is a composition of images rather than a single image. TNO developed a sophisticated approach to merge the many images - all 600 of them. The photos were taken automatically using a modern consumer camera and a powerful 400 mm lens. The camera was positioned automatically using a computer-controlled pan-tilt unit. Each of the 600 photos overlaps, an arrangement that ensured very accurate positioning and enabled us to stitch the images automatically into one giant image of 78,797 by 31,565 pixels. The most difficult tasks were processing these large images and comparing the overlapping images.
All 600 photos were taken over a period of 1 hour and 15 minutes. Taking a single photo and moving the camera to a new position took approximately seven seconds. Thanks to the long 'exposure time', some interesting artefacts are visible at the edges of the various photos. They include a parked car that seems to merge into a bus and a walking torso.
After the photographic session, considerable effort was required to calculate the final result. It took about 24 hours to compare the overlapping photos and optimise them. Stitching the photos into one image required the capacity of 5 high-end pcs for three full days.
The final result allows the viewer to zoom in on the city of Delft and its surroundings at a resolution never seen before.
• Final image dimensions: 78.797 x 31.565 pixels
• Number of pixels in final image: 2,487,227,305 (2.5 gigapixel)
• Final image file format: 24-bit colour bitmap
• Final image file size: 7.5 GBytes
• Number of source images: 600
• Number of pixels in source images: 3,537,408,000 (600 images * 3008*1960)
• Lens focal length: 400 mm (equivalent to 600 mm on a 35 mm camera)
• Aperture: F22, Shutter speed: 1/100, ISO: 125
• Horizontal field of view of final image: 93 degrees
• Time required to capture component images: 1 hour and 12 minutes
• Time required to match overlapping images: 20 hours
• Time required to optimise project: 4 hours
• Time required to compose the image: 3 full days using 5 high-end pcs
• Time required to blend seams / correct misalignments / finalise image: 2 days
