PanoTools mailing list archive
|Date/Time:||19-Oct-2010 04:46:44 +0000|
|Subject:||Re: What's a Gigapixel?|
On Oct 18, 2010, at 7:31 PM, Christian Bloch wrote:
> Is it 1000 or 1024 Megapixel?
> Personally, I'm not afraid labeling a crisp and clear 500 Megapixel pano as Gigapixel, but I was just wondering what's the official definition.
It is really about resolution isn't it? - other than bragging rights about total pixels.
So maybe we should define it as a panorama, *or portion of a panorama*, that would have a billion pixels (more or less) if it were a complete equirectangular image. That would be 44,720 to 46,340 pixels wide, right?
There is usually no point in printing a gigapixel equirectangular in its entirety (or viewing nadir and zenith if interactive). So we don't want to exclude panoramas at that resolution which have been cropped to just the part with interest.
Put another way, a gigapixel-resolution panorama would have at least 128 pixels per angular degree at the equator. To be truly panoramic it would also have to cover a wide field of view, from a minimum 120° or 140° up to 360°.
As an example, a true gigapixel equirectangular, with 25% cropped off both top and bottom, ends up with half a gig of pixels. If cropped again to one half its original width it is only one quarter of a gig. But it has the same detail, and may be a stronger image if cropped judiciously. I would still consider it to be a gigapixel pano.
A definition such as this will be necessary for gigapixel categories in panoramic photography contests. It would be useful to reach a consensus before it becomes an issue.