Archived posting to the Leica Users Group, 1999/10/12
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]WOW! We are impressed..... > ---------- > From: Jim Brick[SMTP:jim@brick.org] > Reply To: leica-users@mejac.palo-alto.ca.us > Sent: Tuesday, October 12, 1999 9:51 PM > To: leica-users@mejac.palo-alto.ca.us; leica-users@mejac.palo-alto.ca.us > Subject: [Leica] Re: pixel count, was Paperless??? > > Hi Shawn, > > Almost all correct. But it takes four (4) physical pixels to represent one > (1) image pixel. It's 4:1, not 3:1. So it's worse than many folks think. > > The reason is that sensors use a Bayer pattern, which takes into account > the most prevalent color mix that mother nature gave us. The pixel > sequence > is: > > RGRGRGRGRGRGRGRGRGRGRGRG > GBGBGBGBGBGBGBGBGBGBGBGB > RGRGRGRGRGRGRGRGRGRGRGRG > GBGBGBGBGBGBGBGBGBGBGBGB > > There are two green pixels for every one red and one blue pixel. They are > in a quadrant contained in two pixel rows. > > RG RG RG > GB GB GB > > So real resolution is one quarter of stated resolution. > > Jim > > At 12:34 AM 10/13/99 -0400, Shawn London wrote: > > > >One additional thing to consider here is that while a digital camera can > >consider itself a "2 megapixel" camera as many do these days, it is > >important to keep in mind that this is the device's CCD pixel density, > not > >the actual number of pixels in the final image file that it generates. > This > >is due to the fact that three imaging sensing pixels in a CCD are needed > to > >determine the color of a single pixel in the final image. The bottom line > is > >that there is only 1/3 the effective resolution in a CCD that its stated > >resolution would suggest. The rest of the data is interpolated to give > you > >an image file of the stated resolution (i.e. 1800x1600). > > >