PDF《PureView imaging technology》

?2012 Nokia

1 PureView imaging technology.

PureView imaging technology Written by Juha Alakarhu, Damian Dinning, and Eero Salmelin on behalf of many dedicated Nokia imaging experts ?2012 Nokia ?2012 Nokia

2 PureView imaging technology. This paper describes Nokia'

s new PureView Pro imaging technology as well as the product, Nokia

808 PureView, featuring it. The Nokia PureView Pro imaging technology is the combination of a large, super high resolution 41Mpix with high performance Carl Zeiss optics. The large sensor enables pixel oversampling, which will be explained in detail in this paper but in a nutshell it means the combination of many pixels into one perfect pixel. PureView imaging technology is the result of many years of research and development and the tangible fruits of this work are amazing image quality, lossless zoom, and superior low light performance. A revolution in imaging PureView Pro imaging technology doesn'

t represent a step change for camera smartphones performance, so much as a quantum leap forward. The first device to feature Nokia PureView Pro camera technology is the Nokia

808 PureView, which gives people the means to take better images and video footage than ever before. Nokia PureView Pro turns conventional thinking on its head. It dispenses with the usual scaling/ interpolation model of digital zoom used in virtually all smartphones, as well as optical zoom used in most digital cameras, where a series of lens elements moves back and forth to vary the magnification and field of view. Instead, we'

ve taken a completely new road. The result? Unprecedented camera control and versatility, combined with truly spectacular-quality images and video. Nokia

808 PureView sets new industry standards ― it will give you around 3x lossless zoom for stills, and 4x zoom in full HD 1080p. For 720p HD video, you'

re looking at 6x lossless zoom. And for nHD (640x360) video, an amazing 12x zoom! ?2012 Nokia

3 PureView imaging technology. So how is this possible? The starting point is a super-high-resolution sensor. This has an active area of

7728 x

5368 pixels, totalling over 41Mpix. Depending on the aspect ratio you choose, it will use

7728 x

4354 pixels for 16:9 images/videos, or

7152 x

5368 pixels for 4:3 images/videos as is shown in Figure 1. What happens next depends on the settings and whether or not you'

re using zoom. But to give you an idea, the default still image setting is 5Mpix at 16:9, and for video it'

s 1080p at 30fps. Using these settings, the zoom is around 3x for stills and 4x for video. Conventional zoom tends to scale up images from a relatively low resolution, resulting in poor image quality. We were convinced there must be a better way, and we found it. Always true to the image With the Nokia N8, we limited the digital zoom to just 2x to avoid too much compromise to image quality. But at the end of the day, this was still a conventional digital zoom. With the Nokia

808 PureView, zoom is handled completely differently ― like nothing that has gone before. We'

ve taken the radical decision not to use any upscaling whatsoever. There isn'

t even a setting for it. When you zoom with the Nokia

808 PureView, in effect you are just selecting the relevant area of the sensor. So with no zoom, the full area of the sensor corresponding to the aspect ratio is used. The limit of the zoom (regardless of the resolution setting for stills or video) is reached when the selected output resolution becomes the same as the input resolution. Figure 1. The image circle and the 16:9 and 4:3 image areas ?2012 Nokia