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Blocking the lens, as the group has done, makes a tiny, fuzzy ring appear around an image. However, this ring is about a micrometer in diameter, and since most of the light sensors in cameras are only sensitive to a resolution of two micrometers, the ring is undetectable. "If you had a perfect detector with infinite resolution this would be a disaster," says Ford. "But it works well for the kind of sensors that we'd find for [digital cameras]."
The UCSD research takes advantage of a well-known optical system, says José Saisián, professor of optical sciences and astronomy at the University of Arizona, in Tucson, but he admits that the design is unique. "I think it has some merit," he says. "They took this idea, analyzed it well, and it can have some interesting applications."
Ford acknowledges that there were some drawbacks to the group's initial prototype. The first prototype had a limited depth of focus, for example, which meant that anything approximately two inches in front of or behind the focus point of the lens will appear blurry. However, he says, his team has explored different-shaped lenses that increase the depth of focus, and it has built successful camera prototypes. A second, smaller prototype, using a slice cut from a round lens, matched the depth of field of the conventional camera. Ford claims that the third generation imager, which is now being tested, will be even smaller.
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This document is part of the “How-To Guide for Most Common Measurements” centralized resource portal. This tutorial provides a detailed guide for measurement and device considerations to take temperature measurements using thermocouples. Get an introduction to thermocouples, which are inexpensive sensing devices widely used with PC-based data acquisition systems. Also review some specific thermocouple examples and learn how thermocouples work and ways to integrate them into a data acquisition measurement system.
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dickcaro
8 Comments
Good work but a waste of time
The answer to good pictures in cellphones is more pixels and digital zoom. The trend in semiconductors including image sensors is to higher density. Using this technology to get a 3:1 zoom is OK, but installing 8 megapixels and using a 3:1 digital zoom will soon be less expensive and better.
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omarg
2 Comments
Re: Good work but a waste of time
Digital zoom although a cheaper option has some serious drawbacks. Since it uses the image interpolation technology, there is a drastic reduction in image quality. Even the higher resolution cannot address this issue since the actual image layout captured by the image sensors, cannot be regained. Secondly, working with digital zoom makes the images more prone to blurring due to slight movement of the camera while capturing the image.
Hence this alternate design of the camera lens can offer better solutions to the cell phone industry.
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gaijin
1 Comment
Re: Good work but a waste of time
It think the previous comment about using say 8Mpix and digital zoom for 3 X was indicating that without interpolation this woudl lead to a theoretical resolution of 8 /sqrt 3 = 4.7Mpix.
So very nearly the same resolution as zooming a 5Mpix sensor 3X. But nothing physically moves.
It woudl not be more prone to hand shake effects than optical zoom, both magnify this.
However the effect that neither correspondant has mentioned is that smaller pixels collect less light. The low light performance of an 8Mpix sensor in the same optical format as an 5Mpix woudl be worse.
The same effect would be a problem with the research cited. The fact that 90% of light reflected off the top face may not make the image contrast look poor (although I find this difficult to believe), but it wodl most definitely affect the low light perfromance by a huge margin.
I don't think it is a waste of time, but there are still problems to solve.
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PeterPiper
1 Comment
Re: Good work but a waste of time
Using x3 digital zoom on an 8Mpixel sensor (3264 x 2448 say) you would get only 1/3^2 of the sensor resolution, so image size 1088 x 816. Zooming in to 4Mpixels only gives you x1.414 not x2, sorry (x2 would only give you a 2Mpixel image). You COULD zoom in further than 1 to 1, but you are not adding any new information, just adding more data points to a smaller and smaller raw image.
Futher to the point about reduced sensitivity, another effect of the smaller pixel pitch is the lens can't resolve to that level. You could use bigger pixels, but that is more Silicon, more money, longer focal length so larger lens and shorter depth of field. Yet another issue is reduced full well capacity (means the best noise level that can be achieved is limited, the reason why higher and higher pixel count cameras are getting more noisy....).
My question is, they say optical zoom. This needs a change in the characteristics of the optics, normally achieved by moving one of the lens elements. In this case, how is the 'zoom' actually achieved?
I have checked this, sorry for any errors (especially spelling!).
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