How many pixels in a digital camera should be used to analyse one particle or character

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Jim 2011-5-20

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采纳的回答： Jan

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Answer 1

Jan 2011-5-20

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What exactly is a "pixel in a digital camera"? You have to consider, that most digital cameras use different subpixels for different wavelength. Therefore the number of mega-pixel written on the camera is a artificial number only. And the actual resolution can differ from this mea-pixel-number remarkably.

What is a "particle" and a "character"? And what exactly means "analyse"?

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Walter Roberson 2011-5-20

http://en.wikipedia.org/wiki/Image_sensor#Color_separation

Jan 2011-5-20

@Vivek: This depends on the object. It would be very helpful, if you explain any details. I have a camera with 0.001k-pixels to measure the brightness of a distinct area in front of my old manually controlled chemo-mechanic-camera. For this task 1 pixel is sufficient.

At work I have to identify reflective markers with a diameter of 9mm in a distance of 10m with an location error of 1mm. Then there cannot be enough efficient megas of pixels.

If you want to identify an ice bear in a snow storm, the number of pixels is less important than the accuracy for differentiating colors.

"Identify an object" is too general to be useful for a matching answer.

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Answer 2

Walter Roberson 2011-5-20

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When analyzing an object (or character), you will have a minimum number of pixels needed to distinguish a feature of interest from other kinds of features. The number depends upon what you are looking for. The number of pixels needed to analyze a character in the "Latin Alphabet" (such as is used by English) is less than the number of pixels needed to analyze a Chinese character.

In my workplace, we would prefer to use images that exceeded 2048 pixels by 2048 pixels to analyze objects, but we find that in practice our current analysis algorithms cannot handle more than about 350 pixels per side in "real (enough) time".