Monday, May 25, 2009

Options for when analog cameras die

If you read yesterday’s post, “Who cried when analog died?” you’ll have spent all night worrying about how you’re going to replace those older interlaced cameras with digital progressive scan models.

Well fear not, for I am going to provide you with a list of links for further reading.
First, for an in-depth look at the whole analog versus digital, interlaced versus progressive scan issue, here’s an excellent article culled from the NASA Tech Briefs web site: “
Interlaced Goes Digital: Combining Interlaced Sensors With a Digital Interface” (December 2008) The major points you’ll glean from the article (if not from the title,) are:

  • Interlaced sensors tend to be more sensitive to light than the equivalent progressive scan item. (Don’t ask me why, you’ll need a physicist for that.)

  • There are some interlaced digital cameras on the market, and you might want to consider these as replacements in aging systems.

One vendor of such cameras is Allied Vision Technology (AVT). They are one of the companies that are good about putting technical information on their web site, which is why I offer this link to a paper titled, “Interlaced goes Digital,” which discusses the merits of interlaced versions of their range of “Guppy” cameras.

Then, when you’re comfortable with the theory, I suggest you take a look at another AVT article, “Cotton Interlaced,” (May 2009) which describes a real analog to digital upgrade project. This was carried out by “Premier Evolvics,” an Indian machine vision integration company. I plan to take a closer look at this company in the near future, and will of course report back here on what I learn. In the meantime, you might be intrigued by these two pictures of the cotton fiber inspection system.

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