Slashdot Mirror
Wavy Lenses Extend Depth of Field in Digital Imaging
genegeek writes "On Feb 25 CDM Optics was awarded a patent for a new digital imaging system utilizing "Wavefront Coding" that produces images with 10-fold the depth of field of conventional lenses. The image itself is blurred until processed. Image examples are here."
Basically what this is saying is that if I go out and get a new whiz-bang camera with this funky new lens, I will be able to take a picture almost as good as the pictures I take with my 30 year old Cannon AE-1, and not have the leeway of doing photo processing tricks in the darkroom.
Personally, I will stick to analog photography.
You say you want a revolution....
Yes. Even with the new lenses, they didn't see the Slashdot Effect coming. :)
They did, but didn't have time to process it so it was too blurred to make out :)
That wouldn't take long to saturate the processor. If it were flat html with images, it would just max out the network.
I hope the heatsinks work!
I couldn't help but think back to the problem with the Hubble Space Telescope, wherein after the launch they discovered that the mirror had not been properly ground to specification.
"Provided by the management for your protection."
Ah yes, I know this system well. I did my master's research in extended depth-of-field optics and came across this research which pretty much blew away what I was working on.
Here's a bit of background: in photography or laser scanning (point-by-point photography, basically), you always have a trade-off between depth-of-field and aperture size (as any photographer knows). Bigger aperture means shallow depth-of-field. However, a smaller aperture means lots of wasted light (imagine closing the aperture in your camera), and this means longer exposure times, and more importantly more NOISE in your images. This is true for digital, film, or photodetector.
So the "holy grail" is to keep the aperture open but still have high depth-of-field. This system depends on changing the phase of the light, instead of the amplitude (which is what you do when you stop down a lens to a smaller aperture). That way, no light energy is blocked and wasted.
Since the phase is changed, the resulting image on the CCD or film is fuzzy and has to be "decoded". You can think of it as "encoding" the wavefront in a special way that preserves the depth of field, capturing the image, and then "decoding" it into a sharp picture. It is really amazing. I hope it shows up in consumer cameras someday, it could completely change consumer photography since most "snapshot photographers" don't care about depth of field or all that stuff. It will also be great for medical and industrial imaging.
My system was sort of a hybrid between shading the aperture (instead of a sudden stopping of light, it gradually goes to black at the edge) and phase changes. Lots of people have been working on this problem over the years, but these guys really stripped the problem down to the essence and came up with a highly optimized solution.
Just because the base image quality may not be better (for 8x10 and larger from a 35mm sized camera, digital is so much better, but I like analog for 3X5 snapshots) doesn't mean the tricks and effects are neccessarily better.
Photoshop is great software, but no matter how much I try, basic manipulation (on b&w images particularly), especially brightness/contrast adjustment and dodging/burning, always gives me much better results under an enlarger. Same for exposure effects; Photoshop's solarize filter is good, but there's just some intangible warmth and...analog-ness to a well-solarized paper print. Maybe it's just the random scatter and size of the grain of film against the gridded regularity of the digital images, or the slight variation in quality across the print (not imperfect, but not...digitally homogenous), but for purely aesthetic ends, I have to go with film and paper.
Facts do not cease to exist because they are ignored. - Aldous Huxley
And I'm always leary of adopting a new technology that is monopolized by a single provider.
"It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
A story...on Slashdot...about a patent...that's legitimate?
Does anybody remember the deep focus cinematography of Gregg Toland? How were those shots done?
If you post it, they will read.
I'm suprised, the USPTO actually managed to issue a patent for something new and innovative and unique, rather than for something thats been common practice for a few years.
If I have been able to see further than others, it is because I bought a pair of binoculars.
I don't get the sense that you've ever used a good digital camera.
I've blown 6MP images up to 20"x30". They look great. Good enough that people gush about how great they look when they buy them from us, at least. While I don't have access to an 11MP camera, I can't imagine that 30"x40" would be too much of a stretch.
Keep in mind that I'm talking about images from a $5000 camera, not a piece-o'-crap point-and-shoot.
ZFS: because love is never having to say fsck
There are at least two experienced photographers (Rob Galbraith and Michael Reichmann) who feel that the 11-megapixel Canon EOS-1Ds delivers images with detail exceeding that of 35mm and approaching (in some cases besting) medium format film. They've published some very interesting comparisons:
s p? cid=7-4833-4853
a s/ 1ds/1ds-field.shtml
http://www.robgalbraith.com/bins/content_page.a
http://www.luminous-landscape.com/reviews/camer
This may just change someone's opinon on how digital compares to film. I know it made me rethink the "conventional wisdom" that many more pixels are needed to reproduce film detail.
Cheers,
Jeremy
Yeah, but the text is real sharp, isn't it?
Sometimes boldness is in fashion. Sometimes only the brave will be bold.
The real problem there is dynamic range. Photoshop still works in 8 bits per channel, which is clearly not enough for any sort of exposure / brightness / contrast control. You need at least 16 bits per channel, preferably 32 (in floating-point format). Photoshop can load 16-bpc images but 99% of its tools are disabled until you convert the image down to 8-bpc. In other words: the 16-bpc mode is there just for marketing.
There are some interesting HDR (high dynamic range) projects, such as HDRShop, and these formats are also used in several high-end 3D renderers, but I don't think they will become mainstream until Photoshop adopts them.
Unfortunately, Adobe insists on minor updates instead of doing what Photoshop (and Premiere, and several other of their products) needs, which is a complete rewrite.
High-end 3D renderers also have very good "film grain" simulation (film grain is not just random noise, it has very specific characteristics), and other tricks that can make CGI "feel" almost exactly like traditional analog media. But again, this is not something you'll find in Photoshop.
RMN
~~~
havent been able to get to the site because of you lot bringing it down but... is this related to the technology used in NASA's docking cameras? I remember reading that they developed a camera that worked exactly as the /. story described, in order to combat the problem of losing focus on the target spacecraft during docking manoeuvers. The report I read was in New Scientist, probably 3 years ago?
I'd go and find it but NS archives are subscription only. I really ought to get round to subscribing, I buy it often enough...
-Baz
... and I can't find out because the site is /.'ed :-( :-) but some of us nature photographers do.
is this: Can this technology be used to control (not just increase, but also decrease) depth of field at image processing time? More specifically, can I get selective focus *after* creating the image? In criticizing my own work, I ususally wish I had openned up for *less* depth of field. I realize that sports photographers don't have this problem
Although Colorado University may never forgive me, this address has links to the research papers as well as more images: http://www.colorado.edu/isl/
That's because Photoshop & most digital cameras only use RGB colorspace (24 bits) which is a crappy color space, and one that we're currently stuck with because of our display devices.
High Dynamic Range Images use a higher bit depth (12 bits per chanel?). Many of the Nikon cameras can save out these 12 bit/channel images, which, with the proper manipulation software (HDRShop, others) can be used for much finer and subtler manipulation.
So, (math skills permiting), I make that out as 4096 levels per channel, as opposed to the current 256/channel in a standard 24 bit image.
It's still an RGB system, but it's a much better RGB system.
The next step is to get manufacturers on board & start making HDRI Video Cards & Monitors.
What were you expecting?
Some more info from
Boulderdailycamera
Boulder startup gets deal with major optics player
By Anthony Lane
For the Camera
A Boulder-based startup, which makes technology that greatly improves the clarity of images through a lens, is poised to grow after signing a deal with one of the world's premier lens and microelectronics makers.
CDM Optics is a private company with sales last year of about $1 million, according to R.C. "Merc" Mercure, CDM's chairman and chief executive.
Next year, sales are expected to double with CDM's new partnership with the optical engineering company Carl Zeiss, a renowned manufacturer of microscopes, lenses and other instruments.
"The world's oldest optical company has joined forces with the most modern," said Ed Dowski, vice-president of CDM Optics.
The moving parts and multiple lenses of microscopes and certain cameras are precisely engineered to control aberrations and to produce a sharp image where someone wants it -- on a piece of paper, a slide or a computer screen.
Over centuries, scientists have devised ways to make sharp images of ever-smaller and more distant objects, but could do little to overcome the unchanging rules governing light and the formation of a focused image.
"There were no revolutionary changes in optics for 200 years," said Dowski.
CDM Optics produces an unusual type of "lens." Added to a standard lens, it produces images that actually appear blurry.
In fact, "There doesn't seem to be any part of the image that is more focused than any other," said Mercure, who was the co-founder of Ball Brothers Research Corp., which became Ball Aerospace.
A uniformly unfocused image may seem an unlikely goal, but after being digitally processed, the result is an image that is entirely in focus.
Mercure holds a poster with four pictures of a pack of crayons. Two were produced with a standard digital camera and the other two with a digital camera equipped with CDM's Wavefront Coding technology.
In one of the images from the standard camera, only a few crayons in the middle of the pack are in focus. To bring more of the crayons into focus, the photographer would have to decrease the size of the hole through which light enters the camera.
In the resulting image, more crayons are in focus, but it appears grainy as a result of less light hitting the camera's digital detector.
The difference between the two pictures produced with CDM's technology is more dramatic. The first is hazy -- it is an unprocessed image that would not ordinarily be seen.
In the second picture, all of the crayons from front to back are in focus without the graininess from the standard camera.
Dowski said applications for the technology that allows lenses to produce such images are numerous.
"You can either make lenses cheaper, sharper or both," he said.
Sharper images may be beneficial for many types of optics. A microscope, for instance, may magnify an object to 100 times its actual size with only a sliver 1 micron thick in focus.
"We can give a microscope up to 15 microns of focus," Mercure said.
One area in which this improved depth of field might be useful is in vitro fertilization. Ordinarily, a doctor produces a great number of embryos and monitors them for several days before implanting several. The goal is cause a successful pregnancy while minimizing the number of multiple births.
The problem is that after about three days, embryos are difficult to monitor with an ordinary microscope. The embryologist must guess which embryos are most likely produce a successful pregnancy.
Using Wavefront Coding technology, Mercure said, embryologists should be able to monitor the embryos for four or five days, thus reducing the number of embryos that must be implanted to have the same chance of a successful pregnancy.
The same increase in depth of field
"He is no fool who gives what he cannot keep in order to gain what he cannot lose."
Some of them are these days (wow! talk about low yield wafers!)
I doubt its that bad, since a camera can deal with a sparkling of 'dead' sensors, while pretty much any defect will kill a CPU.
autopr0n is like, down and stuff.
In case you were /.'d, most of the images from the CDM Optics website are also available here:
more images of increased depth
Actually, that's not true. Film captures color as realistically as the photochemicals can react to the incoming photons.
You can tell a great deal about the character of a man by observing those who hate him.
Maybe just the same info because I have not been able to get through to the original links.e ss/tech/27 bcdm.html
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Here is a news paper article.
http://www.boulderdailycamera.com/busin
and another.
http://www.alteich.com/tidbits/t012802.
and some images.
http://www.colorado.edu/isl/intimages/3c
Slide film captures the colour exactly as it was, whereas digital rounds it to the nearest bit.
This is what we refer to as "argument by bizarre definition".
Slide film captures color via photochemicals that change in response to light. Digital cameras capture color via sensors that signal in response to light. Saying that one is better "by definition" is patently absurd.
If slide film is inherently perfect, why are there so many different slide films with different color responses? If slide film captures color "exactly as it was", why is Fuji Velvia widely known for producing great landscape shots but murdering skin-tones? Slide film has all the same color concerns that any other capture method has -- good red response but poor greens, or great blues but muddy purples, for instance. Nothing is perfect, especially when the only real way to judge them is using the also-imperfect human eye.
I'm not basing my "better color" assertion on a bizarre definition of the abstract ideal. It's just my opinion, but I hold that my professional digital SLR, with little or no post-processing, produces better color than anything the film world has to offer. "Good color" is a subjective thing, and while you may disagree with me about that (cite examples please!), I stand by my statement.
ZFS: because love is never having to say fsck
Projecting my digital photos using a video projector gives them a vividness unlike anything I've ever seen in a hard copy. There's an "inner glow" to a projected image that paper just can't match. ;-)
Nothing for 6-digit uids?
It may be more vivid, due to some post-processing tricks, but it will never be as real or as authentic. Slide film captures the colour exactly as it was, whereas digital rounds it to the nearest bit. Slide film colour is as faithful and rich as the real thing.
This sounds just like the whole 'Analog sound is warmer' argument I hear from some guy that just spent $15k on a stereo.
"We returned the General to El Salvador, or maybe Guatemala, it's difficult to tell from 10,000 feet"
If anything, as other people posted, digital is closer to the "real thing".
One person mentioned that Fuji Velvia is great for landscapes but murders skin tones. This is because the sensitivity curve of a digital can be easily optimized, while it's very difficult to tweak the sensitivity and linearity of films based on chemical reactions.
As to rounding to the nearest bit - There's a lower limit in both electronic and film recording of the precision that a light level can be recorded which is distinguishable from noise. This is called the "noise floor" - Use enough bits, and then all the bit roundoffs will be well below the noise floor of even film media. (Which does indeed have a noise floor, just as digitals do. The nice thing about digitals is that with improved electronics and sensors, the noise floor of the sensor is dropping while film is staying the same. One of the things "pro" digitals are known for is having far less noise than lower-end digitals, and those improvements are constantly moving down to the consumer level.)
And for those that WANT the nonlinearities/quirks of film - All a camera manufacturer has to do is model the nonlinearities of major film types and then they can easily be emulated, just like guitar amps that use modeling techniques to emulate older units.
retrorocket.o not found, launch anyway?
http://www.economist.com/science/tq/displayStory.c fm?story_id=1476751
"It take 9 months to bear a child, no matter how many women you assign to the job."
Since the corporate site is still down, the best place to read about this is probably the website of the Imaging Systems Laboratory at the University of Colorado at Boulder, which I think is where all this technology was originally developed. Someone else posted that link elsewhere in the comments, but I will post it again here, properly hyperlinked for convenient Slashdotting.
"It take 9 months to bear a child, no matter how many women you assign to the job."
Most photographers want LESS depth-of-field than the current crop of digital cameras provide.
Only amateurs want "everything from here to infinity" to be in-focus.
The advantages of selective depth-of-field cannot be understated. The ability to have the background be completely soft and have the subject be the only thing in sharp focus (thereby drawing the viewer's attention to it) is a huge advantage of film over digital.
For example, on Attack of the Clones, the guys at ILM actually had to process the images to give them less depth-of-field, because the cameras couldn't get as little depth-of-field as the cinematographer wanted.