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Lens-Free Flat Cameras Make Use of Pinhole Technology (npr.org)

Posted by yaelk on from the what-do-you-see-through-your-lens dept.

RhubarbPye writes: As reported on NPR, "Engineers in Texas are building a camera that can make a sharp image with no lens at all." By incorporating millions of individual pinholes with photoreceptors and postprocessing software, this camera system has been reduced to minimal thickness. Cameras in the wallpaper? A new phase of wearable cameras? What other applications for this technology could be developed?

8 of 65 comments (clear)

  1. Re:I must be missing something... by Frosty+Piss · · Score: 3, Informative

    So, let's see if I get this right. They rediscovered something, that everyone from the 1990's and 80 years prior learned to make as part of science class...and simply applied modern technology to it.

    No, you didn't get it right. But that's not surprising, clearly you didn't read the article.

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  2. Dynamic range? by RightwingNutjob · · Score: 4, Insightful

    TL;DR. Most uncooled camera chips give you maybe 10 or 11 bits of dynamic range, and light is subject to Poisson noise, meaning the brighter a pixel, the noiser it is in absolute (not relative) terms. If you have to solve a big giant matrix inversion to do the job of a collimating lens, you're composing each pixel as a sum of many others instead of just itself, some of them being way brighter than the reconstructed image, meaning your reconstructed pixel is always noisier. Cool idea, and certainly has its applications, but the best images will always come from big fat optics.

    1. Re:Dynamic range? by Arkh89 · · Score: 4, Insightful

      No. First, on these you are mostly limited by the thermal noise of the sensor which is miles above the photon noise for this application. Then you are still thinking that a pixel receives the same flux (power per surface area) as a traditional camera. This is not correct as each of the pixels collect flux from a much larger angular portion of the scene (due to the lack of optical focusing).

    2. Re:Dynamic range? by Ungrounded+Lightning · · Score: 4, Informative

      If you have to solve a big giant matrix inversion to do the job of a collimating lens, you're composing each pixel as a sum of many others instead of just itself, some of them being way brighter than the reconstructed image, meaning your reconstructed pixel is always noisier.

      Not really.

      When you average a large number of samples the noise tends to partially cancel out while the signal keeps adding up. Though the noise goes up with more samples, the signal goes up more, improving the signal to noise ratio. Even if you end up adding in some bright signals, with extra noise, that's still stomped by signal when you have enough samples.

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    3. Re:Dynamic range? by Anonymous Coward · · Score: 3, Informative

      No, the original poster was more correct. They're not averaging together a bunch of pixels, but applying an inverse matrix , which will weigh pixels differently, and quite frequently can involve very high weights assigned to noisier signals. This can result in an emphasis that amplifies noise. There is a lot of work done on different ways of clipping or modifying such matrix equations to make it slightly less accurate in an ideal world, but much less noisy in the real world.

      Also, no averaging of noise will happen if you try to produce images with similar pixel count to the number of detectors. And if you do use more sensors than resulting pixels, the averaging increases signal to noise ratio only in general when the noise is independent, but in this case there will be some strong correlations that can lower that signal to noise ratio in some cases.

  3. Re:I must be missing something... by gl4ss · · Score: 3, Interesting

    I suspect that if you put a lens on it, you would end up with a light field camera.

    aaaaanyways... this is wikipedia on light field camera: "A light field camera, also known as plenoptic camera, captures information about the intensity of light in a scene, and also captures information about the direction that the light rays are traveling in space. One type of light field camera uses an array of micro-lenses placed in front of an otherwise conventional image sensor to sense intensity, color, and directional information. Multi-camera arrays are another type of light field camera. Holograms are a type of film-based light field image."

    which sounds almost exactly like a variation of this. it's the same exact concept.

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  4. Re:I must be missing something... by shanen · · Score: 3, Insightful

    Actually it's more like the compound eye of insects, but 'wired' differently.

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  5. Nothing is new under the sun? by Lluc · · Score: 4, Interesting
    The way the NPR article describes this, it is no different from Uniformly Redundant Arrays, i.e. Coded Aperture Imaging: see https://en.wikipedia.org/wiki/... If you look at the 1998 paper, "Uniformly Redundant Arrays" by Busboom et al, the first sentence describes work from the 1960s:

    Coded aperture imaging (CAI) (Mertz and Young, 1961; Dicke, 1968) has matured as a standard imaging technique in X–ray and Gamma-ray astronomy. It is capable of combining high angular resolution with good photon collection efficiency by using a mask consisting of transparent and opaque elements placed in front of a position sensitive detector (Figure 1).

    So is the only innovation here using more pinholes, more pixels, and more processing than were around in the 1990s?