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The limits of "computational photography"

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Re: The limits of "computational photography"

#61

Post by ecpottinger »

nomel wrote: post #27
ecpottinger wrote: post #21

Earlier quoted context omitted.

That is what I was thinking. The poster said the photo looked okay at the moment they took a picture and the phone's processing takes over and he then gets junk. I wonder how hard to is to take 'RAW' photos without adding an app first.

You can use the camera app. It’s all in the settings menu for Pro models: https://support.apple.com/guide/iphone/take-apple-proraw-pho... This is a “there’s already a solution, but the average consumer wouldn’t know about it, because the defaults are made for them” type of problem. One could claim that it's a UI problem, and should be exposed in the Camera app. This may be true, but the files are 10 to 12 times large…

Sorry, I do not have an iPhone. How easy is the 'RAW' feature to find?

I understand what you mean about most users do not need such a feature. But while supporting computers I am surprise how many features of programs users do not know exist not just because they do not use them but also how hard it is to get at some features.

Personally, I seen too many programs where you need to know to turn OFF certain functions before you can enable some other feature. The users often never see what they needed because it is so hard to enable that feature without know they need to turn something else OFF.

Re: The limits of "computational photography"

#63

Post by throwanem »

delta_p_delta_x wrote: post #16

I would like to see computational photography applied to raw images from DSLRs and MILCs with APS-C and larger sensors. Perhaps Canon, Nikon, Sony, and Fujifilm could have built-in options in their cameras for ‘social media mode’, with a modicum of noise reduction (honestly unnecessary at ISOs lower than about 1600 for modern cameras), but drastically improved HDR and white balance. Many of these cameras are able to…

> I would like to see computational photography applied to raw images from DSLRs and MILCs with APS-C and larger sensors.

Wash your mouth out with soap! I did not spend five thousand dollars on a D850-based macro rig to have it produce results no better in quality than what I can get from my phone.

Re: The limits of "computational photography"

#64

Post by donkeyd »

kaba0 wrote: post #52
jlarocco wrote: post #20

I love my big, heavy Nikon DSLR, and there's really no comparing the images it takes with the ones from my iPhone. Especially in "tricky" lighting situations they're not even in the same ballpark. That said, there can be just as much (or more) "computational photography" going on with a digital camera as there is with a modern phone, the difference is that cameras and processing software give control to the user, and…

Do digital cameras really do anywhere near the same computations? Like, they usually have like some low-end shitty microprocessor at most, while for example an iphone has an insanely powerful CPU. Sure, plenty part of this processing happens in the ISP, but surely not everything.

No, they don't. It's not just the CPU, it's also that phones will often take bracketed exposures and use sensor data to align them correctly and automatically create an HDR image, for example. Either that or taking lots of short exposures and stacking them. It's not just in post processing, the magic already happens while taking the image itself.

People who think digital cameras do anything close to what modern phones do don't have a clue. They're the opposite of 'Phones can do anything a DSLR can' people and they are just as wrong.

Re: The limits of "computational photography"

#65

Post by account42 »

> For example, by stitching together multiple dark images to try to make a brighter one. (Dedicated cameras tend to have better-quality but conceptually similar options like long exposures with physical IS.) However, we are starting to introduce the core sin of modern computational photography: imposing a prior on the image contents. In particular, when we do something like stitch multiple images together, we are making an assumption: the contents of the image have moved only in a predictable way in between frames. If you’re taking a picture of a dark subject that is also moving multiple pixels per frame, the camera can’t just straightforwardly stitch the photos together - it has to either make some assumptions about what the subject is doing, or accept a blurry image.

This applies to dedicated cameras too though - physical image stabilization can compensate for camera motion but not for subject motion. The difference is that a) physical IS can compensate throughout each exposure, not just between exposure and b) the photographer is not bound to a black box algorithm but can instead use his own a priori knowledge to align the images if needed.

Re: The limits of "computational photography"

#66

Post by account42 »

delta_p_delta_x wrote: post #16

I would like to see computational photography applied to raw images from DSLRs and MILCs with APS-C and larger sensors. Perhaps Canon, Nikon, Sony, and Fujifilm could have built-in options in their cameras for ‘social media mode’, with a modicum of noise reduction (honestly unnecessary at ISOs lower than about 1600 for modern cameras), but drastically improved HDR and white balance. Many of these cameras are able to…

Pretty much all RAW processing includes computational photography - at the very least debayering, but likely more.

Re: The limits of "computational photography"

#67

Post by SSLy »

buildbot wrote: post #48
delta_p_delta_x wrote: post #16

I would like to see computational photography applied to raw images from DSLRs and MILCs with APS-C and larger sensors. Perhaps Canon, Nikon, Sony, and Fujifilm could have built-in options in their cameras for ‘social media mode’, with a modicum of noise reduction (honestly unnecessary at ISOs lower than about 1600 for modern cameras), but drastically improved HDR and white balance. Many of these cameras are able to…

There is no reason to do this. If you want to apply the algorithms and Iphone uses, simply take a burst and post process later for HDR or whatever. I remember being in middle school and messing around with Hugin and my Minolta bridge camera… People value quick shots/edits and don’t care about quality or editing things later don’t mind an iPhone doing all this behind the scene - but it is irreversible. The sort of err…

>camera manufacturers simply don’t have the same compute available.

what forbids them from buying the competitive SoCs from Qualcomm? Pride?

Re: The limits of "computational photography"

#69

Post by wnkrshm »

There are many more clever methods that one can use with CMOS that fall under computational photography or optics.

One very interesting one is ptychography (in microscopy often Fourier ptychography, since you can use Fourier optics to describe the optical system [0]), which uses a model of an optical system to get an image (iirc x7-x10 resolution) out of many blurry images, while knowing a bit about the optics in front of your image sensor - it can also work in remote sensing to some degree (better with coherent illumination though).

Edit: This is not just averaging or maxing pixels, it reconstructs the image using reconstructed phase information from having low-res pictures with different, known illumination or camera positions.

[0] https://www.youtube.com/watch?v=hece_x37ITg

Re: The limits of "computational photography"

#70

Post by wnkrshm »

jsmith99 wrote: post #55
killjoywashere wrote: post #39

> the relevant metric is what I call “photographic bandwidth” - the information-theoretic limit on the amount of optical data that can be absorbed by the camera under given photographic conditions (ambient light, exposure time, etc.). You mean, "resolution"?

'resolution' is usually used just to mean the number of pixels: nothing about how much ligh they capture or what sort of lens and processing.

Talking about optics, optical resolution is also a thing, i.e. whether you can resolve a certain target like a grid of micrometer-sized bars under a microscope.

Edit: That kind of resolution is induced by the optics and not by the sensor (if your optics can resolve the target, you can always add more optics to magnify the image if you have a low-pixel-resolution sensor).

Edit2: The poster you replied to is right that optical resolution is a constraint in terms of information that can be reconstructed after being imaged through a specific optical system.

An optical system filters light in phase space (imagine a space of position, angle and intensity of light in each point of the optical system, in a geometrical optics picture) and since some components are cut off, you cannot reconstruct an image to arbitrary fidelity, you lose information (or are stuck with a certain optical resolution).

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