4 ms·

As Twisol said, zooming doesn't inherently require interpolation. But when it does require interpolation, it's usually an extremely simple and well-understood f

by _djo_ 5y ago

As Twisol said, zooming doesn't inherently require interpolation. But when it does require interpolation, it's usually an extremely simple and well-understood form like nearest neighbour interpolation that's not going to result in things like faces being inserted. It also only uses the available data in the image itself on which to work. It's fundamentally different from neural network-driven inference and interpolation that attempts to fill in pixels using evidence from other images that the network has been trained on.

iainmerrick 5y ago
How is a non-expert, and somebody whose job specifically requires them to be sceptical and to question unstated assumptions, supposed to be sure of that?
- _djo_ 5y ago
  It's a simple enough thing to verify, or require the defence (in this case) to substantiate the claim without throwing out the method of showing evidence entirely. Courts have to deal with questions like this all the time and handle them well enough. Technology isn't magic, nor do we have to go down a rabbit hole on each point about what might be there rather than what is there.
  - A4ET8a8uTh0 5y ago
    It is not magic, but, as other posters alluded, sometimes it can be merely an educated guess. It is hard to accept a life changing verdict based on a guess.. even if it is an educated one. So no, each time a given technique is used, the way it works has to be explained so that a decision based on facts of the case is made.
    - _djo_ 5y ago
      Nothing wrong with that, but a common sense explanation by an expert witness ought to be enough. Does Apple need to be dragged into each and every case to testify as to how pinch to zoom works, as was demanded here? Courts have established mechanisms for handling technical questions around evidence. It's not like any of this is new.
      - jtbayly 5y ago
        All that was required was an expert witness, right? So what’s the problem?
        _djo_ 5y ago
        The judge did not give the prosecution time to find an expert witness, did not ask his clerks to search for similar usage of iPad zooming in previous cases, and did not require the defence to provide expert testimony of their own to substantiate their claim. In the end the iPad was not used. Instead a 4K TV was used, which ironically probably upscaled the image too.
        vorpalhex 5y ago
        The judge does not provide clerks for research. The party introducing the evidence does that.
        _djo_ 5y ago
        This wasn’t a new evidence exhibit being introduced. Did you actually read the transcript, or are you reacting to this story based on what you’ve read elsewhere?
        ClumsyPilot 5y ago
        "In the end the iPad was not used. Instead a 4K TV was used" Okay, so what's the issue then?
  - syshum 5y ago
    >>and handle them well enough. I would argue they DO NOT handle them well enough at all, and I have a feeling that if the person on trial had a different political affiliation you would also be claiming they do not. Courts routinely get technology wrong, and use this the send innocent people to prison all the time. I would say the courts get technology related evidence wrong more than they do correct.
    - _djo_ 5y ago
      > I have a feeling that if the person on trial had a different political affiliation you would also be claiming they do not. That's an ad hominem argument. In truth I don't care who's on trial, as the outcome of this specific trial is at this point an American culture war & politics issue that I'm uninterested in. I am interested in how well courts handle technology and whether either prosecutors or defence attorneys can throw a wrench in proceedings with fanciful woo like "iPads, which are made by Apple, have artificial intelligence in them that allow things to be viewed through three dimensions and logarithms", and have that tolerated by judges who themselves are often technologically illiterate.
      - syshum 5y ago
        That is not a direct quote, further it is telling you are not pointing out all the ways the prosecutors are using technologically illiteracy to manipulate both the judge and the jury into a false narrative about what actually happened. Sure the defense in this case is fucking terrible, no arguments there, they are 100% technologically illiterate. That however does not excuse the complete and utter perversion of the truth the prosecution is attempting to claim as "evidence"
  - trothamel 5y ago
    This inverts the burden. The prosecution proposed the exhibit, and so the burden is on them to show that everything about it - that the chain of custody was valid, that the processing done on it was meaningful - is correct. It's not the defense's place to prove them wrong. All of the other evidence was processed through forensics software, and displayed on Windows laptops. Then, at the last minute, the prosecutor asks to show this late-discovered evidence on an iPad. Watching the trial, that felt suspicious - why should this one piece of evidence be shown in a novel way?
    - _djo_ 5y ago
      It’s not a new exhibit being introduced, and the zoomed in form is not evidence. Therefore there’s no chain of custody question. It was being used to show the footage to the witness on the stand, in order for them to explain what’s shown on it. As has been done in American courts hundreds of times before. Now sure, the witness and prosecution or defence could argue that a witness doesn’t need to make guesses about what they’re seeing on zoomed in low-quality footage when under cross-examination. That happens all the time, too. What doesn’t happen every time is for iPads to be rejected for this purpose because of magical AI ‘logarithms’ inventing imagery.
      - trothamel 5y ago
        I believe this was entered into evidence separately from the video as a whole: https://twitter.com/frostycharacter/status/1459722429949878276/photo/1 https://twitter.com/frostycharacter/status/14597224299498782... That means the jury will be able to see this as its own exhibit. (It may have been assigned two exhibit numbers.) And I'd say it makes sense. Each additional processing step can change the image. For example, if one used the waifu2x algorithm to scale the image up, that would certainly be wrong.
vidarh 5y ago
It's only fundamentally different until some image manipulation program chooses to label AI driven interpolation as zoom. Language is malleable, and so while it may be paranoid to question a feature labelled as zoom now, it's an open question how long that will last.
- _djo_ 5y ago
  It was a claim made by the defence, which the judge insisted that the prosecution prove the absence of, rather than requiring the defence to substantiate. That's not how technical claims of that nature are normally handled.
  - ImprobableTruth 5y ago
    The prosecution presented modified evidence, claiming that the modification doesn't change it, which the defense objected to. Why would the burden of proof not fall on the prosecution?
    - _djo_ 5y ago
      Zooming into a video using the built-in feature on a device is modified evidence now? We'd have to rerun a bunch of trials in that case. The fantastical claim was from the defence. Onus should be on them to prove it, rather than making the prosecution prove a negative.
      - core-utility 5y ago
        What does "built-in" have to do with anything? The entire point of the issue was that it wasn't just zoom in, it was enlargement (think upscaling). The software has to actively interpolate and add pixels where it thinks they're necessary in order to do so, and that changes the image. In most cases, it's probably not a big deal. But when it's from a nighttime camera of a person several hundred feet away that's only a few pixels in the original frame, there's a lot to go wrong there.
ImprobableTruth 5y ago
This is just pivoting. In this case zooming uses interpolation which "has the potential to introduce false information" exactly as you mentioned. It using only the available data doesn't mean that interpolation can't go wrong. So what if it's not AI? And yes, it's so well understood that the prosecution had no idea of what's going on, claiming that it's "common sense" that it works just like a magnifying glass, which is simply wrong. Using bilinear (or bicubic) interpolation makes the edges of an image blurrier, especially when you're zooming in as much as they did on low-quality footage.
- _djo_ 5y ago
  Come now, you're reaching. The defence attorney specifically claimed that "iPads, which are made by Apple, have artificial intelligence in them that allow things to be viewed through three dimensions and logarithms." and "[The iPad] uses artificial intelligence or their logarithms to create what they believe is happening. So this isn't actually enhanced video; this is Apple's iPad programming creating what it thinks is there, not what necessarily is there." Aside from the confusion about logarithms, where I presume he meant algorithms, and the false claim about 3D, the defence was making a claim about artificial intelligence being used to upscale the footage. Which is inaccurate, and a specific claim being made that's unsupported by any evidence. Funny enough, the same sort of question arose with regard to a crime scene image that was enlarged by the state's forensic lab, but a simple explanation of the mechanism used was deemed sufficient.
  - ImprobableTruth 5y ago
    I'm reaching? Like, why would the defense's wrong argument be relevant? You're not arguing with the defense here. Your claim was that the judge's call is wrong because zooming doesn't actually do interpolation and has thus no potential to introduce wrong information. I've told you that zooming in this case does interpolate and that interpolation has the potential to go wrong.
    - jschwartzi 5y ago
      When interpolation goes wrong it’s predictably wrong, which is not true of more complex algorithms using AI. If we can predict how it goes wrong we can extract the meaningful information from it.

by _djo_ 5y ago

iainmerrick 5y ago

How is a non-expert, and somebody whose job specifically requires them to be sceptical and to question unstated assumptions, supposed to be sure of that?

_djo_ 5y ago
It's a simple enough thing to verify, or require the defence (in this case) to substantiate the claim without throwing out the method of showing evidence entirely. Courts have to deal with questions like this all the time and handle them well enough. Technology isn't magic, nor do we have to go down a rabbit hole on each point about what might be there rather than what is there.
- A4ET8a8uTh0 5y ago
  It is not magic, but, as other posters alluded, sometimes it can be merely an educated guess. It is hard to accept a life changing verdict based on a guess.. even if it is an educated one. So no, each time a given technique is used, the way it works has to be explained so that a decision based on facts of the case is made.
  - _djo_ 5y ago
    Nothing wrong with that, but a common sense explanation by an expert witness ought to be enough. Does Apple need to be dragged into each and every case to testify as to how pinch to zoom works, as was demanded here? Courts have established mechanisms for handling technical questions around evidence. It's not like any of this is new.
    - jtbayly 5y ago
      All that was required was an expert witness, right? So what’s the problem?
      - _djo_ 5y ago
        The judge did not give the prosecution time to find an expert witness, did not ask his clerks to search for similar usage of iPad zooming in previous cases, and did not require the defence to provide expert testimony of their own to substantiate their claim. In the end the iPad was not used. Instead a 4K TV was used, which ironically probably upscaled the image too.
        vorpalhex 5y ago
        The judge does not provide clerks for research. The party introducing the evidence does that.
        _djo_ 5y ago
        This wasn’t a new evidence exhibit being introduced. Did you actually read the transcript, or are you reacting to this story based on what you’ve read elsewhere?
        ClumsyPilot 5y ago
        "In the end the iPad was not used. Instead a 4K TV was used" Okay, so what's the issue then?
- syshum 5y ago
  >>and handle them well enough. I would argue they DO NOT handle them well enough at all, and I have a feeling that if the person on trial had a different political affiliation you would also be claiming they do not. Courts routinely get technology wrong, and use this the send innocent people to prison all the time. I would say the courts get technology related evidence wrong more than they do correct.
  - _djo_ 5y ago
    > I have a feeling that if the person on trial had a different political affiliation you would also be claiming they do not. That's an ad hominem argument. In truth I don't care who's on trial, as the outcome of this specific trial is at this point an American culture war & politics issue that I'm uninterested in. I am interested in how well courts handle technology and whether either prosecutors or defence attorneys can throw a wrench in proceedings with fanciful woo like "iPads, which are made by Apple, have artificial intelligence in them that allow things to be viewed through three dimensions and logarithms", and have that tolerated by judges who themselves are often technologically illiterate.
    - syshum 5y ago
      That is not a direct quote, further it is telling you are not pointing out all the ways the prosecutors are using technologically illiteracy to manipulate both the judge and the jury into a false narrative about what actually happened. Sure the defense in this case is fucking terrible, no arguments there, they are 100% technologically illiterate. That however does not excuse the complete and utter perversion of the truth the prosecution is attempting to claim as "evidence"
- trothamel 5y ago
  This inverts the burden. The prosecution proposed the exhibit, and so the burden is on them to show that everything about it - that the chain of custody was valid, that the processing done on it was meaningful - is correct. It's not the defense's place to prove them wrong. All of the other evidence was processed through forensics software, and displayed on Windows laptops. Then, at the last minute, the prosecutor asks to show this late-discovered evidence on an iPad. Watching the trial, that felt suspicious - why should this one piece of evidence be shown in a novel way?
  - _djo_ 5y ago
    It’s not a new exhibit being introduced, and the zoomed in form is not evidence. Therefore there’s no chain of custody question. It was being used to show the footage to the witness on the stand, in order for them to explain what’s shown on it. As has been done in American courts hundreds of times before. Now sure, the witness and prosecution or defence could argue that a witness doesn’t need to make guesses about what they’re seeing on zoomed in low-quality footage when under cross-examination. That happens all the time, too. What doesn’t happen every time is for iPads to be rejected for this purpose because of magical AI ‘logarithms’ inventing imagery.
    - trothamel 5y ago
      I believe this was entered into evidence separately from the video as a whole: https://twitter.com/frostycharacter/status/1459722429949878276/photo/1 https://twitter.com/frostycharacter/status/14597224299498782... That means the jury will be able to see this as its own exhibit. (It may have been assigned two exhibit numbers.) And I'd say it makes sense. Each additional processing step can change the image. For example, if one used the waifu2x algorithm to scale the image up, that would certainly be wrong.

vidarh 5y ago

It's only fundamentally different until some image manipulation program chooses to label AI driven interpolation as zoom. Language is malleable, and so while it may be paranoid to question a feature labelled as zoom now, it's an open question how long that will last.

_djo_ 5y ago
It was a claim made by the defence, which the judge insisted that the prosecution prove the absence of, rather than requiring the defence to substantiate. That's not how technical claims of that nature are normally handled.
- ImprobableTruth 5y ago
  The prosecution presented modified evidence, claiming that the modification doesn't change it, which the defense objected to. Why would the burden of proof not fall on the prosecution?
  - _djo_ 5y ago
    Zooming into a video using the built-in feature on a device is modified evidence now? We'd have to rerun a bunch of trials in that case. The fantastical claim was from the defence. Onus should be on them to prove it, rather than making the prosecution prove a negative.
    - core-utility 5y ago
      What does "built-in" have to do with anything? The entire point of the issue was that it wasn't just zoom in, it was enlargement (think upscaling). The software has to actively interpolate and add pixels where it thinks they're necessary in order to do so, and that changes the image. In most cases, it's probably not a big deal. But when it's from a nighttime camera of a person several hundred feet away that's only a few pixels in the original frame, there's a lot to go wrong there.

ImprobableTruth 5y ago

This is just pivoting. In this case zooming uses interpolation which "has the potential to introduce false information" exactly as you mentioned. It using only the available data doesn't mean that interpolation can't go wrong. So what if it's not AI? And yes, it's so well understood that the prosecution had no idea of what's going on, claiming that it's "common sense" that it works just like a magnifying glass, which is simply wrong. Using bilinear (or bicubic) interpolation makes the edges of an image blurrier, especially when you're zooming in as much as they did on low-quality footage.

_djo_ 5y ago
Come now, you're reaching. The defence attorney specifically claimed that "iPads, which are made by Apple, have artificial intelligence in them that allow things to be viewed through three dimensions and logarithms." and "[The iPad] uses artificial intelligence or their logarithms to create what they believe is happening. So this isn't actually enhanced video; this is Apple's iPad programming creating what it thinks is there, not what necessarily is there." Aside from the confusion about logarithms, where I presume he meant algorithms, and the false claim about 3D, the defence was making a claim about artificial intelligence being used to upscale the footage. Which is inaccurate, and a specific claim being made that's unsupported by any evidence. Funny enough, the same sort of question arose with regard to a crime scene image that was enlarged by the state's forensic lab, but a simple explanation of the mechanism used was deemed sufficient.
- ImprobableTruth 5y ago
  I'm reaching? Like, why would the defense's wrong argument be relevant? You're not arguing with the defense here. Your claim was that the judge's call is wrong because zooming doesn't actually do interpolation and has thus no potential to introduce wrong information. I've told you that zooming in this case does interpolate and that interpolation has the potential to go wrong.
  - jschwartzi 5y ago
    When interpolation goes wrong it’s predictably wrong, which is not true of more complex algorithms using AI. If we can predict how it goes wrong we can extract the meaningful information from it.