Could you actually see photos made from RAW files?

Discussion in 'Digital Photography' started by aniramca, May 30, 2009.

  1. aniramca

    Chris H Guest

    EEPROM, Flash etc often loaded into RAM at runtime. However often it is
    in ASICS and FPGA's with softcores.

    BTW ROMS are rarely used these days. You are 15 years out of date
    Yes... But this contains firmware. That is what is in these ASICS
    Not true. You seem to be over a decade out of date.
    He is correct. You are not.

    If you would like a 101 on embedded systems I am free tomorrow afternoon
    when I finish presenting to the UK Ministry of Defence on this topic in
    the morning.

    See
    http://www.safety-club.org.uk/diary.html?opt=detail&id=80

    and scroll down to the speakers I am the first one after the welcome.

    Floyd, what is your expertise in this field?

    Not at all. I can provide the tools for the software (firmware) in the
    ASIC that takes the information from the sensor.
    No. We only work in the embedded sector. Mainly high reliability
    systems.
     
    Chris H, Jun 3, 2009
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  2. aniramca

    Eric Stevens Guest

    For this topic you have to understand the nature of the underlying
    quantum mechanics. Quantum mechanics is probabalistic.
    Imagine you are counting bricks and you only have an old fashioned
    spring scale. For the sake of simplicity, lets say each brick weighs 1
    lb. How do you count integer bricks with your analog scale?

    1 lb on the scale means one brick. 12 lbs on the scale means 12
    bricks. 12,2 lbs on the scale probably means 12 bricks. So too does
    12.45 lbs or 11.6 lbs. You can never be entirely certain but the more
    precise the scale more confident you can be. For this reason the
    accuracy of your brick count is "subject to statistical error
    limitations".

    The same thing applies when electronics counts electrons. Electrical
    measuring devices can have a level of accuracy beyond the
    comprehension of people used to the mechanical world. Eight
    significant figures is not unusual. I don't know what is employed in
    camera sensors but I expect the better ones will be capable of
    counting electrons to a high order of precision. Their data going in
    is integer. Just like the brick counter, the data coming out will be
    integer, even if it is obtained via what you call analog circuitry.
    What then is the significant difference in your mind?
    Lets ride with your digital to analog for the moment (although I don't
    entirely agree with it). Lets say 1 electron is converted by the
    process to a decimal value of 1.2 (it doesn't matter 1.2 what). 2
    electrons give 2.4. 3 electrons give 3.5. .... 6 electrons give 7.5
    and so on. You can construct a table relating number of electrons in,
    and the decimal value out.

    Now, say you have an image which is presented as a RAW data file. Say
    you also know all the details of the process by means of which RAW
    data has been derived from the output of everything after the table
    above. You use this to work back to determine that for a particular
    sensel the output of the A to D process was 3.6. Using the table you
    cconclude that that means that the sensel had probably captured 3
    electrons. You can do this for every sensel on the sensor and by this
    means you can reconstruct the original image which was projected onto
    the sensor.
    Find an example and quote from it.
    I did? Please find where.
    What's assinine about that?
    What I am saying is that changes must be of constant magnitude.
    Subject to the sensitivity of the sensor and its associated
    electronics, you cant have a very small change which simply isn't
    large enough to influence the data set. You either have a change or
    you don't.
    That's one of the factors I had in mind when I wrote "subject to
    statistical error limitations"
    That's another of the factors I had in mind when I wrote "subject to
    statistical error limitations".
    Think bricks. I'm glad to see you understand.
    But so what? We are considering what light each sensel was actually
    exposed to.
    "subject to statistical error limitations"



    Eric Stevens
     
    Eric Stevens, Jun 3, 2009
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  3. aniramca

    Eric Stevens Guest

    A damned good idea. I'm taking it right off line.



    Eric Stevens
     
    Eric Stevens, Jun 3, 2009
  4. aniramca

    Chris H Guest

    Yes to both
    Normally.
     
    Chris H, Jun 4, 2009
  5. aniramca

    Bob Larter Guest

    At this point, it's an analog voltage whose magnitude *approximately*
    corresponds to the number of photons that have hit the sensel, plus
    various kinds of noise. That voltage is then amplified (more noise)
    according to the ISO setting, & sent to an A-to-D converter, which
    generates a binary number that *approximates* the voltage out of the
    amplifier.

    Another factor is the fact that each sensel has a colour filter on top
    of it, so any single sensel that is hit by light of the wrong colour
    will not measure that light.
     
    Bob Larter, Jun 5, 2009
  6. aniramca

    Bob Larter Guest

    You'd still have a problem with read noise, etc. Minimising it is one of
    the reasons astronomers 'stack' images.
     
    Bob Larter, Jun 5, 2009
  7. aniramca

    Bob Larter Guest

    No, of course not, I'm just trying to provide a clear example. In real
    life, it's more a case of light levels falling at different distance
    between the steps available from the A-to-D converter, but that's a lot
    harder to visualise.
     
    Bob Larter, Jun 5, 2009
  8. aniramca

    Bob Larter Guest

    True, but it's extraordinarily rare for them not to be. In practice, any
    circuit with more than a few steps is considered to be analog.
    Sure, but the industry-standard name for such systems is 'analog'.
    Unusual, but still digital.
    No, I'm afraid not. Any digitisation of an analog signal is, by
    definition, approximate. The number you get out of your A-to-D converter
    should be a very close approximation to the input level, but there's a
    whole range of factors that introduce small errors.
     
    Bob Larter, Jun 5, 2009
  9. aniramca

    Bob Larter Guest

    Whoa! That's even better than I was thinking.

    Thanks Mr Duck! ;^)
     
    Bob Larter, Jun 5, 2009
  10. aniramca

    Chris H Guest

    NDA
     
    Chris H, Jun 5, 2009
  11. aniramca

    Eric Stevens Guest

    Is voltage analog when you are measuring it in integer steps?


    Eric Stevens
     
    Eric Stevens, Jun 5, 2009
  12. aniramca

    Chris H Guest

    Grow up. I am in a position to know and you are not.
    Then, as so often, you would be wrong.

    Just because you are an amateur programmer does not mean you understand
    embedded engineering. Stick to photography.
     
    Chris H, Jun 5, 2009
  13. aniramca

    Huge Guest

    Fallacious; Argument from authority. Put up or shut up.
     
    Huge, Jun 5, 2009
  14. aniramca

    Chris H Guest

    I put up.

    I also demonstrated why I am in a position to know.

    Floyd has demonstrated nothing so far bar unsupported opinion.
     
    Chris H, Jun 5, 2009
  15. aniramca

    Chris H Guest

    What you mean the "giggle snort"?

    Yes you did
    I am a credible source in the Embedded systems and electronics industry.

    However it is clear you are an aperture in the field of software and
    embedded systems.

    Well it does if al the sources I know are not public. All I know is we
    supplied the compilers for the core used in the ASICS

    Only about 5 years producing them professionally. You are using some of
    the equipment now.
    I have noticed in your many discussions you seem at odds with almost
    everyone.
     
    Chris H, Jun 5, 2009
  16. aniramca

    Bob Larter Guest

    Are you kidding?
     
    Bob Larter, Jun 5, 2009
  17. aniramca

    Bob Larter Guest

    You're confusing domains. Analog is analog, & digital is digital. You
    *will* get errors when you convert from one to the other.
     
    Bob Larter, Jun 5, 2009
  18. aniramca

    Chris H Guest

    He's not in the real world... BTW have a look at the C source code on
    his web site. Speaks volumes. :)
     
    Chris H, Jun 5, 2009
  19. aniramca

    tony cooper Guest

    Oh, this is painful. A fallacious Argumentum Ad Verecundiam is the
    fallacy of using an authority when that authority has no standing or
    expertise in the field of discussion. It would be a fallacious Ad
    Verecundiam if he used me as an authority because I have no standing
    in the field. The statement does not represent Chris as an authority.

    Chris is referring to unidentified "experts" (authorities) who have,
    presumably, standing and expertise. Unless Chris identifies the
    experts, and it can be ascertained that they do not have appropriate
    standing, there is no fallacious Argumentum Ad Verecuniam.
    You don't argue *by* non sequitur. A response could be a non sequitur
    if it "does not follow", but the above is not an example of that even
    if Chris is not in a position to know.
    That does not constitute a non sequitur.
    No, nothing in that statement attacks your character. While it
    questions the validity of your points by labeling them as no more than
    opinions, it does not malign your character. It is no more Ad Hominem
    than "You have not proven your point".

    Examples of an Argumentum Ad Hominem would include statements like
    "You are ignorant" as a response in argument. It does seem like we've
    heard that in here.

    Argumentum Ad Hominem is not "false logic". It is a fallacy of
    relevance.

    Later, we may cover your misuse of "out-of-kilter".
     
    tony cooper, Jun 5, 2009
  20. aniramca

    Chris H Guest

    I know. I was wondering why we are bothering. He seems out of synch with
    the rest of the world.
    Actually I *am* an authority in this field.
     
    Chris H, Jun 5, 2009
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