Kyle Rittenhouse murder trial digital image inlarging question.

Started 6 months ago | Discussions thread
bjn70 Veteran Member • Posts: 4,537
Re: Kyle Rittenhouse murder trial digital image inlarging question.

An upscaled image can create false detail, detail that wasn't there.  Digital images are not intended to be viewed that way, zoomed in that much.  Consider a photo taken with a sensor that has AA filter compared to a sensor that does not.  I did a comparison between a D7200 and D750 of the same subject.  Viewed at 100% the D7200 appeared to have more detail but I think it was false detail.  I could sharpen the D750 image to make it look closer to the D7200 image.  This is not adding pixels, just altering pixels, but it's trying to create data that wasn't there.  Sharpening can add various artifacts that could worst case be interpreted as something that isn't there.  How do we know that one side is not testing the image with different upscaling and sharpening algorythms to achieve the result that they want?

If I'm trying to check sharpness of a lens I will sometimes zoom in 100% and I've noticed that zoomed in that far might not give a good representation of sharpening, I might have to zoom back out by one step in order to see the image better.  If the expert witnesses would do this then there would be no question about upscaling.

I suppose the answer in a trial setting is to give the evidence to both sides, in this case the digital image, and let both sides determine what they thing is represented by the image, and then they would have to bring in expert witnesses to try to explain that what was done to the image was acceptable or not acceptable.  The expert would first have to explain that what you see on television of a blob in the photo turning into a recognizable face through computer magic is not reality.

I seem to remember that the standard Windows photo viewer would pixelate if you zoomed in too far, but the version I have now does some form of upscaling.

Small joke here, for anyone who remembers compression software such as ZIP.  One guy tells his friend that he ran his data through the zip program time after time until he got it down to just one byte.  His friend said "wow, what was that byte".  He said "I'm not telling you that!  You'd have all of my data."  This is sort of like compressing a photo down to one pixel and then someone thinking they could recreate the whole image by repeated upscaling.

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