TV shopping

[firstfrost]

So, after many decades of faithful service (albeit somewhat tilted-screen, purple-blotched service), tirinian's TV finally gave up the ghost. So harrock (having the most interest in a Spiffier TV) and I trundled off to shop for one. The walls full of TVs are interesting in ways that I hadn't realized before.

Yes, this one is brighter, that one is more red, and so on. But there were also the TVs that were implementing some sort of unsharp mask, and the ones that weren't. harrock liked the sharpened pictures better, because they were (obviously) clearer. I liked the un-sharpened ones better because the sharpened ones were Cheating.

An odd irrationality there. I don't consider it cheating for the TV to actually be displaying static images changing very very fast, in an attempt to convince me that it's motion. I don't consider it cheating for them to use those little red, green, and blue dots instead of dots of every color. So why is sharpening cheating? (On the other hand, maybe they were all doing the same thing and the ones I thought were cheating had overshot. Then at least I'd be consistent. :) )

Comments

[chenoameg.livejournal.com]

Ok, that technology is really cool.

Cheating or not, aren't neat tech toys work it?

[navrins]

Thanks for the link - I've always wondered what an unsharp mask is, and that gives a very understandable explanation.

[kirisutogomen.livejournal.com]

Never mind how much the TV is cheating -- your eyes and brain are cheating way more than that. Not only are they already employing unsharp masks, but they're doing crazy things like entirely making stuff up to fill in your blind spot.

[firstfrost.livejournal.com]

Yeah, I amuse myself on weekend mornings by making spots on the ceiling vanish in my blind spot. :)

[algorithmancy.livejournal.com]

In my mind, the question is: if the unsharp mask is such a great trick, why wouldn't the broadcaster (or the filmmaker) apply it to the original image before they sent it to you? And what happens when your TV unsharp masks something that has already been unsharp masked? I wouldn't be surprised if you enter the realm of "disturbingly oversharp," though I'm not precisely sure what that looks like.

It seems like the unsharp mask is particularly useful when using your high-res HDTV to view lower-res signals, where the mask can use your higher resolution to infer detail. This probably still happens a lot of the time if you have an HDTV and are watching non-HD cable or DVDs. In that case it might not matter if the original signal had been "pre-sharpened." But as the signals "catch up" to the TVs, the unsharp mask fitler might become less desirable, or undesireable. This is all just armchair conjecture. Actual experts should feel free to correct me.

Maybe that's the reason why it's "cheating;" the TV is deciding that the image coming from the broadcaster isn't good enough for you, and needs to be "spruced up" for your benefit.

[firstfrost.livejournal.com]

I think that it's that a good unsharp mask (as opposed to one that does nothing, or one that produces annoying haloes) is dependent on the resolution. Film is high enough resolution to not bother, while when broadcasting, you have one signal fits many TV sizes and resolutions. So I *think* you'd want to do it on the screen end, rather than on the signal end. But yeah, I wonder whether there's options to tweak it if it turns out to be set too high, or interpreting something that doesn't need it.