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MarkusWandeltoday at 1:05 AM6 repliesview on HN

But does applying the same transfer function to each pixel (of a given colour anyway) count as "processing"?

What bothers me as an old-school photographer is this. When you really pushed it with film (e.g. overprocess 400ISO B&W film to 1600 ISO and even then maybe underexpose at the enlargement step) you got nasty grain. But that was uniform "noise" all over the picture. Nowadays, noise reduction is impressive, but at the cost of sometimes changing the picture. For example, the IP cameras I have, sometimes when I come home on the bike, part of the wheel is missing, having been deleted by the algorithm as it struggled with the "grainy" asphalt driveway underneath.

Smartphone and dedicated digital still cameras aren't as drastic, but when zoomed in, or in low light, faces have a "painted" kind of look. I'd prefer honest noise, or better yet an adjustable denoising algorithm from "none" (grainy but honest) to what is now the default.


Replies

101008today at 1:54 AM

I hear you. Two years ago I went to my dad's and I spent the afternoon "scanning" old pictures of my grandparents (his parents), dead almost two decades ago. I took pictures of the physical photos, situating the phone as horizontal as possible (parallel to the picture), so it was as similar as a scan (to avoid perspective, reflection, etc).

It was my fault that I didn't check the pictures while I was doing it. Imagine my dissapointment when I checked them back at home: the Android camera decided to apply some kind of AI filter to all the pictures. Now my grandparents don't look like them at all, they are just an AI version.

Aurornistoday at 1:52 AM

> For example, the IP cameras I have, sometimes when I come home on the bike, part of the wheel is missing, having been deleted by the algorithm as it struggled with the "grainy" asphalt driveway underneath.

Heavy denoising is necessary for cheap IP cameras because they use cheap sensors paired with high f-number optics. Since you have a photography background you'll understand the tradeoff that you'd have to make if you could only choose one lens and f-stop combination but you needed everything in every scene to be in focus.

You can get low-light IP cameras or manual focus cameras that do better.

The second factor is the video compression ratio. The more noise you let through, the higher bitrate needed to stream and archive the footage. Let too much noise through for a bitrate setting and the video codec will be ditching the noise for you, or you'll be swimming in macroblocks. There are IP cameras that let you turn up the bitrate and decrease the denoise setting like you want, but be prepared to watch your video storage times decrease dramatically as most of your bits go to storing that noise.

> Smartphone and dedicated digital still cameras aren't as drastic, but when zoomed in, or in low light, faces have a "painted" kind of look. I'd prefer honest noise, or better yet an adjustable denoising algorithm from "none" (grainy but honest) to what is now the default.

If you have an iPhone then getting a camera app like Halide and shooting in one of the RAW formats will let you do this and more. You can also choose Apple ProRAW on recent iPhone Pro models which is a little more processed, but still provides a large amount of raw image data to work with.

daharttoday at 1:59 AM

> does applying the same transfer function to each pixel (of a given colour anyway) count as “processing”?

This is interesting to think about, at least for us photo nerds. ;) I honestly think there are multiple right answers, but I have a specific one that I prefer. Applying the same transfer function to all pixels corresponds pretty tightly to film & paper exposure in analog photography. So one reasonable followup question is: did we count manually over- or under-exposing an analog photo to be manipulation or “processing”? Like you can’t see an image without exposing it, so even though there are timing & brightness recommendations for any given film or paper, generally speaking it’s not considered manipulation to expose it until it’s visible. Sometimes if we pushed or pulled to change the way something looks such that you see things that weren’t visible to the naked eye, then we call it manipulation, but generally people aren’t accused of “photoshopping” something just by raising or lowering the brightness a little, right?

When I started reading the article, my first thought was, ‘there’s no such thing as an unprocessed photo that you can see’. Sensor readings can’t be looked at without making choices about how to expose them, without choosing a mapping or transfer function. That’s not to mention that they come with physical response curves that the author went out of his way to sort-of remove. The first few dark images in there are a sort of unnatural way to view images, but in fact they are just as processed as the final image, they’re simply processed differently. You can’t avoid “processing” a digital image if you want to see it, right? Measuring light with sensors involves response curves, transcoding to an image format involves response curves, and displaying on monitor or paper involves response curves, so any image has been processed a bunch by the time we see it, right? Does that count as “processing”? Technically, I think exposure processing is always built-in, but that kinda means exposing an image is natural and not some type of manipulation that changes the image. Ultimately it depends on what we mean by “processing”.

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jjbinx007today at 1:44 AM

Equally bad is the massive over sharpening applied to CCTV and dash cams. I tried to buy a dash cam a year ago that didn't have over sharpened images but it proved impossible.

Reading reg plates would be a lot easier if I could sharpen the image myself rather than try to battle with the "turn it up to 11" approach by manufacturers.

Gibbon1today at 5:18 AM

Was mentioning to my GF (non technical animator) about the submission Clock synchronization is a nightmare. And how it comes up like a bad penny. She said in animation you have the problem that you're animating to match different streams and you have to keep in sync. Bonus you have to dither because if you match too close the players can smell it's off.

Noise is part of the world itself.

erutoday at 1:33 AM

Just wait a few years, all of this is still getting better.

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