Talk:2414: Solar System Compression Artifacts - Revision history

162.158.102.49 at 17:51, 14 April 2022

2022-04-14T17:51:29Z

141.101.104.80 at 23:01, 10 April 2022

2022-04-10T23:01:04Z

Sqrt-1 at 05:33, 27 January 2021

2021-01-27T05:33:35Z

141.101.77.126 at 22:58, 24 January 2021

2021-01-24T22:58:04Z

Efalk at 17:15, 24 January 2021

2021-01-24T17:15:49Z

Efalk: This explainxkcd highlights the fact that Voyager seems to reach one arbitrary milestone after another.

2021-01-24T17:13:31Z

This explainxkcd highlights the fact that Voyager seems to reach one arbitrary milestone after another.

108.162.237.28: edit to previous comment

2021-01-22T16:52:56Z

edit to previous comment

108.162.237.28: explaining dark color banding

2021-01-22T16:50:41Z

explaining dark color banding

108.162.241.70: Noting that this isn't just a problem from the past, and also that the decompression algorithm might be to blame

2021-01-22T13:46:11Z

Noting that this isn't just a problem from the past, and also that the decompression algorithm might be to blame

Walter Eagle: /* Source of Voyager 1 */ new section

2021-01-22T12:53:42Z

‎Source of Voyager 1: new section

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 ::TLDR is this Tom Scott video on the topic: https://youtu.be/h9j89L8eQQk. Short version: the difference between blacks #010101 and #020202 (a doubling of brightness) is more noticeable than the difference between whites #FEFEFE and #FDFDFD (a 0.00001% change in brightness). If your picture is dark, and especially if it is compressed, you will often get ugly bands of different shades of black. [[Special:Contributions/108.162.237.28|108.162.237.28]] 16:50, 22 January 2021 (UTC)
 :::Nice.<span> — [[User:Sqrt-1|The <b>𝗦𝗾𝗿𝘁-𝟭</b>]] <sup>[[User talk:Sqrt-1|<span style="color: blue">talk</span>]] [[Special:Contributions/Sqrt-1|<span style="color: blue">stalk</span>]]</sup></span> 05:33, 27 January 2021 (UTC)
 I would suggest that more emphasis needs to be placed on 'dynamic range' and 'undetectable' in this explanation. Particularly noticeable in streaming video codecs, you often can't decipher any information in dark scenes/regions. So the joke is that the map beyond here is empty, mostly because it is too far down in the dynamic range of our lossy observations. [[Special:Contributions/108.162.219.80|108.162.219.80]] 17:36, 21 January 2021 (UTC)
 :Re "...stretches out over maybe a dozen such low-res pixels/AUs, which is equivalent to slightly more than the radius of Saturn's orbit or the entire diameter of Jupiter's!", this assumes that Jupiter and Voyager are the same distance from the imaginary "camera". I can completely cover the moon with my thumb, but that does not imply that they are similar in size, because my thumb is closer to my eye. ''(Unsigned!)''

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	One more point: I think this XKCD is a play on the fact that every few years we hear once again that "Voyager has left the solar system". First because it passed the termination shock, then because it passed the heliopause. [https://solarsystem.nasa.gov/news/784/nasas-voyager-2-probe-enters-interstellar-space/ This article from NASA] says that Voyager won't be officially out of the solar system until it passes the Oort cloud. These milestones seem arbitrary, so why not make up one more? [[User:Efalk\|Efalk]] ([[User talk:Efalk\|talk]]) 17:13, 24 January 2021 (UTC)		One more point: I think this XKCD is a play on the fact that every few years we hear once again that "Voyager has left the solar system". First because it passed the termination shock, then because it passed the heliopause. [https://solarsystem.nasa.gov/news/784/nasas-voyager-2-probe-enters-interstellar-space/ This article from NASA] says that Voyager won't be officially out of the solar system until it passes the Oort cloud. These milestones seem arbitrary, so why not make up one more? [[User:Efalk\|Efalk]] ([[User talk:Efalk\|talk]]) 17:13, 24 January 2021 (UTC)
		+
		+	== Bit Depth ==
		+	Using the 2x image I've counted the number of grays used by the map and while some are hard to verify, even at the lowest there are more than 16, so it can't be 4-bit compression.--[[Special:Contributions/141.101.104.80\|141.101.104.80]] 23:01, 10 April 2022 (UTC)

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 :tl;dr?<span> — [[User:Sqrt-1|The <b>𝗦𝗾𝗿𝘁-𝟭</b>]] <sup>[[User talk:Sqrt-1|<span style="color: blue">talk</span>]] [[Special:Contributions/Sqrt-1|<span style="color: blue">stalk</span>]]</sup></span> 13:16, 21 January 2021 (UTC)
 ::TLDR is this Tom Scott video on the topic: https://youtu.be/h9j89L8eQQk. Short version: the difference between blacks #010101 and #020202 (a doubling of brightness) is more noticeable than the difference between whites #FEFEFE and #FDFDFD (a 0.00001% change in brightness). If your picture is dark, and especially if it is compressed, you will often get ugly bands of different shades of black. [[Special:Contributions/108.162.237.28|108.162.237.28]] 16:50, 22 January 2021 (UTC)
 I would suggest that more emphasis needs to be placed on 'dynamic range' and 'undetectable' in this explanation. Particularly noticeable in streaming video codecs, you often can't decipher any information in dark scenes/regions. So the joke is that the map beyond here is empty, mostly because it is too far down in the dynamic range of our lossy observations. [[Special:Contributions/108.162.219.80|108.162.219.80]] 17:36, 21 January 2021 (UTC)
 :Re "...stretches out over maybe a dozen such low-res pixels/AUs, which is equivalent to slightly more than the radius of Saturn's orbit or the entire diameter of Jupiter's!", this assumes that Jupiter and Voyager are the same distance from the imaginary "camera". I can completely cover the moon with my thumb, but that does not imply that they are similar in size, because my thumb is closer to my eye. ''(Unsigned!)''

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 I'm not sure dithering would be a useful way to dispel the banding, since dithering would increase the compressed data size because you no longer have large areas of all-the-same-pixel-value.
 The banding could also be an artifact of the decompression. If you consider that a format like JPEG uses something like Fourier transforms it seems it should be able to represent a gradation easily and the stepped banding with difficulty, so I might be tempted to blame the banding on the decompression code.[[Special:Contributions/108.162.241.70|108.162.241.70]] 13:46, 22 January 2021 (UTC)
 == Source of Voyager 1 ==

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	The only sentient creatures who may still care about its origins in the United States are probably also from the United States. The next sentient beings to encounter Voyager 1 will have no understanding of what the United States is or was.		The only sentient creatures who may still care about its origins in the United States are probably also from the United States. The next sentient beings to encounter Voyager 1 will have no understanding of what the United States is or was.

−	One more point: I think this XKCD is a play on the fact that every few years we hear once again that "Voyager has left the solar system". First because it passed the termination shock, then because it passed the heliopause. [~~This article from NASA](~~https://solarsystem.nasa.gov/news/784/nasas-voyager-2-probe-enters-interstellar-space/) says that Voyager won't be officially out of the solar system until it passes the Oort cloud. These milestones seem arbitrary, so why not make up one more? [[User:Efalk\|Efalk]] ([[User talk:Efalk\|talk]]) 17:13, 24 January 2021 (UTC)	+	One more point: I think this XKCD is a play on the fact that every few years we hear once again that "Voyager has left the solar system". First because it passed the termination shock, then because it passed the heliopause. [https://solarsystem.nasa.gov/news/784/nasas-voyager-2-probe-enters-interstellar-space/ This article from NASA] says that Voyager won't be officially out of the solar system until it passes the Oort cloud. These milestones seem arbitrary, so why not make up one more? [[User:Efalk\|Efalk]] ([[User talk:Efalk\|talk]]) 17:13, 24 January 2021 (UTC)

← Older revision		Revision as of 17:13, 24 January 2021
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	Given Voyager 1's distance and age now, wouldn't it be more appropriate to change the opening explanatory sentence to "Voyager 1 is a space probe launched from Earth in 1977."		Given Voyager 1's distance and age now, wouldn't it be more appropriate to change the opening explanatory sentence to "Voyager 1 is a space probe launched from Earth in 1977."
	The only sentient creatures who may still care about its origins in the United States are probably also from the United States. The next sentient beings to encounter Voyager 1 will have no understanding of what the United States is or was.		The only sentient creatures who may still care about its origins in the United States are probably also from the United States. The next sentient beings to encounter Voyager 1 will have no understanding of what the United States is or was.
		+
		+	One more point: I think this XKCD is a play on the fact that every few years we hear once again that "Voyager has left the solar system". First because it passed the termination shock, then because it passed the heliopause. [This article from NASA](https://solarsystem.nasa.gov/news/784/nasas-voyager-2-probe-enters-interstellar-space/) says that Voyager won't be officially out of the solar system until it passes the Oort cloud. These milestones seem arbitrary, so why not make up one more? [[User:Efalk\|Efalk]] ([[User talk:Efalk\|talk]]) 17:13, 24 January 2021 (UTC)

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 :Re: "The Voyager image (and track) is overlaid at finer resolution", if it not unheard-of for a compression algorithm to render, say, 32x32 pixel blocks as if they were single, larger pixels if their immediate neighbors are almost the same shade, while rendering small, detailed, and high contrast portions of the image at a higher resolution. No "overlay" required. ''(Still unsigned!)''
 ::Within an area of finer details, artefacts ''would'' be seen as the "meh, this is just one block" attitude is changed to incorperate detail of interest within a sub-block. There's no sign of fringe-artefacts (other than normal XKCS antialiasing of lines against background). I'd say it was a "solar wind" low-detail layer over which is incorporated a "Voyager" standard-detail layer with transparency, not a single layer of subject-aware tunable blockwise compression. (It might have come out differently if the composition was saved in an actual lossy-compression, by Randall, rather than .png, but for different reasons. Bit that's a meta-discussion issue, not nerd-sniping.) [[Special:Contributions/141.101.104.241|141.101.104.241]] 01:18, 22 January 2021 (UTC)
 == Source of Voyager 1 ==

← Older revision		Revision as of 12:53, 22 January 2021
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	:Re: "The Voyager image (and track) is overlaid at finer resolution", if it not unheard-of for a compression algorithm to render, say, 32x32 pixel blocks as if they were single, larger pixels if their immediate neighbors are almost the same shade, while rendering small, detailed, and high contrast portions of the image at a higher resolution. No "overlay" required. ''(Still unsigned!)''		:Re: "The Voyager image (and track) is overlaid at finer resolution", if it not unheard-of for a compression algorithm to render, say, 32x32 pixel blocks as if they were single, larger pixels if their immediate neighbors are almost the same shade, while rendering small, detailed, and high contrast portions of the image at a higher resolution. No "overlay" required. ''(Still unsigned!)''
	::Within an area of finer details, artefacts ''would'' be seen as the "meh, this is just one block" attitude is changed to incorperate detail of interest within a sub-block. There's no sign of fringe-artefacts (other than normal XKCS antialiasing of lines against background). I'd say it was a "solar wind" low-detail layer over which is incorporated a "Voyager" standard-detail layer with transparency, not a single layer of subject-aware tunable blockwise compression. (It might have come out differently if the composition was saved in an actual lossy-compression, by Randall, rather than .png, but for different reasons. Bit that's a meta-discussion issue, not nerd-sniping.) [[Special:Contributions/141.101.104.241\|141.101.104.241]] 01:18, 22 January 2021 (UTC)		::Within an area of finer details, artefacts ''would'' be seen as the "meh, this is just one block" attitude is changed to incorperate detail of interest within a sub-block. There's no sign of fringe-artefacts (other than normal XKCS antialiasing of lines against background). I'd say it was a "solar wind" low-detail layer over which is incorporated a "Voyager" standard-detail layer with transparency, not a single layer of subject-aware tunable blockwise compression. (It might have come out differently if the composition was saved in an actual lossy-compression, by Randall, rather than .png, but for different reasons. Bit that's a meta-discussion issue, not nerd-sniping.) [[Special:Contributions/141.101.104.241\|141.101.104.241]] 01:18, 22 January 2021 (UTC)
		+
		+	== Source of Voyager 1 ==
		+
		+	Given Voyager 1's distance and age now, wouldn't it be more appropriate to change the opening explanatory sentence to "Voyager 1 is a space probe launched from Earth in 1977."
		+	The only sentient creatures who may still care about its origins in the United States are probably also from the United States. The next sentient beings to encounter Voyager 1 will have no understanding of what the United States is or was.