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Is this the same as "HSB" (which Photoshop uses)? -- Tarquin
Are you sure that V = min(R, G, B) is correct? If correct, bright red would have V = 0 but bright white would have V = <max>: this seems wrong.
Good job fixing these equations; I was actually mixed up by the max/min error when I looked at this page just last week! Just returned to fix it now that I've figured it out and now that I have a user account, but you already did it :).
I think we need to fix the parts at the top that say "Measured in values of ... by the ... wavelength". I don't think this is really the right way to talk about HSV; HSV isn't ever really "measured", like you wouldn't take your spectrometer and try to read off HSV values from it. HSV is generative; you specify it and then your computer or other device generates some wavelengths to approximate your specifications. The parameters of HSV don't really correspond to any physical properties like wavelength though, except so far as your computer screen is able to translate them, which differs from screen to screen. Anyway, the current description as the "amplitude", "spread", etc. of wavelength are certainly not right. I'll fix these sometime soon if I can find time to come up with a more correct description. Unless someone tells me I don't know what I'm talking about (I think I do...).
-- Chinasaur 09:45, Feb 27, 2004 (UTC)
I think I understand now what the "amplitude" and "spread" descriptions are trying to talk about, but they were backwards in the version I edited.
Saturation can sort of be thought of as the spread of the power spectrum, except that it is an inverse relationship; if you were looking at a narrow band of pure spectral color, that would correspond to a narrow band in physical frequency space. As you spread the frequency space band, the color would begin to appear washed out (hue might also shift a bit though), i.e. saturation would decrease.
Likewise, amplitude in the frequency domain (or time domain, but thinking spectrally makes more sense) is an okay analogy to HSV Value, although Value is not actually very cleanly related to radiant intensity (e.g. radiant intensity clearly increases as you desaturate a color, but HSV Value doesn't change in this case), or even psychophysical luminance (which I think is represented in CIE XYZ by Y).
So I'll probably put back at least the spread idea (but for Saturation, not Value). The amplitude idea is not very clean, plus confusing since amplitude is usually a wave property and that's a bad way to think about non-spectrally-pure colors. Plus understanding Value as max(RGB) is simple and doesn't seem to need a better intuitive analogy, while delta/max for Saturation might not give an obvious intuition so the spread idea is probably worth giving.
-- Chinasaur 00:39, Feb 28, 2004 (UTC)
Actually, mathematically it makes more sense to describe the HSV space as a cylinder instead of a cone. After all, the allowed range of the saturation parameter does not decrease when the value is decreased. -- Hankwang 20:07, 6 Mar 2004 (UTC)
IP 128.174.154.152 (ctl22.lis.uiuc.edu, apparently someone from University of Illinois at Urbana-Champaign) blanked the page this evening. There was no note of explanation or evidence of a page move, so I reverted to the previous edit.
Chinasaur 05:26, Mar 17, 2004 (UTC)
Requesting peer review of dominant wavelength -- Chinasaur 18:39, Mar 19, 2004 (UTC)
see: User:Kim Bruning/colorspace.py
When then , and hence , so that each of the calculations for h is a division by 0.
if MAX=0, then V=0 , and calculating S is a division by 0.
let's see... hmm, so putting that better:
Okay, I've fixed the programme to deal with it:-)
Kim Bruning 20:43, 6 Apr 2004 (UTC)
Nooope, wait, it's STILL wrong if any of
Then the formula is undecided again, since there are 2 possible values for H!
Found out while trying to make up a color for yellow :-/
Okay, I have no clue if there's a mathemagical way to deal with that, but the formula here is really quite tricky to code ^^;; I'll ask for peer review.
Kim Bruning 21:05, 6 Apr 2004 (UTC)
Here's a slightly different formula: http://www.easyrgb.com/math.php?MATH=M20#text20 Kim Bruning 21:19, 6 Apr 2004 (UTC)
Fixed the progamme! All hail and thanks to
Chinasaur for helping me with both the formula, and the code! :-)
Kim Bruning 14:59, 7 Apr 2004 (UTC)
Good idea; it's nice and concise. My math is poor, though; would one still obtain saturation and value in the same way (since those are preliminary to finding hue)? The hue article doesn't explain the range of μ and σ (is it again between 0.0 and 1.0?) -- Wapcaplet 23:57, 31 Dec 2004 (UTC)
On HSV color space#Transformation from HSV to RGB. The six results for Hi use a variable v (small letter, italic). This variable is not present in de formulas above, ie is is unknown & has no value when used in Hi's. I think this is not correct. First thing I expect (fwiw): if six H's are possible, thats the six sequence-combinations of p, q, t. User:DePiep 14:45, 24 May 2005 (UTC)
On
HSV color space#Transformation from HSV to RGB.
The outcome makes an pre-exeption for when S=0 (no hue). For just above the maths it states: When S is non-zero, the following formulas can be used.
To me it seems that the functions can also be used when S=0 (no risk of division-by-zero). Is it more correct, then, to put the S=0 remark afterwards, as an illusttration (and not an part of the formulas). -
DePiep
14:52, 24 May 2005 (UTC)
See the part
HSV color space#Transformation from RGB to HSV.
Here I expect the S=0-situation to be mentioned before the H-formulas, since that does introduce a division-by-zero possibility. Isn't it more maths & logic to create a one-way route throught the formulas? -
DePiep
15:00, 24 May 2005 (UTC)
Is it possible to represent the HSV colour space as a sphere, where value corresponds to latitude, hue corresponds to longitude, and saturation corresponds to distance from the centre of the sphere? Denelson 83 04:57, 29 October 2005 (UTC)
Since hue is an angle on the colour wheel thinger, it is measured in either an angle (0.0°–360.0°) or a percentage (0.0%–100.0%). However, most mathematicians (and physicists) tend to use radians (0–2π) as a linear method of angle measurement. I don't know if the HSV specs allow for angles to be supplied in radians, but I think the article should mention something regarding angles being measured in degrees and not in any other angular measurement. I know it might seem somewhat esoteric, but it confused me at first when I read the equations.
Article says:
First, if S is equal to 0.0, then the resulting color is achromatic, or grey. In this special case, R, G, and B are simply equal to V. As above, H is irrelevant in this situation. When S is non-zero, the following formulas can be used:
But the formulas seem to work fine in the special case — there's no division by S, and p, q, t, R, G, and B all get set to V in all cases. Deco 05:57, 12 May 2006 (UTC)
Perhaps my math is lacking, but why does the transformation to RGB over at Hue differ from that listed in this article? The one in this article appears to work, but I have not managed to get the one at Hue to work. I may just be misinterpreting it, though. Could someone clear this up? Thanks. -- Orborde 03:49, 25 June 2006 (UTC)
The arrows in the image Image:HSV_clr_whl.png are wrong. The current image implies incorrectly that you cannot change "V" when "S" is at maximum. It also implies that with V at minimum you could change the color by changing S which is also wrong. Instead, the S arrow should go from total white to totally saturated green and the V arrow should start at total black and be orthogonal to the S arrow. - Oxygene123 11:43, 10 October 2006 (UTC)
Just wanted to add that I agree with the above, and was just about to post the same comment when I saw this. The S arrow should be parallel with the top-right triangle edge going from white to green, and the V arrow should be perpendicular to it from the black corner to the .5-saturated green in the center of the top-right edge. - User:Spitzak
After pondering this and reading a shitton about different color spaces, I think that the cylindrical and conical images of HSV are incorrect. Both are sliced at the 50% mark in the V direction, the V value in the middle of the cylinder or cone should be grey and the cylinder or cone should go back up to white (it is black at the bottom). Maybe this was implied by the images but if so it should be stated in the descriptions or text Jackkoho 19:55, 2 January 2007 (UTC)
Why this is markes as unreferenced if there is a reference at the bottom? is that reference wrong or the signal should be removed? -- Samus uy 00:07, 23 October 2006 (UTC)
The HSL article states that HSV and HSL are different. Which article is correct? - SharkD 08:23, 23 October 2006 (UTC)
Speaking as a somewhat educated layman on the issues who's just checking in to remind himself of a few things, I think the article's good -- I was able to refresh my memory on the important points -- but I find the animated color space images extremely irritating. They totally disrupt the experience of trying to read through or refer to the page, without any significant benefit. It would be more appropriate to link to the images, or better yet display or link to an image that lets you manually control your view of the color space. As it is, having the page open makes me feel like I'm standing on one of those Saturday Night Fever dancefloors... not helpful to the design process.
Also, the "chart" section for viewing "precisely the effect of varying levels" could use expansion. I know a fair bit about HSV-vs-RGB-vs-YUV and so on, and it still took me a few minutes and a bunch of looking up and down to grasp what's going on in these illustrations. The average reader is not going to learn anything.
-- Anonymous non-wiki-guy —The preceding unsigned comment was added by 66.93.144.192 ( talk) 03:54, 8 January 2007 (UTC).
Does anyone else support the removal of the animated images? I do not believe they add much to the article and are very distracting from the textual content. Alternatively, replace with static images? ChrisRBennett 01:23, 15 August 2007 (UTC)
I would support removing them; they appear to be redundant. Alternatively, I might be able to tolerate one animated image that's not too flashy, but not multiple ones. Dicklyon 02:36, 15 August 2007 (UTC)
I added the "hueborhood" image and description to the bottom of the section. The new image kept causing layout problems as the system kept trying to figure what image goes where and with what text. The only way I could figure out to halfway keep the set of two images interacting with the new one was to add subcategories. It's not an ideal solution; if a wiki expert can figure out some other way, it would be great. Thanks. 2*6 14:02, 10 January 2007 (UTC)
Hello (:-) 11 01 2007 The figures right page 1, 2 and 3*3* Hue Neighborhood page 3 and right page 5 Are not printed
Vidiani (Dijon)
—The preceding unsigned comment was added by 89.85.64.106 ( talk) 10:28, 11 January 2007 (UTC).
The text:
Certain RGB colors have no integer HSV representation. In fact, only 1/256th of the RGB colors are 'available' in HSV, effectively eliminating a single channel of control from the graphics artist.
is wrong. My, not particularly smart, implementation of the HSV color space reduced the total 16 millions colors to about 7.5 millions. That is around 45% of the original number, but definitely more than 1/256th. -- Prydeson 22:36, 8 February 2007 (UTC)
http://www.cs.rit.edu/~ncs/color/t_convert.html
The case switching on Hi{0,1,2,3,4,5} should actually be switching on f, no? See above reference.
Please take a look at Luminance-Hue-Saturation as it probably needs a bit of work (I am not the author, I just moved it). Thanks! Fourohfour 13:48, 22 July 2007 (UTC)
Excuse my ignorance but could someone please check that the illustration on the left is saturation not intensity? Maybe explain how it was genenerated? 130.130.37.12 01:14, 4 September 2007 (UTC) harryh
![]() | HSV color space received a peer review by Wikipedia editors, which is now archived. It may contain ideas you can use to improve this article. |
![]() | This is the
talk page of a
redirect that targets the page: • HSL and HSV Because this page is not frequently watched, present and future discussions, edit requests and requested moves should take place at: • Talk:HSL and HSV |
![]() | This redirect does not require a rating on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | ||||||||||
|
Is this the same as "HSB" (which Photoshop uses)? -- Tarquin
Are you sure that V = min(R, G, B) is correct? If correct, bright red would have V = 0 but bright white would have V = <max>: this seems wrong.
Good job fixing these equations; I was actually mixed up by the max/min error when I looked at this page just last week! Just returned to fix it now that I've figured it out and now that I have a user account, but you already did it :).
I think we need to fix the parts at the top that say "Measured in values of ... by the ... wavelength". I don't think this is really the right way to talk about HSV; HSV isn't ever really "measured", like you wouldn't take your spectrometer and try to read off HSV values from it. HSV is generative; you specify it and then your computer or other device generates some wavelengths to approximate your specifications. The parameters of HSV don't really correspond to any physical properties like wavelength though, except so far as your computer screen is able to translate them, which differs from screen to screen. Anyway, the current description as the "amplitude", "spread", etc. of wavelength are certainly not right. I'll fix these sometime soon if I can find time to come up with a more correct description. Unless someone tells me I don't know what I'm talking about (I think I do...).
-- Chinasaur 09:45, Feb 27, 2004 (UTC)
I think I understand now what the "amplitude" and "spread" descriptions are trying to talk about, but they were backwards in the version I edited.
Saturation can sort of be thought of as the spread of the power spectrum, except that it is an inverse relationship; if you were looking at a narrow band of pure spectral color, that would correspond to a narrow band in physical frequency space. As you spread the frequency space band, the color would begin to appear washed out (hue might also shift a bit though), i.e. saturation would decrease.
Likewise, amplitude in the frequency domain (or time domain, but thinking spectrally makes more sense) is an okay analogy to HSV Value, although Value is not actually very cleanly related to radiant intensity (e.g. radiant intensity clearly increases as you desaturate a color, but HSV Value doesn't change in this case), or even psychophysical luminance (which I think is represented in CIE XYZ by Y).
So I'll probably put back at least the spread idea (but for Saturation, not Value). The amplitude idea is not very clean, plus confusing since amplitude is usually a wave property and that's a bad way to think about non-spectrally-pure colors. Plus understanding Value as max(RGB) is simple and doesn't seem to need a better intuitive analogy, while delta/max for Saturation might not give an obvious intuition so the spread idea is probably worth giving.
-- Chinasaur 00:39, Feb 28, 2004 (UTC)
Actually, mathematically it makes more sense to describe the HSV space as a cylinder instead of a cone. After all, the allowed range of the saturation parameter does not decrease when the value is decreased. -- Hankwang 20:07, 6 Mar 2004 (UTC)
IP 128.174.154.152 (ctl22.lis.uiuc.edu, apparently someone from University of Illinois at Urbana-Champaign) blanked the page this evening. There was no note of explanation or evidence of a page move, so I reverted to the previous edit.
Chinasaur 05:26, Mar 17, 2004 (UTC)
Requesting peer review of dominant wavelength -- Chinasaur 18:39, Mar 19, 2004 (UTC)
see: User:Kim Bruning/colorspace.py
When then , and hence , so that each of the calculations for h is a division by 0.
if MAX=0, then V=0 , and calculating S is a division by 0.
let's see... hmm, so putting that better:
Okay, I've fixed the programme to deal with it:-)
Kim Bruning 20:43, 6 Apr 2004 (UTC)
Nooope, wait, it's STILL wrong if any of
Then the formula is undecided again, since there are 2 possible values for H!
Found out while trying to make up a color for yellow :-/
Okay, I have no clue if there's a mathemagical way to deal with that, but the formula here is really quite tricky to code ^^;; I'll ask for peer review.
Kim Bruning 21:05, 6 Apr 2004 (UTC)
Here's a slightly different formula: http://www.easyrgb.com/math.php?MATH=M20#text20 Kim Bruning 21:19, 6 Apr 2004 (UTC)
Fixed the progamme! All hail and thanks to
Chinasaur for helping me with both the formula, and the code! :-)
Kim Bruning 14:59, 7 Apr 2004 (UTC)
Good idea; it's nice and concise. My math is poor, though; would one still obtain saturation and value in the same way (since those are preliminary to finding hue)? The hue article doesn't explain the range of μ and σ (is it again between 0.0 and 1.0?) -- Wapcaplet 23:57, 31 Dec 2004 (UTC)
On HSV color space#Transformation from HSV to RGB. The six results for Hi use a variable v (small letter, italic). This variable is not present in de formulas above, ie is is unknown & has no value when used in Hi's. I think this is not correct. First thing I expect (fwiw): if six H's are possible, thats the six sequence-combinations of p, q, t. User:DePiep 14:45, 24 May 2005 (UTC)
On
HSV color space#Transformation from HSV to RGB.
The outcome makes an pre-exeption for when S=0 (no hue). For just above the maths it states: When S is non-zero, the following formulas can be used.
To me it seems that the functions can also be used when S=0 (no risk of division-by-zero). Is it more correct, then, to put the S=0 remark afterwards, as an illusttration (and not an part of the formulas). -
DePiep
14:52, 24 May 2005 (UTC)
See the part
HSV color space#Transformation from RGB to HSV.
Here I expect the S=0-situation to be mentioned before the H-formulas, since that does introduce a division-by-zero possibility. Isn't it more maths & logic to create a one-way route throught the formulas? -
DePiep
15:00, 24 May 2005 (UTC)
Is it possible to represent the HSV colour space as a sphere, where value corresponds to latitude, hue corresponds to longitude, and saturation corresponds to distance from the centre of the sphere? Denelson 83 04:57, 29 October 2005 (UTC)
Since hue is an angle on the colour wheel thinger, it is measured in either an angle (0.0°–360.0°) or a percentage (0.0%–100.0%). However, most mathematicians (and physicists) tend to use radians (0–2π) as a linear method of angle measurement. I don't know if the HSV specs allow for angles to be supplied in radians, but I think the article should mention something regarding angles being measured in degrees and not in any other angular measurement. I know it might seem somewhat esoteric, but it confused me at first when I read the equations.
Article says:
First, if S is equal to 0.0, then the resulting color is achromatic, or grey. In this special case, R, G, and B are simply equal to V. As above, H is irrelevant in this situation. When S is non-zero, the following formulas can be used:
But the formulas seem to work fine in the special case — there's no division by S, and p, q, t, R, G, and B all get set to V in all cases. Deco 05:57, 12 May 2006 (UTC)
Perhaps my math is lacking, but why does the transformation to RGB over at Hue differ from that listed in this article? The one in this article appears to work, but I have not managed to get the one at Hue to work. I may just be misinterpreting it, though. Could someone clear this up? Thanks. -- Orborde 03:49, 25 June 2006 (UTC)
The arrows in the image Image:HSV_clr_whl.png are wrong. The current image implies incorrectly that you cannot change "V" when "S" is at maximum. It also implies that with V at minimum you could change the color by changing S which is also wrong. Instead, the S arrow should go from total white to totally saturated green and the V arrow should start at total black and be orthogonal to the S arrow. - Oxygene123 11:43, 10 October 2006 (UTC)
Just wanted to add that I agree with the above, and was just about to post the same comment when I saw this. The S arrow should be parallel with the top-right triangle edge going from white to green, and the V arrow should be perpendicular to it from the black corner to the .5-saturated green in the center of the top-right edge. - User:Spitzak
After pondering this and reading a shitton about different color spaces, I think that the cylindrical and conical images of HSV are incorrect. Both are sliced at the 50% mark in the V direction, the V value in the middle of the cylinder or cone should be grey and the cylinder or cone should go back up to white (it is black at the bottom). Maybe this was implied by the images but if so it should be stated in the descriptions or text Jackkoho 19:55, 2 January 2007 (UTC)
Why this is markes as unreferenced if there is a reference at the bottom? is that reference wrong or the signal should be removed? -- Samus uy 00:07, 23 October 2006 (UTC)
The HSL article states that HSV and HSL are different. Which article is correct? - SharkD 08:23, 23 October 2006 (UTC)
Speaking as a somewhat educated layman on the issues who's just checking in to remind himself of a few things, I think the article's good -- I was able to refresh my memory on the important points -- but I find the animated color space images extremely irritating. They totally disrupt the experience of trying to read through or refer to the page, without any significant benefit. It would be more appropriate to link to the images, or better yet display or link to an image that lets you manually control your view of the color space. As it is, having the page open makes me feel like I'm standing on one of those Saturday Night Fever dancefloors... not helpful to the design process.
Also, the "chart" section for viewing "precisely the effect of varying levels" could use expansion. I know a fair bit about HSV-vs-RGB-vs-YUV and so on, and it still took me a few minutes and a bunch of looking up and down to grasp what's going on in these illustrations. The average reader is not going to learn anything.
-- Anonymous non-wiki-guy —The preceding unsigned comment was added by 66.93.144.192 ( talk) 03:54, 8 January 2007 (UTC).
Does anyone else support the removal of the animated images? I do not believe they add much to the article and are very distracting from the textual content. Alternatively, replace with static images? ChrisRBennett 01:23, 15 August 2007 (UTC)
I would support removing them; they appear to be redundant. Alternatively, I might be able to tolerate one animated image that's not too flashy, but not multiple ones. Dicklyon 02:36, 15 August 2007 (UTC)
I added the "hueborhood" image and description to the bottom of the section. The new image kept causing layout problems as the system kept trying to figure what image goes where and with what text. The only way I could figure out to halfway keep the set of two images interacting with the new one was to add subcategories. It's not an ideal solution; if a wiki expert can figure out some other way, it would be great. Thanks. 2*6 14:02, 10 January 2007 (UTC)
Hello (:-) 11 01 2007 The figures right page 1, 2 and 3*3* Hue Neighborhood page 3 and right page 5 Are not printed
Vidiani (Dijon)
—The preceding unsigned comment was added by 89.85.64.106 ( talk) 10:28, 11 January 2007 (UTC).
The text:
Certain RGB colors have no integer HSV representation. In fact, only 1/256th of the RGB colors are 'available' in HSV, effectively eliminating a single channel of control from the graphics artist.
is wrong. My, not particularly smart, implementation of the HSV color space reduced the total 16 millions colors to about 7.5 millions. That is around 45% of the original number, but definitely more than 1/256th. -- Prydeson 22:36, 8 February 2007 (UTC)
http://www.cs.rit.edu/~ncs/color/t_convert.html
The case switching on Hi{0,1,2,3,4,5} should actually be switching on f, no? See above reference.
Please take a look at Luminance-Hue-Saturation as it probably needs a bit of work (I am not the author, I just moved it). Thanks! Fourohfour 13:48, 22 July 2007 (UTC)
Excuse my ignorance but could someone please check that the illustration on the left is saturation not intensity? Maybe explain how it was genenerated? 130.130.37.12 01:14, 4 September 2007 (UTC) harryh