Software to find (and possibly remove/map out) hot pixels in image?

[sirhawkeye64]

Is there a plug-in for PS or LR that can map out hot pixels or at least allow you to quickly find them in an image (particularly ones that appear as white on a darker background, like a night sky or dark wall, etc?

I'm noticing more and more on my Z7 II long exposures (anything over about 10 seconds) and have already done some preliminary tests and some other measures to reduce them (sensor cleaning a few times, and then a pixel mapping, which has taken care of most of them) but I suspect this will be an ongoing issue moving forward since it seems to creep up from time to time for many people (or in some people's cases, all the time with LR).

So I've taken the measures I can think of to reduce them at the time of capture (including enabling LE NR).

I have PL5 and thought their Dead Pixel removal function would also take care of hot pixels, but it doesn't seem to in many cases (as I think it's looking for just a single pixel but my hot pixels appear in 3's --- 3 pixels in a row either vertical or horizontal and in some cases as many as a block of 6, but they are hot pixels as I've determined as they aren't necessarily the same from image to image, which also makes removing and identifying them more challening.

I also though in older version of LR Classic it also mapped out (during import) hot pixels it finds, but it seems that it maybe doesn't (at least in the more current versions)?

Suggestions? I do a lot of long exposures and in some cases, the hot pixels end up in areas that are pretty easy to deal with, sometimes it's just a few (primarily in shadow areas where it probably doesn't matter), other times there's several.

 

[sybersitizen]

I have PL5 and thought their Dead Pixel removal function would also take care of hot pixels, but it doesn't seem to in many cases (as I think it's looking for just a single pixel but my hot pixels appear in 3's --- 3 pixels in a row either vertical or horizontal and in some cases as many as a block of 6, but they are hot pixels as I've determined as they aren't necessarily the same from image to image, which also makes removing and identifying them more challening.

I also though in older version of LR Classic it also mapped out (during import) hot pixels it finds, but it seems that it maybe doesn't (at least in the more current versions)?

If those tools aren't taking care of the problem, I doubt any software that does 'automatic' removal can.

You could try your own dark frame subtraction. Take an extra exposure with the lens cap on, matching the shutter speed and ISO of the actual exposure. Then use software to 'subtract' whatever turned up in the dark frame. This is basically what the in-camera pixel mapping and LENR is supposed to do, but maybe doing it yourself would work better.

 

[Major Jack]

Is there a plug-in for PS or LR that can map out hot pixels or at least allow you to quickly find them in an image (particularly ones that appear as white on a darker background, like a night sky or dark wall, etc?

I'm noticing more and more on my Z7 II long exposures (anything over about 10 seconds) and have already done some preliminary tests and some other measures to reduce them (sensor cleaning a few times, and then a pixel mapping, which has taken care of most of them) but I suspect this will be an ongoing issue moving forward since it seems to creep up from time to time for many people (or in some people's cases, all the time with LR).

So I've taken the measures I can think of to reduce them at the time of capture (including enabling LE NR).

I have PL5 and thought their Dead Pixel removal function would also take care of hot pixels, but it doesn't seem to in many cases (as I think it's looking for just a single pixel but my hot pixels appear in 3's --- 3 pixels in a row either vertical or horizontal and in some cases as many as a block of 6, but they are hot pixels as I've determined as they aren't necessarily the same from image to image, which also makes removing and identifying them more challening.

I also though in older version of LR Classic it also mapped out (during import) hot pixels it finds, but it seems that it maybe doesn't (at least in the more current versions)?

Suggestions? I do a lot of long exposures and in some cases, the hot pixels end up in areas that are pretty easy to deal with, sometimes it's just a few (primarily in shadow areas where it probably doesn't matter), other times there's several.

Photoshop has the Dust and Scratches filter that takes care of any hot pixel issues.

An easy way to see what it does, is to create a black file, and then put several white dots on the black file. Make them very small and then zoom in to see them.

Then to to Filter>Noise>Dust and Scratches. Set the Radius to 1 and Threshold to 0. Hit enter. Poof, they are gone. Now, for slightly larger hot spots, simply increase the radius to 2, 3, 4 etc. Poof, they are gone.

 

[sirhawkeye64]

Is there a plug-in for PS or LR that can map out hot pixels or at least allow you to quickly find them in an image (particularly ones that appear as white on a darker background, like a night sky or dark wall, etc?

I'm noticing more and more on my Z7 II long exposures (anything over about 10 seconds) and have already done some preliminary tests and some other measures to reduce them (sensor cleaning a few times, and then a pixel mapping, which has taken care of most of them) but I suspect this will be an ongoing issue moving forward since it seems to creep up from time to time for many people (or in some people's cases, all the time with LR).

So I've taken the measures I can think of to reduce them at the time of capture (including enabling LE NR).

I have PL5 and thought their Dead Pixel removal function would also take care of hot pixels, but it doesn't seem to in many cases (as I think it's looking for just a single pixel but my hot pixels appear in 3's --- 3 pixels in a row either vertical or horizontal and in some cases as many as a block of 6, but they are hot pixels as I've determined as they aren't necessarily the same from image to image, which also makes removing and identifying them more challening.

I also though in older version of LR Classic it also mapped out (during import) hot pixels it finds, but it seems that it maybe doesn't (at least in the more current versions)?

Suggestions? I do a lot of long exposures and in some cases, the hot pixels end up in areas that are pretty easy to deal with, sometimes it's just a few (primarily in shadow areas where it probably doesn't matter), other times there's several.

Photoshop has the Dust and Scratches filter that takes care of any hot pixel issues.

An easy way to see what it does, is to create a black file, and then put several white dots on the black file. Make them very small and then zoom in to see them.

Then to to Filter>Noise>Dust and Scratches. Set the Radius to 1 and Threshold to 0. Hit enter. Poof, they are gone. Now, for slightly larger hot spots, simply increase the radius to 2, 3, 4 etc. Poof, they are gone.

Thanks. I did find this method online (on Youtube) and have been using it, but it does require me to scan the entire image (visually) to make sure that they are taken care of. Of course in large areas with little or no texture, I can go a bit faster (such as dark shadow areas or areas that are mostly black, as they stand out quite well against dark backgrounds so i can mask those out quickly).

I was just sort of hoping to find a way to perhaps automate the process a bit more since some images seem to have a lot of hot pixels and more than others.

 

[Major Jack]

Is there a plug-in for PS or LR that can map out hot pixels or at least allow you to quickly find them in an image (particularly ones that appear as white on a darker background, like a night sky or dark wall, etc?

I'm noticing more and more on my Z7 II long exposures (anything over about 10 seconds) and have already done some preliminary tests and some other measures to reduce them (sensor cleaning a few times, and then a pixel mapping, which has taken care of most of them) but I suspect this will be an ongoing issue moving forward since it seems to creep up from time to time for many people (or in some people's cases, all the time with LR).

So I've taken the measures I can think of to reduce them at the time of capture (including enabling LE NR).

I have PL5 and thought their Dead Pixel removal function would also take care of hot pixels, but it doesn't seem to in many cases (as I think it's looking for just a single pixel but my hot pixels appear in 3's --- 3 pixels in a row either vertical or horizontal and in some cases as many as a block of 6, but they are hot pixels as I've determined as they aren't necessarily the same from image to image, which also makes removing and identifying them more challening.

I also though in older version of LR Classic it also mapped out (during import) hot pixels it finds, but it seems that it maybe doesn't (at least in the more current versions)?

Suggestions? I do a lot of long exposures and in some cases, the hot pixels end up in areas that are pretty easy to deal with, sometimes it's just a few (primarily in shadow areas where it probably doesn't matter), other times there's several.

Photoshop has the Dust and Scratches filter that takes care of any hot pixel issues.

An easy way to see what it does, is to create a black file, and then put several white dots on the black file. Make them very small and then zoom in to see them.

Then to to Filter>Noise>Dust and Scratches. Set the Radius to 1 and Threshold to 0. Hit enter. Poof, they are gone. Now, for slightly larger hot spots, simply increase the radius to 2, 3, 4 etc. Poof, they are gone.

Thanks. I did find this method online (on Youtube) and have been using it, but it does require me to scan the entire image (visually) to make sure that they are taken care of. Of course in large areas with little or no texture, I can go a bit faster (such as dark shadow areas or areas that are mostly black, as they stand out quite well against dark backgrounds so i can mask those out quickly).

I was just sort of hoping to find a way to perhaps automate the process a bit more since some images seem to have a lot of hot pixels and more than others.

Yeah, it is not a perfect solution. I use it quite a bit on scanned images, and it does a decent job, but not perfect.

 

[Kameratrollet]

I have PL5 and thought their Dead Pixel removal function would also take care of hot pixels, but it doesn't seem to in many cases (as I think it's looking for just a single pixel but my hot pixels appear in 3's --- 3 pixels in a row either vertical or horizontal and in some cases as many as a block of 6, but they are hot pixels as I've determined as they aren't necessarily the same from image to image, which also makes removing and identifying them more challening.

 

[sirhawkeye64]

I have PL5 and thought their Dead Pixel removal function would also take care of hot pixels, but it doesn't seem to in many cases (as I think it's looking for just a single pixel but my hot pixels appear in 3's --- 3 pixels in a row either vertical or horizontal and in some cases as many as a block of 6, but they are hot pixels as I've determined as they aren't necessarily the same from image to image, which also makes removing and identifying them more challening.

Have you checked your raw file before demosaicing?

No. How would I go about doing this? Should I try opening them in a program like NX Studio perhaps (Nikon's RAW editor).

I've only really used Adobe products (so we'll just say the DNG converter as I believe that's at the heart of LR/ACR/Photoshop when it comes to deal with RAWs) and DXO Photolab (both give the same result basically in terms of final image output as it relates to hot pixels, etc so I don't see a difference there).

--
NOTE: If I don't reply to a direct comment in the forums, it's likely I unsubscribed from the thread/article..

 

[Kameratrollet]

I have PL5 and thought their Dead Pixel removal function would also take care of hot pixels, but it doesn't seem to in many cases (as I think it's looking for just a single pixel but my hot pixels appear in 3's --- 3 pixels in a row either vertical or horizontal and in some cases as many as a block of 6, but they are hot pixels as I've determined as they aren't necessarily the same from image to image, which also makes removing and identifying them more challening.

Have you checked your raw file before demosaicing?

No. How would I go about doing this? Should I try opening them in a program like NX Studio perhaps (Nikon's RAW editor).

I've only really used Adobe products (so we'll just say the DNG converter as I believe that's at the heart of LR/ACR/Photoshop when it comes to deal with RAWs) and DXO Photolab (both give the same result basically in terms of final image output as it relates to hot pixels, etc so I don't see a difference there).

--
NOTE: If I don't reply to a direct comment in the forums, it's likely I unsubscribed from the thread/article..

You can do it with Libraw, RawTherapee, dcraw (if you convert to DNG first) or darktable.

In darktable, open your raw file, go to darkroom, active modules and find the module Demosaic. Change to debug or CFA. Now you can see the individual pixels. When you wrote three it is more likely only one. I wonder if I ever seen three in a row or line?







In darktable there is also a hot pixel module you can use to see the pixels better or to remove them.

Adobe removes bad pixels automatically before demosaicing, but there is no threshold slider. If the picture is already demosaiced, like JPEG or DNG from PureRAW, it will not work.

 

[sirhawkeye64]

I have PL5 and thought their Dead Pixel removal function would also take care of hot pixels, but it doesn't seem to in many cases (as I think it's looking for just a single pixel but my hot pixels appear in 3's --- 3 pixels in a row either vertical or horizontal and in some cases as many as a block of 6, but they are hot pixels as I've determined as they aren't necessarily the same from image to image, which also makes removing and identifying them more challening.

Have you checked your raw file before demosaicing?

No. How would I go about doing this? Should I try opening them in a program like NX Studio perhaps (Nikon's RAW editor).

I've only really used Adobe products (so we'll just say the DNG converter as I believe that's at the heart of LR/ACR/Photoshop when it comes to deal with RAWs) and DXO Photolab (both give the same result basically in terms of final image output as it relates to hot pixels, etc so I don't see a difference there).

You can do it with Libraw, RawTherapee, dcraw (if you convert to DNG first) or darktable.

In darktable, open your raw file, go to darkroom, active modules and find the module Demosaic. Change to debug or CFA. Now you can see the individual pixels. When you wrote three it is more likely only one. I wonder if I ever seen three in a row or line?



In darktable there is also a hot pixel module you can use to see the pixels better or to remove them.

Adobe removes bad pixels automatically before demosaicing, but there is no threshold slider. If the picture is already demosaiced, like JPEG or DNG from PureRAW, it will not work.

Yeah it's probably just one pixel but LR renders it (when zoomed in to the pixel level) as 3 pixels, although the two surounding pixels are not necessarily white, but somtimes more of a light shade of blue or red or green so those could either be read errors from the sensors or pixels that are getting hot but haven't reached true "hot" status (ie. white pixel).

I'll have to play around with some of the other demoasicing methods and see what works. It's just something i started noticing, but going back to older images (from 1+ years ago) I now see them as well too, so I guess a bit of relief is that it's not anything new and it's happened on pretty much every camera I've owned, although I think the lower-res cameras like the Z5/Z6 were less prone to hot pixels, but they still did occur in some instances.

--
NOTE: If I don't reply to a direct comment in the forums, it's likely I unsubscribed from the thread/article..