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Polarization Filter?
- Thread starter Ninanoki
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gedstar
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dv8_fx
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I found it..... but ooooops.... also found out you posted it and was entirely different as it touched on "tooth color analysis" .....
.thebestcpu
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Hi Ninanoki
It is apparent that the product information you shared uses both polarized light and a polarized filter to eliminate reflections and differentiate dentin and enamel. I am assuming that you want a similar result without using that product and also without using your own polarized lights and polarized filters (correct me if I am wrong).
If my assumptions are correct, just to be clear, one cannot duplicate the polarized light effect in PS with standard lighting. The almost exact parallel to is to try and differentiate color in a B&W image. The polarization information in light is not captured in a standard image and therefore is not there to be adjusted/manipulated to ones advantage.
So I will assume that you want the ability to better differentiate colors in a standard image. If there is a hue or saturation difference between the dentin and enamel in a standard image then there might be a way to amplify that difference into a luminosity difference and give you something of interest. To have good differentiation though, from my experience it will be very important to have either a raw image or a 16 bit TIFF image to start from to see what can be done. This is because the hue and saturation differences are subtle and unfortunately, JPEG images compress the hue and saturation (actually posterizes those components) and the 8 bit depth make differentiation of small differences very hard or impossible.
If you could provide a high resolution raw image or 16 TIFF image of some example teeth then I think forum members could give it a real good shot to see what could be done. That would be my first suggestion.
It is apparent that the product information you shared uses both polarized light and a polarized filter to eliminate reflections and differentiate dentin and enamel. I am assuming that you want a similar result without using that product and also without using your own polarized lights and polarized filters (correct me if I am wrong).
If my assumptions are correct, just to be clear, one cannot duplicate the polarized light effect in PS with standard lighting. The almost exact parallel to is to try and differentiate color in a B&W image. The polarization information in light is not captured in a standard image and therefore is not there to be adjusted/manipulated to ones advantage.
So I will assume that you want the ability to better differentiate colors in a standard image. If there is a hue or saturation difference between the dentin and enamel in a standard image then there might be a way to amplify that difference into a luminosity difference and give you something of interest. To have good differentiation though, from my experience it will be very important to have either a raw image or a 16 bit TIFF image to start from to see what can be done. This is because the hue and saturation differences are subtle and unfortunately, JPEG images compress the hue and saturation (actually posterizes those components) and the 8 bit depth make differentiation of small differences very hard or impossible.
If you could provide a high resolution raw image or 16 TIFF image of some example teeth then I think forum members could give it a real good shot to see what could be done. That would be my first suggestion.
here is a high quality tooth image.http://pawellabno.pl/tooth.nef
thebestcpu
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Hi Ninanoki
Here is what can be done with your raw image.
All I did was bring it into PS in 16 bit and ProPhoto RGB
Convert to Lab mode
Then added a 50% gray level Layer above the original and set blend to Luminosity (this is to isolate the colors)
Then added a curves adjustment Layer and use the Auto function only on the "a" and "b" channels
Then added a posterization adjustment Layer and in this case set the levels to 5
This should give you a hue/sat colorized map of your image that is posterized to visually show you the different areas
Something similar can be done for luminosity by itself.
Now, this is not calibrated to anything so I am sure a lot more is involved. Is this anything along the lines of which you seek?
John Wheeler
Use a curves adjustment Layer and used the auto button on the a and b channels
Here is what can be done with your raw image.
All I did was bring it into PS in 16 bit and ProPhoto RGB
Convert to Lab mode
Then added a 50% gray level Layer above the original and set blend to Luminosity (this is to isolate the colors)
Then added a curves adjustment Layer and use the Auto function only on the "a" and "b" channels
Then added a posterization adjustment Layer and in this case set the levels to 5
This should give you a hue/sat colorized map of your image that is posterized to visually show you the different areas
Something similar can be done for luminosity by itself.
Now, this is not calibrated to anything so I am sure a lot more is involved. Is this anything along the lines of which you seek?
John Wheeler
Use a curves adjustment Layer and used the auto button on the a and b channels
thanks John, it works, I was able to create such action and got the same result but how do you make a 50 % gray layer?
i also wonder which method is better. i can also trace an image in adobe illustrator and depending on number of colors i get such results:
i also wonder which method is better. i can also trace an image in adobe illustrator and depending on number of colors i get such results:
thebestcpu
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Hi Ninanoki
You make a 50% gray level by first creating a blank Layer and then using Edit > Fill > 50% Gray with normal blend and 100% opacity options
To be honest, what you have created does not look similar to my image. Yet I am glad you feel you are on your way to something you need.
For your reference, here is a link to the Layered TIFF file for the image I created so you can see the details of the process I used: https://www.dropbox.com/s/00rloc18hk2araa/tooth copy.tif?dl=0
Hope that is of some help.
John Wheeler
You make a 50% gray level by first creating a blank Layer and then using Edit > Fill > 50% Gray with normal blend and 100% opacity options
To be honest, what you have created does not look similar to my image. Yet I am glad you feel you are on your way to something you need.
For your reference, here is a link to the Layered TIFF file for the image I created so you can see the details of the process I used: https://www.dropbox.com/s/00rloc18hk2araa/tooth copy.tif?dl=0
Hope that is of some help.
John Wheeler
thebestcpu
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I am no expert on polarized light or appropriate filters. However, the basics are that if you have some elements of light that are polarized (such as possible from reflections), you can adjust the filter to reduce/eliminate that particular reflection. Light from most sources is not polarized yet can become polarized through a variety of process (reflection is just one).
Sometimes it is just experimentation on how the filter is adjusted. Here is a link that will explain the basics: http://www.physicsclassroom.com/class/light/Lesson-1/Polarization