Up and Coming
March 7, 2014
IMPORTANT - Improve Image Quality With IPD Adjusters
- 23 replies
- 20342 views
One of the biggest and most overlooked problems I have encountered with the developer kit is it's complete lack of Interpupillary distance (IPD) adjustments.
This has been mentioned a couple times in the past, however I have been blown away by the number of dev kit users who simply ignore or don't understand how big of a difference properly spaced lenses can make to improve picture quality, sharpness and clarity. If you know what your IPD is and it's within 62mm - 66mm respectively you should be close enough to the dev kits default 64mm value and realize only partial benefits from adjusters. However if your IPD is 61mm and below or 67mm or greater, or if you don't know what your actual IPD value is, it's important that you continue reading.
I cannot overstate how much of an improvement adjusters can make in the end. Depending on how high or low your IPD range is, I estimate adjusters provide a 15%-55% improvement in picture quality plus you get the comfort and convenience of having the sweet spot centered to your specific IPD which allows more room for shifting, movement and not having to re-adjust the dev kit every couple minutes. It's like having a custom tailored headset fitted to your exact measurements straight from a VR lab.
As we know, the developer kits suffer from larger pixel densities and lower resolution displays which results in a compromised final image. As such, it's essential other issues which may impede user vision be corrected as this is effectively the next step to improve image quality outside elements we have no control over.
When I first received my dev kit and started using it, one of the first things I realized was how frustrating it was for me to find and maintain that sweet spot necessary for a clearer picture. It's important to note that adjusting the dev kit up and down isn't a problem as anyone can simply adjust the head-strap accordingly for a proper vertical center. The real issue is once you try improving the picture by moving the lenses side to side.
In my experience, most people with IPD's outside the range of 61mm and 67mm don't realize they can improve picture quality in the side to side range substantially with the use of now available IPD adjusters specifically made for the dev kit's which can be found here: http://www.shapeways.com/shops/vrgear
Attached is a picture showing how the adjusters install and how they correct lens distance:
JCmIDMk.gif
The IPD adjusters allow the user to decrease or increase the lens separation to a level that is custom tailored to their specific IPD, thus correcting blurriness as a result of improper pupil to lens centers. The more your IPD is off from the default 64mm, the more blurry and worse the picture quality becomes. One of the easiest ways to test and determine if you have this problem is while wearing the dev kit simply close one eye and move it side to side until the image is as clear as possible, then without moving the dev kit switch to the other eye. If the other eye is blurry or you can't seem to center both eyes for the clearest image possible then your IPD is likely too far outside the range of the dev kits default values. During extensive testing I determined that anyone with IPD's outside of 61mm and lower or 67mm and higher should install IPD adjusters right away.
IPD Adjuster.jpg
As an optician who previously managed a vision clinic I encountered this problem frequently with day to day corrective eyewear in patients. Additionally, since my IPD is also outside the values outlined above (59.5mm) I too suffered from this problem as I couldn't seem to get both eyes centered as well.
I immediately set out to try and find a method to correct the problem, initially the only fix I could find involved a very questionable procedure involving foam, tape, hot gluing and even modding the lens cups which wasn't feasible in my mind. Many months after the release of the dev kit, a friend sent me a link to these: http://www.shapeways.com/designer/VR_Gear
I immediately ordered a pair. Inspected, installed and thoroughly tested them and was extremely satisfied with the results. I was initially concerned that installing them may correct my initial IPD issue but alter the picture as a result as IPD adjustments technically need to be altered on the software end as well to match the new lens center. I'm happy to report that the adjusters didn't make any notable change in picture quality at all. I fully confirmed this as I swapped between the original spacing and the new spacing many times to test my findings.
To find out what your IPD is, there are three easy methods to do this:
#1 - Use the Oculus calibration tool included in the SDK (retry the test a couple time to confirm your IPD)
#2 - Use a veneer caliper or similar measuring tool, while holding it in the mirror line up the center of each pupil (closing each eye) back and forth adjust the caliper to obtain your correct IPD. Then subtract half a mm (0.5mm) afterwards for convergence)
#3 - Go to a local eye doctor and ask them to take your IPD reading (they usually charge around $20 for this service)
It's important to note that simply ordering the IPD adjusters matched to your specific IPD isn't likely the best scenario in most cases since you want to try and divide your IPD difference between the software IPD (64mm) to try and balance out your visual improvement vs distortion. Even though I experienced no distortion in my case (I purchased the 62mm adjusters) it's important to note that everyone has a different IPD and depending how far you go from the default 64mm range, you may encounter picture distortion or loss of FOV. This is why I suggest balancing out these two aspects.
Below is a guide I designed after extensive testing which I found to offer the best results with IPD's 61mm and below:
(Due To Printer Tolerances, Finishing And Designer Revisions Use This Guide At Your Own Risk)
Users with an IPD of 59.5mm - 61mm should get the 62mm adjusters
Users with an IPD of 58.5mm - 59.4mm should get the 61mm adjusters
Users with an IPD of 58.4mm or lower should get the 60mm adjusters
Note: Depending on how far you turn the adjusters during installation, they offer about .75mm of play in each direction, for a total variation of 1.50mm back and forth. This excludes the 60mm adjusters because the lens cups physically touch each other in this case
Since I was only able to test for IPD values on the lower scale, users with IPD values 67mm and above can estimate what appropriate adjusters are required or they can contact the designer here: http://www.shapeways.com/forum/index.php?t=ppost&toi=408697&back_to_model=http://www.shapeways.com/model/1316565/60mm-lens-ipd-adjuster-oculus-rift-dk.html?li=send_message
One important aspect during installation is to ensure the eye area of the dev kit is clean and free of dust and hair prior to removing the lenses for adjuster installation. I strongly recommend running the OculusLCDScreenCleaner utility prior to removing the lenses to mark where the small dust spots are located on the screen. While you have the lenses removed use the included Oculus lens cleaning cloth to gently lift those specific particles off. You may have to repeat this procedure a couple times to remove all the black dust particles from the screen. Afterwards install the adjusters with "C" lenses on top of the adjusters in place of the "A" lenses.
Adjusters_Installed.jpg
Other important points worth mentioning. Any developers who normally use "C" or "B" lenses and intend to use the IPD adjusters as well must use contact lenses or their glasses afterwards to correct for nearsightedness as the shorter "C" lenses are required for use with the adjusters to obtain the same height the "A" lenses normally set at. Developers who intend to show off their dev kits should remove the adjusters as they will make the screen blurry for users with normal IPD's. Also, it's important to never use the Oculus calibration tool after the adjusters are installed as you will get incorrect results with them in place. This includes any other IPD calibration software including Valves TF2 calibration tool, so use those tools prior to installing the adjusters. Finally, combining the adjusters with an upscaled resolution from 1920x1200 or 1080p makes a huge improvement in picture quality over the native 1280x800. Try and run a minimum of 1080p at all times.
Anyone who installs these adjusters please post your results below for others to see and I wanted to give a big shout out to the designer of such an amazing product, these truly feel like an official Oculus accessory. Shapeways uses powder based 3D printers so the quality is superior to extruder based counterparts, thanks.
This has been mentioned a couple times in the past, however I have been blown away by the number of dev kit users who simply ignore or don't understand how big of a difference properly spaced lenses can make to improve picture quality, sharpness and clarity. If you know what your IPD is and it's within 62mm - 66mm respectively you should be close enough to the dev kits default 64mm value and realize only partial benefits from adjusters. However if your IPD is 61mm and below or 67mm or greater, or if you don't know what your actual IPD value is, it's important that you continue reading.
I cannot overstate how much of an improvement adjusters can make in the end. Depending on how high or low your IPD range is, I estimate adjusters provide a 15%-55% improvement in picture quality plus you get the comfort and convenience of having the sweet spot centered to your specific IPD which allows more room for shifting, movement and not having to re-adjust the dev kit every couple minutes. It's like having a custom tailored headset fitted to your exact measurements straight from a VR lab.
As we know, the developer kits suffer from larger pixel densities and lower resolution displays which results in a compromised final image. As such, it's essential other issues which may impede user vision be corrected as this is effectively the next step to improve image quality outside elements we have no control over.
When I first received my dev kit and started using it, one of the first things I realized was how frustrating it was for me to find and maintain that sweet spot necessary for a clearer picture. It's important to note that adjusting the dev kit up and down isn't a problem as anyone can simply adjust the head-strap accordingly for a proper vertical center. The real issue is once you try improving the picture by moving the lenses side to side.
In my experience, most people with IPD's outside the range of 61mm and 67mm don't realize they can improve picture quality in the side to side range substantially with the use of now available IPD adjusters specifically made for the dev kit's which can be found here: http://www.shapeways.com/shops/vrgear
Attached is a picture showing how the adjusters install and how they correct lens distance:
JCmIDMk.gif
The IPD adjusters allow the user to decrease or increase the lens separation to a level that is custom tailored to their specific IPD, thus correcting blurriness as a result of improper pupil to lens centers. The more your IPD is off from the default 64mm, the more blurry and worse the picture quality becomes. One of the easiest ways to test and determine if you have this problem is while wearing the dev kit simply close one eye and move it side to side until the image is as clear as possible, then without moving the dev kit switch to the other eye. If the other eye is blurry or you can't seem to center both eyes for the clearest image possible then your IPD is likely too far outside the range of the dev kits default values. During extensive testing I determined that anyone with IPD's outside of 61mm and lower or 67mm and higher should install IPD adjusters right away.
IPD Adjuster.jpg
As an optician who previously managed a vision clinic I encountered this problem frequently with day to day corrective eyewear in patients. Additionally, since my IPD is also outside the values outlined above (59.5mm) I too suffered from this problem as I couldn't seem to get both eyes centered as well.
I immediately set out to try and find a method to correct the problem, initially the only fix I could find involved a very questionable procedure involving foam, tape, hot gluing and even modding the lens cups which wasn't feasible in my mind. Many months after the release of the dev kit, a friend sent me a link to these: http://www.shapeways.com/designer/VR_Gear
I immediately ordered a pair. Inspected, installed and thoroughly tested them and was extremely satisfied with the results. I was initially concerned that installing them may correct my initial IPD issue but alter the picture as a result as IPD adjustments technically need to be altered on the software end as well to match the new lens center. I'm happy to report that the adjusters didn't make any notable change in picture quality at all. I fully confirmed this as I swapped between the original spacing and the new spacing many times to test my findings.
To find out what your IPD is, there are three easy methods to do this:
#1 - Use the Oculus calibration tool included in the SDK (retry the test a couple time to confirm your IPD)
#2 - Use a veneer caliper or similar measuring tool, while holding it in the mirror line up the center of each pupil (closing each eye) back and forth adjust the caliper to obtain your correct IPD. Then subtract half a mm (0.5mm) afterwards for convergence)
#3 - Go to a local eye doctor and ask them to take your IPD reading (they usually charge around $20 for this service)
It's important to note that simply ordering the IPD adjusters matched to your specific IPD isn't likely the best scenario in most cases since you want to try and divide your IPD difference between the software IPD (64mm) to try and balance out your visual improvement vs distortion. Even though I experienced no distortion in my case (I purchased the 62mm adjusters) it's important to note that everyone has a different IPD and depending how far you go from the default 64mm range, you may encounter picture distortion or loss of FOV. This is why I suggest balancing out these two aspects.
Below is a guide I designed after extensive testing which I found to offer the best results with IPD's 61mm and below:
(Due To Printer Tolerances, Finishing And Designer Revisions Use This Guide At Your Own Risk)
Users with an IPD of 59.5mm - 61mm should get the 62mm adjusters
Users with an IPD of 58.5mm - 59.4mm should get the 61mm adjusters
Users with an IPD of 58.4mm or lower should get the 60mm adjusters
Note: Depending on how far you turn the adjusters during installation, they offer about .75mm of play in each direction, for a total variation of 1.50mm back and forth. This excludes the 60mm adjusters because the lens cups physically touch each other in this case
Since I was only able to test for IPD values on the lower scale, users with IPD values 67mm and above can estimate what appropriate adjusters are required or they can contact the designer here: http://www.shapeways.com/forum/index.php?t=ppost&toi=408697&back_to_model=http://www.shapeways.com/model/1316565/60mm-lens-ipd-adjuster-oculus-rift-dk.html?li=send_message
One important aspect during installation is to ensure the eye area of the dev kit is clean and free of dust and hair prior to removing the lenses for adjuster installation. I strongly recommend running the OculusLCDScreenCleaner utility prior to removing the lenses to mark where the small dust spots are located on the screen. While you have the lenses removed use the included Oculus lens cleaning cloth to gently lift those specific particles off. You may have to repeat this procedure a couple times to remove all the black dust particles from the screen. Afterwards install the adjusters with "C" lenses on top of the adjusters in place of the "A" lenses.
Adjusters_Installed.jpg
Other important points worth mentioning. Any developers who normally use "C" or "B" lenses and intend to use the IPD adjusters as well must use contact lenses or their glasses afterwards to correct for nearsightedness as the shorter "C" lenses are required for use with the adjusters to obtain the same height the "A" lenses normally set at. Developers who intend to show off their dev kits should remove the adjusters as they will make the screen blurry for users with normal IPD's. Also, it's important to never use the Oculus calibration tool after the adjusters are installed as you will get incorrect results with them in place. This includes any other IPD calibration software including Valves TF2 calibration tool, so use those tools prior to installing the adjusters. Finally, combining the adjusters with an upscaled resolution from 1920x1200 or 1080p makes a huge improvement in picture quality over the native 1280x800. Try and run a minimum of 1080p at all times.
Anyone who installs these adjusters please post your results below for others to see and I wanted to give a big shout out to the designer of such an amazing product, these truly feel like an official Oculus accessory. Shapeways uses powder based 3D printers so the quality is superior to extruder based counterparts, thanks.