I have a question about technical implementation: how do you projecting patterns?
I mean - i saw TI DLP Lightcrafter EVM (+ DMD device) - it is pretty massive thing with big optics system, i saw analog projector with static line pattern on film - it is also pretty big.
So, i’m wodering - how it is possible to make 3d scanner in such small case.
It is structured Light projector . Patterns are usually generated by passing light through a digital spatial light modulator , typically based on one of the three currently most widespread digital projection technologies but if it is DLP, LC or LCOS I can’t tell you 10O%, however it is likely to be DLP .
DLP would also fits the best in this size scenario and the way it is working .
The pattern is not static and change from left to right constantly.
There is no image resolution as it does not project any image but moving fringe pattern , you have only 20cm at max between the scanner and the object to scan anything , so the captured area is very small .
How closer the object , how finer the fringe pattern and the minimum distance is 10cm.
If there was an image , they could have a bigger range for scanning as the image could be adjusted for different distances, but it is one static light pattern projection , how far you go how bigger the pattern , and how bigger the pattern how less accuracy you will get .
Yes it is phase shift fringe pattern, but the light source and the pattern are 2 separate things, I believe the pattern is on the micro mirror . Since the light source do not have any pattern and it’s direction is controlled by the micro mirror .
It do shifts 10 times per second as I made slow motion video to see what is happening from curiosity.
I don’t know yet exactly what kind of LED blue light it is , it behave as a black light but it is not , yellow surfaces absorbing it completely for that reasons any yellow surface are not visible by the scanner and literally glowing like under black light .
It also have issues with any color surface that has yellow in it like golden colors, brown warm reddish and green . However works fine with blue, magenta gray and white colors .
What make me thinking , how it going to scan colorful object with the RGB camera for texturing if it can’t see most of the basic colors , usually blue light scanners have also infrared light for support ,
Hi @npsg IR is best when it get about surfaces , as it can scan any colors including black cotton or velvet as long it is not synthetic .
It can scan any skin color , eye friendly , invisible and less destructive to delicate objects . It can scan well bigger objects .
It is not much affected by LED light , and in combination it can be used for capturing color textures at the same time as it don’t alter the original color , many blue light scanners using IR in combination to capture objects in full colors .
Blue light is more sensitive to LED but scan better with day light than IR, it can’t scan any colors that do not reflect blue light like yellow, brown, orange , red , green and any other color that is mixed or based with yellow.
It scans perfect white, gray, magenta, blue and most cool colors .
BL can’t scan dark skin , so dark brown and black skin can’t be scanned since it absorb blue light , you can’t scan black Cotton or black velvet , black or dark hair .
However BL is much more sharper so finer and smaller objects and details can be captured , it penetrates also much deeper the surface for better fine details scanning .
So if a good scanner is armed with both IR and BL you can get best results in any situation with any object .
For that reason MINI is not a replacement for POP2 as it can’t do what POP2 can do and vice versa, but it is simply a great companion.