Hackaday Prize 2022: Multispectral Smartphone Digicam Reveals Work’ Inside Secrets and techniques

Multispectral imaging, or images utilizing wavelengths apart from these in atypical seen mild, has varied functions starting from earth remark to forgery detection in artwork. For instance, titanium white and lead white, two pigments utilized in totally different historic eras, look equivalent in seen mild however have distinct signatures within the UV vary. Equally, IR imaging can reveal a portray’s interior layers if the pigments used are clear to IR.

Gear for such a distinct segment use is of course fairly dear, so [Sean Billups] determined to rework an older mannequin smartphone right into a handheld multispectral digital camera, which will help him analyze artistic endeavors with out breaking the financial institution. It makes use of the smartphone’s digital camera along with a filter wheel attachment that allows it to seize totally different spectral ranges. [Sean] selected to make use of a Google Pixel 3a, primarily as a result of it is cheaply accessible, but in addition as a result of it has a superb picture sensor and digital camera software program. Modifying the digital camera to allow IR and UV imaging turned out to be a little bit of a problem, nevertheless.

Picture sensors are naturally delicate to IR and UV, so cameras usually embrace a filter to dam something however seen mild. To take away this filter from the Pixel’s digital camera [Sean] needed to warmth the digital camera module to melt the adhesive, rigorously take away the lens, then glue a chunk of plastic to the filter and pull it out as soon as the glue had set. Perfecting this course of took a little bit of trial and error, however as soon as he managed to impact a transparent separation between digital camera and filter it was merely a matter of reattaching the lens, assembling the telephone and mounting the filter wheel on its again.

The 3D-printed filter wheel has slots for 4 totally different filters, which might allow quite a lot of IR, UV and polarized-light imaging modes. Within the video embedded beneath [Sean] reveals how the IR reflectography mode will help to disclose the underdrawing in an oil portray. The system is designed to be extendable, and [Sean] has already been including options like IR and UV LEDs, magnifying lenses and even further sensors like spectrometers.

We have seen a handful of multispectral imaging initiatives earlier than; this drone-mounted system was a contestant for the 2015 Hackaday Prize, whereas this venture comprises a wonderful primer on UV imaging.