You’re always near, even when you’re far…in IR that is.

You’re always near, even when you’re far…in IR that is.

Cheap camera chops…

I found an article written hundreds of years ago about CMOS image sensors requiring near IR filters.  These filters are needed because of the sensing range of CMOS image sensors.  Without the filters, the image processing becomes unstable.  This is because the processing is centered around the human visual sensing range.  So, long story short, 99% of CMOS image sensors come with the filter.  That’s cool I thought, and I proceeded to remove it from my cheap $30 web cam.  Sure enough, things looked a whole lot different.  Being a bit more curious, I thought what if I filtered out the regular light and just let in the near IR.  So I did and things really looked interesting.  I took it into a dark room and pressed the TV remote to light the room up.  It was cheap and dirty, but I had my first introduction to near IR image sensing.

An old hack revisited…

I had purchased a few 808-16 cameras a few years ago to replace the 480p crap cameras I was using 2 years earlier.  I still had one that looks like a flashlight.  This one I bought from NitroPlanes, a retail outfit for remote control aircraft.  It was a 480p camera that saved videos to a microSD card inside the flashlight housing.  What the hell, I didn’t have any use for it any more so I decided to hack the near IR filter out of the CMOS assembly and install a RGB filter.  The RGB filter is actually a small cut piece of floppy disk, another technology I no longer used.  I wasn’t done yet.  I also removed the stock white LEDs from the header board and installed IR LEDs that I had laying around.  Bingo, a new trick for an old dog.

Always room for improvement…

My 808-16 cameras are starting to get replaced with my array of 1080p cameras.  I’ve always been impressed with the quality for cost factor of the 808-16 cameras.  I would still like to use them, but they will taking on a more auxiliary role.  Turns out some folks at UC Berkeley had applied the near IR hack to the 808-16 and the results look impressive.  The one thing that I noticed with my 480p near IR flashlight camera was it ran in 2 modes, passive and active.  Passive mode was it picking up the IR light generated by external sources.  Active mode was it detecting the light emitted by the IR LEDs on the flashlight.

Careful with that IR laser Eugene

Now with more high power LEDs and lasers available, image lighting with IR has never been better.  It has been used for years for high end work and the costs for the devices have only recently dropped.  As luck would have it, the green lasers come with an IR filter.  These are not toys!  The energy that these devices produce at close range can cause irreversible damage to eyes.  The NIST had published a report on this in great detail.  Removing the IR filter will remove the safety mechanism.  This light is undetectable by the human eye and it is too late once the damage is noticed.

Long range illumination with near IR lasers is old hat for a few select folks.  It is an effective way to light a scene at night that is far away.  This video demonstrates one system that is professional grade.

Reminds me of the rental house in Maui.  Boy, I’m glad I can’t see in near IR, that would’ve been annoying to see.  The manufacturer (Cohu HD CoStar) of these systems also have an OEM product line.  The 1100 Series looks promising, but I don’t think it will fit well on my helmet.

Silly rabbit, tricks are for kids…

The traffic signal preemptive  system should not to be messed with.  It is against the law in most places and will most likely become illegal everywhere.  The TSPS is a control system that will change traffic signals for first responders to emergencies.  This is noble.  If I needed help, I would want it as fast as possible.  Give em the green light!  Not all systems are the same, but there are some that use near IR.  It’s not the same as your remote control, but the same principle.

Speaking of remote controls, there are some of us that love a good prank.  This has been around awhile and still resurrects.   The long range TV remote kit was made available from Adafruit and it is effective.  This high power flashlight version looks like it means business.  It could really cause a scene at the local sport bar by shutting off all the TVs at a critical moment.  I don’t condone or recommend the use of any of these systems in a manner that erodes the fabric of society.  If you can’t make adult choices, someone else should make them for you.


Comments are closed.