{"id":1128,"date":"2014-07-07T04:31:26","date_gmt":"2014-07-07T04:31:26","guid":{"rendered":"http:\/\/192.168.3.4\/?p=1128"},"modified":"2018-01-09T06:49:37","modified_gmt":"2018-01-09T14:49:37","slug":"youre-always-near-even-when-youre-far-in-ir-that-is","status":"publish","type":"post","link":"https:\/\/www.cloudacm.com\/?p=1128","title":{"rendered":"You’re always near, even when you’re far…in IR that is."},"content":{"rendered":"

Cheap camera chops…<\/strong><\/p>\n

I found an article written hundreds of years ago about CMOS image sensors requiring near IR filters.\u00a0 These filters are needed because of the sensing range of CMOS image sensors.\u00a0 Without the filters, the image processing becomes unstable.\u00a0 This is because the processing is centered around the human visual sensing range.\u00a0 So, long story short, 99% of CMOS image sensors come with the filter.\u00a0 That’s cool I thought, and I proceeded to remove it from my cheap $30 web cam.\u00a0 Sure enough, things looked a whole lot different.\u00a0 Being a bit more curious, I thought what if I filtered out the regular light and just let in the near IR.\u00a0 So I did and things really looked interesting.\u00a0 I took it into a dark room and pressed the TV remote to light the room up.\u00a0 It was cheap and dirty, but I had my first introduction to near IR image sensing.<\/p>\n

An old hack revisited…<\/strong><\/p>\n

I had purchased a few 808-16 cameras a few years ago to replace the 480p crap cameras I was using 2 years earlier.\u00a0 I still had one that looks like a flashlight.\u00a0 This one I bought from NitroPlanes<\/a>, a retail outfit for remote control aircraft.\u00a0 It was a 480p camera that saved videos to a microSD card inside the flashlight housing.\u00a0 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.\u00a0 The RGB filter is actually a small cut piece of floppy disk<\/a>, another technology I no longer used.\u00a0 I wasn’t done yet.\u00a0 I also removed the stock white LEDs from the header board and installed IR LEDs that I had laying around.\u00a0 Bingo, a new trick for an old dog.<\/p>\n

Always room for improvement…<\/strong><\/p>\n

My 808-16 cameras are starting to get replaced with my array of 1080p cameras.\u00a0 I’ve always been impressed with the quality for cost factor of the 808-16 cameras.\u00a0 I would still like to use them, but they will taking on a more auxiliary role.\u00a0 Turns out some folks at UC Berkeley<\/a> had applied the near IR hack to the 808-16 and the results look impressive.\u00a0 The one thing that I noticed with my 480p near IR flashlight camera was it ran in 2 modes, passive and active.\u00a0 Passive mode was it picking up the IR light generated by external sources.\u00a0 Active mode was it detecting the light emitted by the IR LEDs on the flashlight.<\/p>\n

Careful with that IR laser Eugene<\/strong><\/a>…<\/strong><\/p>\n

Now with more high power LEDs<\/a> and lasers<\/a> available, image lighting with IR has never been better.\u00a0 It has been used for years for high end work and the costs for the devices<\/a> have only recently dropped.\u00a0 As luck would have it, the green lasers come with an IR filter.\u00a0 These are not toys!\u00a0 The energy that these devices produce at close range can cause irreversible damage to eyes.\u00a0 The NIST had published a report <\/a>on this in great detail.\u00a0 Removing the IR filter will remove the safety mechanism.\u00a0 This light is undetectable by the human eye and it is too late once the damage is noticed.<\/p>\n

Long range illumination with near IR lasers is old hat for a few select folks.\u00a0 It is an effective way to light a scene at night that is far away.\u00a0 This video demonstrates one system that is professional grade.
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