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# facial recognition at 150 meters

#### bickford

##### Getting comfortable
Hello all

I am looking for a bullet camera to recognize face at 150 meters ...

Can the Dahua Z12 do the job for this or i need more optical zoom ?

Thanks

BICK

#### bigredfish

##### Known around here
My Z12's are zoomed in about 120ft which appears to be about 80%+ for LPR. I dont see being able to ID faces at almost 500ft no way.

#### bickford

##### Getting comfortable
Done tests with IPVM ...

BICK

#### bigredfish

##### Known around here
Perhaps Im doing something wrong?

#### bp2008

Staff member
That looks correct, more or less. You each picked slightly different models in the calculator, and metric vs imperial units.

The Sentinel Black facial recognition software wants a face to be at least 100 pixels so 38 pixels per foot is very much lacking. I think even a 25x PTZ would not be sufficient. Maybe like 45x...

#### mat200

IPCT Contributor
At 19.2 feet across = FOV for 100 ppf for a 2MP / 1080P camera.

150 meters = 495 feet... rounding up to 500

cheating on the math a bit - can do due to the 500 feet distance w/o too much error we can cheat on this and skip the arc calculations.

sin A/2 = ( 19.2/2 ) / 500 feet = .0192 degrees - or FOV is 2x that so 0.038 degrees

You would need a 2MP camera able to do a very narrow FOV at that range - 0.038 degrees

#### bickford

##### Getting comfortable
Perhaps its better to go to a PTZ camera ...

BICK

BICK

#### mat200

IPCT Contributor
FYI - Dahua uses less than 100 ppf for their I DORI calculations ( that is the ID in the DORI )

#### bigredfish

##### Known around here
Tell ya what, I'll try and setup a test this week with one of mine at 500ft

#### bigredfish

##### Known around here
See image below. This shows the view from the Dahua 8231 showing the culdesac and the 110 ft mark I use for tag capture with the 5231-Z12

This shows distances (in feet) I measured off today. This image is from the 8231 that sits beside the Z12 on the same pole/same height.

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#### bickford

##### Getting comfortable
Very nice thanks !
waiting for the Z12
BICK

#### bigredfish

##### Known around here
Here for reference is the Z12 at 80% zoom as I have it to capture tags at that 110ft mark

#### bigredfish

##### Known around here
Due to the angle the Z12 is mounted on the pole, I couldnt zoom to the 500ft mark (150meters) but you see clearly at 309ft, there is no way you can use this cam for ID at those distances. This image is at the same 80% zoom

#### bigredfish

##### Known around here
And here it is at 100% zoom pointing at me at 309ft. It would not focus at 100% zoom in color or B&W. Serious flaw with this camera.

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#### bickford

##### Getting comfortable
thanks for this work !

BICK

#### bigredfish

##### Known around here
Here is the video clip of me trying to get it to focus at 100% zoom at 309ft. Nothing I could do would get it to focus at 100% zoom.

Only when I switched back to B&W and used "Auto Focus" a couple of times did it finally focus back at 80% zoom. Seems that anything beyond 80% zoom and this camera doesnt want to focus. Ive seen others on the forum with the same problem.

(remember to switch youtube player to 1080p)