Camera Assembly

Equipment:

• Socket head Allen key

Materials:

• Lucid Vision Labs TRI054S-CC Sensor
• Custom Camera Mounting Base, 1" x 3" x 3/8”
• 18-8 Stainless Steel Socket Head Screws, Black Oxide, M2 x 0.40 mm Thread, 8 mm Long
• Loctite Threadlocker

Steps:

• Apply threadlocker to each 18-8 socket head screw before criss-cross tightening in place to attach base to camera

  

  

Lens, lens tube and bubble level assembly

Equipment:

• Scissors/box cutter
• Cotton tipped applicator

Materials:

• Bubble level
• Double sided sticky tape
• Fujinon C-Mount 5MP 2/3″ 6mm OR 16 mm lens
• IP67 C-Mount Lens Tube, Inner ⌀: 59mm, Inner Length: 55.5mm OR IP67 C-Mount Lens Tube, Inner ⌀: 35.5mm, Inner Length: 59.9mm
• DOWSIL™ 3145 RTV Mil-A-46146 Adhesive / Sealant

Steps:

• Lens and lens tube are picked based on the customer’s FoV requirements

• Attach and tighten lens tube base to camera until it is flush with camera body. This is important otherwise lens will not screw in securely to the camera body.

• Attach specified lens to camera body, tighten until secure.

• Attach lens cover to lens tube base. Do not tighten completely, focus might need readjusted later.

• Center and attach bubble level to the top of the camera body using thin double sided stick tape

  

Aperture and Focus

• Each lens has two knobs that control aperture and focus respectively
• Set aperture to fully open (lowest f/stop). Hand tighten knob, then use pliers to tighten for another turn or so. Do not over-tighten or the screw might break.
• Point camera out the window at a small/sharp object (like antenna on building or power lines) at a large distance (>100 meters). Adjust the focus knob while viewing the camera output on ArenaView application to get the chosen object as sharp as possible in the image. Hand tighten knob, then use pliers to tighten for another turn or so. Do not over-tighten or the screw might break. Verify while using Geocal.

Calibrating Intrinsics using Geocal

• Connect cameras and Windows host to ethernet switch to access camera stream/update firmware.
• New calibration parameters should be uploaded to Github following the common format: https://github.com/nodarsensor/camera_intrinsics

• Setup cameras on the tripod in front on the Geocal. Position as close as possible without touching the glass. The principal axis of the lens should be aligned perpendicular to the Diffractive Optical Element. A relative rotation of +/- 2 degrees is allowed.
• For more details on using Geocal, refer to the user manual and check out our notion page on Geocal Calibration Tips.

• Navigate to ArenaView and connect to the camera.

  • Set PixelFormat to Mono8

  • Set Exposure Auto to Off

  • Set Gain Auto to Off

  • Set Gain to 0.0dB

  • For 16mm lenses

    • Set Exposure to 100us

      

  • For 6mm lenses

    • Set Exposure to 10000us

      

  • The exposure value above is a trade-off between the size of individual points in the pattern (which we want to minimize by lowering exposure) and total number of points visible/detectable in the image (which we want to maximize).

  • Make sure the point grid covers the whole image

• Check focus

  • Zoom into to a point that is not the 0th diffraction order (brightest spot in the center of the grid). See if the point is sharp.

  • Example of bad focus:

    

  • Example of good focus

    

• Check alignment between the camera and Geocal

  • Good alignment

    

  • Bad alignment

    

• Save a non-compressed PNG/TIFF image using ArenaView.

• Load image in Geocal Software. Detect and Analyse to obtain intrinsic parameters. Ensure Reprojection RMSE is within acceptable bounds for the lens-camera combination.

  • ~0.35 pixels for 16mm lenses
  • ~0.5 pixels for 6mm lenses

• Save Geocal instrinsics as CSV and upload here in camera serial indexed folder.

• Apply DOWSIL 3145 RTV Adhesive with a cotton-tipped applicator on:

  • Aperture knob
  • Focus knob
  • Joint between camera and lens