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Maintenance
Instrument Preparation
Preparing the SHIL for imaging cores requires adjusting the light system height and calibrating the camera (applying corrections). The position of the lights once set should be stable through out the expedition unless changes are needed for variations in core height (hard rock versus sediment versus 360 imaging). The technical staff will calibrate the camera settings when ever the light source is moved or unwanted artifacts are present in the images.
Setting up the Lights (Section for old lighting system, delete when new lighting system is approved)
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The laboratory technician calibrates the system when needed by adjusting camera settings and analyzing an imaged QP 101 V4 Color Standard. The current light system obtains nearly uniform illumination intensity from the core’s surface (half or whole round) to the bottom of the liner by a combination of high intensity, overlapping large diameter light source, close coupling to the imaged surface and the “line” image plane. The bottom edge of the brass led mount should be set between 2 and 4-cm 4cm from the image surface. For uneven hard rock cores the height can be set higher but illumination intensity will drop, exposure times lengthen, f-stop opened and scanning speed reduced. Note, any height change to the lights requires re-calibration. Heat is removed from the LEDSs LEDs and transferred to the surrounding air via the copper heat pipes. While these to get hot they are not a burn hazard. However they are very delicate and bend at the slightest touch, so use care when working with the camera lens.
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For more detailed information on the theory behind the calibration please refer to the Advanced SHIL Calibration page.
Safety Concerns
- These lights get hot and can damage or burn surfaces if left stationary and on for over 20-secs. This is not an issue during normal imaging operations and will not heat the core surface at all. BUT during calibration process when the lights are stationary you must use the manual power switch to turn the lights on and off. Do not use the plastic Gray card but use the cardboard instead.
- Never look at the leds directly! Even the reflected light can be painful! When working under the track make sure that the power is off.
- NOTE: if you are concerned with the heat dissipation, you can use our FLIR cameras to confirm that everything is ok.
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