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1. Click START and the SHIL Section Information screen will appear (Figure Fig. 18).
2. Scan the section barcode from the endcap
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Gamma: a digital camera setting that controls the grayscale reproduced on the image. An image gamma of unity (Fig. 3a-3b 19 missing) indicates that the camera sensor is precisely reproducing the object gray scale (linear response). A gamma setting much greater than unity results in a silhouetted image in black and white.
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- Color Standard values vary based on the standard and the manufacturer of the standard. Verify the values of the MacBeth Color Standard (multi color squares on the 3D standard, Fig ##. 20) before starting (How do we do this?). Check the grayscale card to determine what the percentage of gray. The target calibration values will vary based on the percentage of gray because the target values depend on the percent grayscale card. Max RGB value is 255. If using a 50% grayscale card, target red and green value is 127, a 25% grayscale card target value is 64, etc. For our QP 101 v4 card, the RGB values are 235, 111, and 80 (Fig. ##). All SHIL calibration standards are found in drawer PP-2B.
- Set camera f/stop to 22 (Fig. ## 22). F/22 is preferred preferred for standard scanning with the current light set up; F/16 is also acceptable. For hard rock cruises, where 360°whole 360° whole round scanning is required, a larger F/stop number is required.
- If you haven’t set the camera’s height, now is the time to do so! See the section Camera Height Adjustment at the end of the calibration section.
Figure ##20: 3D standard with MacBeth Color standard.
Figure ##: QP card 101 v4 grey scale standard.
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The following three steps in Calibration Check are designed for technicians to check the SHIL’s calibration and to determine if it needs to be adjusted. The calibration check is required to be done at the start of every expedition prior to receiving the first core. If adjustments to the calibration are needed, please see the Calibration section below.
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