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When setting up the JAI camera we are not moving and not receiving trigger pulses. In this mode we use the line rate trigger (free run) to simulate the encoder trigger period.
Before Starting:
- Note which version of standard you are using. Each color standard values vary based on the version and the manufacturer of the standard. The XRite Colorchecker 2019 (MacBeth standard, Figure 5) is the preferred card to use for calibration. The program is set up to use the White and Black squares on the XRite Colorchecker (MacBeth standard). On the Xrite color checker standard the RGB values of White and Black are listed here for various illuminants. White RGBs are 242, 242 and 236 and and black RGBs are 49, 49, 50 (those values are calculated using illuminant D65), as of there is discussion that we will use RGBs calculated under illuminant A as it better matches our LED lights. Using illuminant A the RGBs for white is 240, 242, 235 and black is 50, 50, 50. For the QP 101 v4 card, the RGB values are 235, 235, 235 (light grey), 111, 111, 111 (medium grey), and 80, 80, 80 (dark grey) (Figure 6). All SHIL calibration standards are found in drawer PP-2B.
- Obtain the 3D standard (Figure 5) and the gray silicone mat standard from PP-2B.
- Set camera f/stop to either F/16 or F/22 (Figure 7). The camera manufacturer suggested F/22 as the preferred f/stop for scanning with the our light set up however we have found F/16 works well for our section halves and is the most used f/stop for calibration and scanning sections. For hard rock cruises, where 360° whole round scanning is required, a larger f/stop number maybe 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. The camera height should not need to change between expeditions.
Figure 5. 3D standard with Xrite Color checker (MacBeth Color) standard on the left.
Figure 6. QP card 101 v4 grey scale standard.
Figure 7. Setting the f/stop on the Camera. F/16 is the preferred value by the imaging specialists onboard. Darker cores may need a larger f/stop of F/22.
a) Calibration Check using Image Correction
The following calibration check is designed for technicians to check the SHIL’s calibration. 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.
Determine the Scan Rate for the Expedition
Talk to your science party to determine what scanning parameters (scan rate) they wish to use. A typically scan rate has been between 8-10 cm per second. Note, with the new, brighter LED lighting system, faster scan rates can be achieved compared to expeditions prior to Expedition 390C.
1. Launch IMS on the SHIL computer
2. Click on DAQ and click Image Capture Motion Setup
3. Compare the current scan rate (Speed) to the requested rate. The Speed (Figure 8) of the camera will be in the first box. If the values need to be changed to match the requested values by the science party, please proceed to the calibration section below as you will need to do a full calibration. If the values match, close the ‘Image Scan Setup’ window and proceed with the following checks. Speed of 8 to 10 is the most common values and the speed must be less than the scan speed value calculated in the JAI Camera Setup utility (see info below). Note that the speed rarely changes between expeditions.
Figure 8. Checking the Image Scan Speed.
Check the Line Trigger Interval rate
The Line Trigger Interval dictates the Max Image Scan Speed.
1. Click on Instruments and open the JAI Camera Set-up window.
2. Turn the lights off IMMEDIATELY by clicking Lights OFF. Remember the lights produce a lot of heat and we want to maintain the calibration at temperatures between 30-39 °C.
3. Click Rates and Exposure tab (Figure 9).
4. Check that the Max Image Scan Speed is equal to, or slightly more than the designated scan rate (Speed, Figure 8). The Max Image Scan Speed is usually between 8 to 10.
When you adjust the Line Trigger Interval you will notice that the Max Image Scan Speed value changes. If you scan faster than this, you dropped lines but you can scan slower with affecting the calibration. When you click Save in this Utility the value in the Image Scan Setup window will be updated but you are allowed to change this value but should always be lower not higher. As a general rule we want to stay at 8-cm/s or higher to maintain core flow in the lab.
After you done a few calibrations you will develop a feel for what is possible with current set up but if you just stating we recommend setting the line rate to emulate a scan speed of 8-cm/s.
Now you are ready to start setting the exposures for the RGB channels.
- Turn on the lights
- Click the START GRAB button
- Move the camera over the white square on the ColoChecker standard.
- Use the mouse and draw a ROI (Region of Interest) square with only the white square inside. The RGB values and Ratio values will only be calculated for the pixels inside the ROI.
- Go to the Gains-Black-Shades-Flat tab and click the Clear All Gains and click Clear Black Gains
- Go to the Rates and Exposure tab and set the Green Lock to Off
At this point look at the intensity graph
Before Starting:
- Note which version of standard you are using. Each color standard values vary based on the version and the manufacturer of the standard. The XRite Colorchecker 2019 (MacBeth standard, Figure 5) is the preferred card to use for calibration. The program is set up to use the White and Black squares on the XRite Colorchecker (MacBeth standard). On the Xrite color checker standard the RGB values of White and Black are listed here for various illuminants. White RGBs are 242, 242 and 236 and and black RGBs are 49, 49, 50 (those values are calculated using illuminant D65), as of there is discussion that we will use RGBs calculated under illuminant A as it better matches our LED lights. Using illuminant A the RGBs for white is 240, 242, 235 and black is 50, 50, 50. For the QP 101 v4 card, the RGB values are 235, 235, 235 (light grey), 111, 111, 111 (medium grey), and 80, 80, 80 (dark grey) (Figure 6). All SHIL calibration standards are found in drawer PP-2B.
- Obtain the 3D standard (Figure 5) and the gray silicone mat standard from PP-2B.
- Set camera f/stop to either F/16 or F/22 (Figure 7). The camera manufacturer suggested F/22 as the preferred f/stop for scanning with the our light set up however we have found F/16 works well for our section halves and is the most used f/stop for calibration and scanning sections. For hard rock cruises, where 360° whole round scanning is required, a larger f/stop number maybe 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. The camera height should not need to change between expeditions.
Figure 5. 3D standard with Xrite Color checker (MacBeth Color) standard on the left.
Figure 6. QP card 101 v4 grey scale standard.
Figure 7. Setting the f/stop on the Camera. F/16 is the preferred value by the imaging specialists onboard. Darker cores may need a larger f/stop of F/22.
a) Calibration Check using Image Correction
The following calibration check is designed for technicians to check the SHIL’s calibration. 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 below5. Again, if the values need to be changed to match the requested values by the science party, please proceed to the calibration section below. If the values match, close the JAI Camera Set-up window and proceed.
Figure 9. Checking the Max Image Scan Speed.
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