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- These lights can get hot if the cooling fans are not used. The temperature is shown on the read out above the camera and is maintained at a temperature of 30 deg C°C. Imaging During a section will cause scan, the temperature to will range between 30 and 35 deg C°C. If Temperature goes about 50 deg C, above 50°C an alarm will sound. Notify a technician if that happensalarm sounds. Caution is needed when technicians perform the calibration process. Here, the lights are stationary and you must be conscious of the temperature of the lights. You can use the manual power switch to turn the lights on and off or the buttons in the software. Use the heat resistant grey silicone mat for the shading and pixel corrections. Do not use the plastic Gray card. Make sure the temperature is maintained between 30 and 35°C for calibration.
- 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 on the core surface, you can use our FLIR cameras to confirm that the temperature is ok.
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- Note which version of standard you are using. Each color standard values vary based on the version and the manufacturer of the standard. The X-Rite Colorchecker (MacBeth standard, Figure 20) 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). White On the MacBeth standard the RGB values of white is 243 and Black is 15 (Figure 21)black is 52. For the QP 101 v4 card, the RGB values are 235, 111, and 80 (Figure 21). All SHIL calibration standards are found in drawer PP-2B.
- Obtain the 3D standard (Figure 20), the gray silicone mat standardand the lens cap from PP-2B.
- Set camera f/stop to either F/16 or F/22 (Figure 22). The manufacturer suggested F/22 as the preferred for standard scanning with the current light set up however we have found F/16 work works well 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 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.
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Figure 20: 3D standard with Xrite Color checker (MacBeth Color) standard on the left.
Figure 21: QP card 101 v4 grey scale standard.
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Figure 22: Setting the F Stop on the Camera. Note that F/22 was recommended by the camera manufacturer but this is debated. F/16 is the preferred value by the imaging specialists onboard. Darker cores may need F/22.
Calibration Check
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.
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3. Click Rates and Exposure tab (Figure 24).
4. Check that the Max Image Scan Speed is equal to, or slightly more than the designated scan rate (Speed). The Max Image Scan Speed is usually between 8 to 10.
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Prepare the scan to assess the current image correction values. If you can achieve a good image by either adjusting, or better yet, keeping the same, values in the following steps , you will not need to adjust any of the camera settings in the JAI Camera Set-up window in the calibration instructions below (Calibration section).
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Here we check and can adjust our TIFF and JPEG Corrections. You may find you only need to slightly tweak the values and the calibration is good. However if the image appears streaky, a physical change has happened to the Camera or lights, the RGB values between corrected and expected are far off, or the graphs of either the tiff or jpeg don't look good, you will need to re-calibrate following the full calibration discussed below.
TIFF Correction Check
1. Click TIFF Correction Mode (Figure 29-2).
2. Click Uncorrected Image tab (Figure 29-3). This graph shows the measured red, green, and blue values of the gray scale color squares.
3. Click TIFF Correction tab to adjust the shape of the graph (Figure 29-4). The goal is to have line as straight as possible.
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1. Confirm the camera F-stop is set to F/16 or F/22 (Figure 31). F/22 is preferred by the cameral camera manufacturer for standard scanning with the current light set up however the imaging specialists onboard have been using F/16 and are confident F/16 works for our set up. For hard rock cruises, where 360° whole round scanning is required, a larger F-stop number is required (ie. F/22).
Figure 31: Setting the F Stop on the Camera.
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4. In Master Black field, enter 40. That is a good starting point. The last value used on the Master Black was 60, so you may want to try 60 now (Why?).
Color Balancing the Camera
Color Balancing should be done with the Xrite color checker MacBeth standard. The grey standard on the top of the track should be the QP card 101 v4 gray scale card. Be sure to use new color standards as some where damaged (faded) by the high temperature of the previous light set up. The MacBeth Method calibration using the MacBeth write standard card is described below (The note: the QP card v.4 101 method that was implemented in 2020 due to high temperature of lights is described at end of this User Guide if you need to reference that method).
Color Balancing Camera - MacBeth Color Checker Card
Make sure the lens is focused. Use the cm marks on the QP101 V4 card to focus the lens.
1. Put the Calibration Standard in the track (Figure 33). The color square must be oriented as pictured
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Figure 38.
Figure 3338: Color standard in track in correct orientation.
2. Select the tab RATES and EXPOSURE (Figure 3439).
Figure 3439: Rates and Exposure window, the tab is highlighted in red.
3. On the Green Lock control select OFF (Figure 3540). The other exposures are now adjustable.
Figure 3540: Green Lock control highlighted in red and set to off.
4. Set the Line Trigger Interval until the Max Image Scan Speed is 8 for nowabout 8 (between 8 and 10). Adjust values by clicking in the field and typing values. We’ll come back to this value later.
5. Turn on lights. Remember if the Temperature goes above 35 °C you must turn the lights off and wait until the temperature drops before proceeding.
6. Click the Start Grab (Figure 3641).
Figure 3641: Start Grab button highlighted in red.
7. Move the camera over the Macbeth color standard until you see the white, dark blue, orange and brown color bars in the image. Place the cursor in the white square, right-click and draw a rectangle by dragging diagonally. Release the mouse when you have select selected most of the white bar. The rectangle (marked in green) should only have the white color and nothing else inside (Figure 3742).
Figure 3742: The grab window is highlighted in red. A green square is drawn in the white color square of the appropriate row.
8. Above the image you will see controls values for the average RED, GREEN and BLUE values (RGB) for all of the pixels within the rectangle. You will also see the ratio values for RED/GREEN and BLUE/GREEN/BLUE.
9. Adjust the Red Exposure Interval value until the RED value is 245.
10. Adjust the Green Exposure Interval value until the RED/GREEN value is 1.
11. Adjust the Blue Exposure Interval value until the GREENBLUE/BLUE value GREEN value is 1. Congratulations you You just completed the White Balance of the upper limit of the camera, but you are not done.
12. Select the tab GAINS-BLACK-SHADE-FLAT and do the following:
13. Move the camera over the Macbeth color standard until you see the black, blue, gold and cyan color bars in the image. Place the cursor in the black square, right-click and draw a rectangle by dragging diagonally. Release the mouse when you have select most of the black bar.
14. Adjust the Master Black gain until the GREEN value is around 15.
15. Adjust the Red Black gain until the RED/GREEN value is 1.
16. Adjust the Blue Black gain until the GREEN/BLUE value is 1.
Adjust Gains
. Turn lights off by clicking Lights Off.
Adjust Gains
Master gain changes the whites/high RGB values. You can use positive or negative values. Master black changes blackMaster gain changes the whites/high RGB values. You can use positive or negative values. Master black changes black/low RGB values. You can only input positive values for Master Black. Without changing the gain values, the SHIL gives you a raw image with too high of a contrast. That is, whites are too bright, and blacks are too dark. You need to adjust the mid-tone and black level to achieve a good calibration. To do this, it is recommended to at least raise the master black. Lowering the master gain will help achieve a more ideal mid-tone, but be careful, because color can start to lose saturation when you do.
1.
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Select the
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tab GAINS-
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BLACK-
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SHADE-
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FLAT tab (Figure 39).
2.
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3. Click Lights ON. Preform the following steps as quickly as possible. Try to do it in 20 sec intervals with 60 sec lights off break.
4. Draw the green ROI box on the darkest square of th QP card 101.
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Turn Lights On by clicking Lights On. Remember if the Temperature goes above 35 °C you must turn the lights off and wait until the temperature drops before proceeding.
2. Move the camera over the Macbeth color standard until you see the black, blue, gold and cyan color bars in the image.
3. Place the cursor in the black square, right-click and draw a rectangle by dragging diagonally. Release the mouse when you have select most of the black bar.
3. Adjust the Master Black gain until the GREEN value is around 15 (Figure 43). Qualitatively, this is what's been found to produce a nice image. Please note that the RGB value of the black square is 52, but this will be corrected for that value in the TIFF/JPEG correction. Remember to turn off the lights regularly!
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4. Adjust the Red Black gain until the RED/GREEN value is 1.
5. Adjust the Blue Black gain until the BLUE/GREEN value is 1.
6. Keep an eye on the histogram graph on the bottom left corner (Figure 39). We want all the colors to overlay each other pretty closely. Adjusting the RedGain and BlueGain will move the colors (histographs) in the graph in the lower left, move until they are over lapping.
7. Adjusting the gain likely changed the RGB values in
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the White square of the MacBeth Color checker. Draw an ROI box in the
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White square. If the values aren't
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243 go back to the Rates and Exposure tab and adjust the the values until you hit
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243. Check back in the
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Black square and see its still
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about 15. Adjust until the Black reads 15 and White reads 243. This is a balancing act and can be
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tedious and remember to not let the temperature to go about 35 °C.
8 Click Lights Off
8. When the light grey (white) and the dark grey are well balanced you can move on to applying corrections. How long the lights have been will affect the color balance. If the lights have gotten quite warm and everything looks even, then when the lights are 'cold' the blue channel will be lower than the others.
9. Click Lights OFF
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Apply Corrections
We apply three corrections Pixel Black, Shading and Pixel Gain. Only do the corrections after you have finished adjusting the RGB exposure and Gain. Obtain the heat resistant silicone gray mat from the drawer PP-2B. The heat resistant silicon mat is also homogenous in color (no mottling as seen in the old grey cardboard card).
Pixel Black Auto Correction: The pixel Pixel Black Auto Correction: The pixel black level represents extra energy in the camera independent of a light source and is a consistent pattern in the sensor. To correct for this the light source must be turned off, the lens cap put on, and the camera internal correction circuit collects a few lines of data. An average is taken across the line, and pixels are either added to or subtracted from in order for each pixel to have the average value. (Vendor Manual Reference)
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Pixel Gain Correction - Flat Method: Each pixel has a different response to a fixed light source. To correct for this non-uniformity a couple lines of data are calculated (with the lights at no more than 80% of max) and the average response of the pixels are calculated. Then each pixel has a correction factor applied to bring all pixels to the average level. The Pixel Gain Correction also corrects for some shading effects and should be done after the shading correction (Note: the order of pixel gain and shading correction is debated, it is suggested to do it in the order above). If color streaking is evident in the image, this correction is needed to remove the unwanted streaking.
Pixel Black Auto Correction
1. Assure the lights are off
2. Take the lens cap (Figure 4044) and place on lens (Figure 4145). The lens cap is located in drawer PP-2B. The new light set up makes adding a lens difficult and it has been noted that added the lens may nat be needed if the lights are off but I have yet to test that.
Figure 40 44: Lens cap for the camera
Figure 41 45: Lens Cap being put on camera
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3. Click Pixel Black Auto Correction. The RGB lines in the Profile graph should be uniform (Figure 4246).
4. Remove lens cap when finished.
Figure 4246: Grab and Profile after the Pixel Black Correction applied.
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1. Take the heat resistant gray silicone mat and clean wooden board from the SHIL calibration drawer. Clean off any dust with a piece of tape (Figure 4347). Dust will cause unwanted artifacts in the image. The mat must be clean and flat on the track.
2. Place 2. Place the heat resistant gray silicone mat on the bench on top of the QP card 101, or anywhere along the bench, make track. Make sure that it is level and perpendicular to the camera’s axis.
3. Click Lights On, and move the camera over the gray mat.
4. This step is no longer needed (info with strikethrough formatting) because the silicone matting is homogenous. The previous material used had a mottle effect and thus defocusing was required to provide an even surface. If you find that defocusing is still valid please make a note. Defocus the lens on the camera just a little bit (Figure 44). Look at the Profile graph and slightly rotate the lens’ focus until the RGB lines are smoother, but still have some variation.
Figure 4347: The Gray silicone mat being cleaned with tape.
Figure 44: The lens being unfocused.
5. The RGB lines should appear “bowed” evenly across profile and centered in the image (Figure 4548). If not check the orientation of the gray mat, it needs to be flat and perpendicular to the camera. This very important!
Figure 4548: Grayscale card corresponding RGB Profile visible.
6. Click the Shading Correction - Flat Method button. This can take a few seconds, don’t click anything else until it is done. The RGB lines should now be flat (Figure 4649).
Figure 4649: Image grab and profile after the Shading Correction has been applied.
7. Click Lights OFF and wait , at least, 60 sec before proceedingfor temperature to decrease below 35 °C.
Pixel Gain Correction
1. The camera’s lens should still be de-focused. Make sure gray Make sure gray silicone mat is flat.
2. Click Lights ON
2. Click the Pixel Gain Correction - Flat Method button and move the camera very slowly back and forth. This averages the pixels and helps eliminate streaking in the image. This will take several seconds, don’t click anything else until it is done. When its done the RGB lines should still be flat and the individual RGB the same, but may not be equal to each other (Figure 4750).
Figure 4750: Grab and Profile after the Pixel Gain Correction has been applied.
3. Remove the gray mat. Move Camera over the mm increments on the standard and focus the lens by turning it manually.
4. Click Lights Off. (at At this point I wait 60 secs for lights to cool turn lights back on and check the light gray (white White square ) RGB values (243) again and adjust the exposure intervals if needed).
4. Click Save. The lights will turn off and the window closes.
5. In the IMS Control panel click Motion and then Drive Enable (Figure 4851). This allows the software to control the camera movement.
Figure 4851: Drive enable control highlighted.
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1. Place the 3D calibration standard on track as shown (Figure 4952). The color squares must be oriented as pictured below, butted against the red reflection bar.
Figure 4952: Color standard in track in correct orientation.
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3. Scan the STND Color barcod label (Figure 50b 53b). Check the ColorChecker Standard box (Figure 50a53a). With this box selected no corrections are applied to the image so we are able to assess the raw image quality.
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5. When the image has finished click Crop and then Save. We use the uncropped image so the crop here is not important.
Figure 5053: a) sample information screen with ColorChecker box checked, b) standard barcode being scanned.
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6. On the main IMS panel select Instruments and Camera: Image Correction (Figure 5154).
Figure 5154: Image Correction command selection.
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7. Select Open Test Image and select the image you just took (Figure 5255-1), located in C:/DATA/IN/IMAGE. It does not matter if the JPEG or TIFF file is loaded. The image loads into both the Original and Corrected windows.
8. Draw a ROI box loosely around the color checker in the Original box (Figure 5255-2)
9. Click Crop (Figure 5255-3).
10. Draw another ROI box around the Color Checker squares and this time making sure to only have MacBeth colorchecker in the box. White squares will appear inside each square. Adjust the box to get those white squares close to the center of the color squares. Do not click Crop again.
Figure 5255: Image Correction Window. Steps are indicated in the figure.
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1. Click TIFF Correction Mode (Figure 5356-2)
2. Click Uncorrected Image tab. This graph shows the measured red, green, and blue values of the gray scale color squares (Figure 5356-3).
3. Click TIFF Correction tab to adjust the shape of the graph. The goal is to have line as straight as possible (Figure 5356-4).
4. In the Tiff Correction tab adjust the LUT polynomial order values for the Red, Green, and Blue channels (Figure 5356-5). Adjust these values to create the lowest residual error with the smoothest curve in the Uncorrected Image tab. Values should be around 4. Make sure that the curve does not wave about. If it does the order values need to be lowered. Also check that the corrected ROI and MacBeth values should be very close. Make sure that the white does not exceed the MacBeth value. If you are unable to produce a reasonable correction curve, it is necessary to redo your White Balance by Shutter Correction in the Calibration section above.
Figure 5356: Steps for Tiff Correction illustrated on image. 1. Redraw box on color squares. 2. Select Tiff Correction Mode. 3. Put graph on Uncorrected Image. 4. Select Tiff Correction to view polynomial order. 5. Adjust polynomial order. 6. Check graph for linear relationship.
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1. Click JPEG Correction Mode (Figure 5457-1)
2. Click Applied Corrections tab (Figure 5457-2)
3. Click JPEG Corrections tab (Figure 5457-3). Adjust the Brightness, Contrast, and Gamma levels (Figure 5457-4) to achieve a straight line in the Applied Corrections tab and the ROI Corrected box should have values near 243 for the white square. We want a linear relationship between the measured and given values. Each BCG setting adjusts the line in different ways and there are many different ways to adjust the values to achieve a linear relationship. You want to achieve a good image with good brightness, where the image has good saturation and not too washed out. The Applied Corrections Graph should be a straight line and the ROI Corrected Box should have values near 250. These may change depending on the instance of extreme colors, extremely white or extremely dark cores, in which the settings may have be tweaked more to get a user friendly consumer image.
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2. Click the GRAB button and watch the image as you make slow camera position adjustments until the centimeter lines show up on the image graph as sharp spikes.
3. The graph as has two cursors, use the mouse and drag one cursor aligning it with the spike. Take the second cursor and do the same with an adjacent spike. Just above the Profile graph there is a control labelled Pixel Delta this value should be between 198 and 202 pixels. If not, adjust the camera (not lights up and down refocusing after every move until you get within the range. Warning this can be very tedious!
METHOD USED FOR HIGH TEMP LIGHTS Color Calibration with the QP 101 V.4 Card. Adjust Exposure (Achieving White Balance by Shutter Correction)
The aim of white balance is to correct the LED's lighting with the Red, Green and Blue sensor's sensitivity to produce neutral values for the QP101 V.4 standard. The exposure intervals we set relate to how long the camera can pick up values for each color band. Try not to keep the lights on for longer than ~ 20 sec and then keep them off for ~60 sec. As the lights warm up the RGB values change, particularly the blue value, and change most rapidly in the first minute of the lights warming up. Since the SHIL is often used after being off for a bit, we are trying to calibrate to represent the measuring conditions, as best we can. Right now we do not have a defined procedure for keeping the lights on/off during calibration and thus suggest 20 sec intervals.
1. Click the RATES and EXPOSURE tab (Figure 38-2).
2. On the Green Lock control select OFF (Figure 38-3). The RGB exposures are now adjustable.
3. Set the Line Trigger Interval until the Max Image Scan Speed is 8 to 10 (Figure 38-4). Imaging specialist suggests starting with 8.
4. Adjust values by clicking in the field and typing values or using the up and down arrow on the keyboard. The Line Trigger Value must be greater than the Exposure Intervals for red, green, and blue.
4. Move the camera carriage over the QP card 101 on the track.
5. Click Start Grab (Figure 38-5).
6. Click Lights ON (Figure 38-6). You should see the QP card 101 in the live grab window. Remember to only keep the lights on for ~20 sec and then turn off for ~60 sec while preforming the calibration.
7. Draw a green ROI box in the light gray (white) area. Now the Red, Green, and Blue values above the image grab window show the values inside your square. The RGB value of the QP card 101 v4 in the light gray (white) area is 235.
8. Adjust the Red, Green, and Blue Exposure times until each value in the live grab window is 235. Remember to turn off the lights regularly!
Figure 38: Rates and Exposure tab with chronological steps on the screen.
Color Balancing Camera - Old Method MacBeth Color Checker Card
1.Make sure the lens is focused. To focus the camera the lights need to be on and the camera over the section grayscale card or calibration card.
3. Put the Calibration Standard in the track (Figure 33). The color square must be oriented as pictured below.
Figure 33: Color standard in track in correct orientation.
4. Select the tab RATES and EXPOSURE (Figure 34).
Figure 34: Rates and Exposure window, the tab is highlighted in red.
5. On the Green Lock control select OFF (Figure 35). The other exposures are now adjustable.
Figure 35: Green Lock control highlighted in red and set to off.
6. Set the Line Trigger Interval until the Max Image Scan Speed is 8 for now. Adjust values by clicking in the field and typing values. We’ll come back to this value later.
7. Turn on lights.
8. Click the Start Grab (Figure 36).
Figure 36: Start Grab button highlighted in red.
9. Move the camera over the Macbeth color standard until you see the white, dark blue, orange and brown color bars in the image. Place the cursor in the white square, right-click and draw a rectangle by dragging diagonally. Release the mouse when you have select most of the white bar. The rectangle (marked in green) should only have the white color and nothing else inside (Figure 37).
Figure 37: The grab window is highlighted in red. A green square is drawn in the white color square of the appropriate row.
10. Above the image you will see controls for the average RED, GREEN and BLUE values for all of the pixels within the rectangle. You will also see the ratio values for RED/GREEN and GREEN/BLUE.
11. Adjust the Red Exposure value until the RED value is 245.
12. Adjust the Green Exposure value until the RED/GREEN value is 1.
13. Adjust the Blue Exposure value until the GREEN/BLUE value is 1. Congratulations you just White Balance the upper limit of the camera, but you are not done.
14. Select the tab GAINS-BLACK-SHADE-FLAT and do the following:
15. Move the camera over the Macbeth color standard until you see the black, blue, gold and cyan color bars in the image. Place the cursor in the black square, right-click and draw a rectangle by dragging diagonally. Release the mouse when you have select most of the black bar.
16. Adjust the Master Black gain until the GREEN value is around 15.
17. Adjust the Red Black gain until the RED/GREEN value is 1.
18. Adjust the Blue Black gain until the GREEN/BLUE value is 1.
Setting the Line Rate
The rules:
- Exposure intervals for the Red, Green and Blue channels is a function of the light intensity of the LEDs.
- Led intensity for the three channels is a function of the LED spectrum. Cold lights 65K are very blue while warm lights 55k are reddish. Neutral light is preferred where RGB are nearly equal but all leds are variable. Generally red is the lowest intensity and will require the longest exposure time. That is why in the above procedure we start with red, but you should always start with lowest intensity channel.
- Intensity is also a function of the F-stop. The smallest F-Top is preferred because it gives the greatest depth of focus but also lowers the intensity.
- Intensity is also a function of how closely coupled the lights are to the core surface but for practical reasons we need to keep a minimum clearance for safe operations.
- Don’t forget to check that all of the lights are evenly illuminated or even on. One led can fail without affecting these other. Don’t ever look at the leds directly!
- Line rate must be greater (20us) than the red, green and blue exposure rates set in the above procedure.
- The shorter the line rates the faster the image can be scanned.
- If you move the track faster than the scan rate you will see dropped lines in your image.
So you must balance all of these setting to obtain the best scanning rate. That means the above White balance procedure described above may have to be repeated as you adjust light position, f-stop etcetera.
Note: when you adjust the Line Rate interval it will automatically adjust the speed of the track to a scan speed that will not cause dropped lines. You can override this value in the Motion Control Setup …be careful.
1.Make sure the lens is focused. To focus the camera the lights need to be on and the camera over the section grayscale card or calibration card.
2. Put the Calibration Standard in the track (Figure 33). The color square must be oriented as pictured below.
Figure 33: Color standard in track in correct orientation.
3. Select the tab RATES and EXPOSURE (Figure 34).
Figure 34: Rates and Exposure window, the tab is highlighted in red.
4. On the Green Lock control select OFF (Figure 35). The other exposures are now adjustable.
Figure 35: Green Lock control highlighted in red and set to off.
5. Set the Line Trigger Interval until the Max Image Scan Speed is 8 for now. Adjust values by clicking in the field and typing values. We’ll come back to this value later.
6. Turn on lights.
7. Click the Start Grab (Figure 36).
Figure 36: Start Grab button highlighted in red.
8. Move the camera over the Macbeth color standard until you see the white, dark blue, orange and brown color bars in the image. Place the cursor in the white square, right-click and draw a rectangle by dragging diagonally. Release the mouse when you have select most of the white bar. The rectangle (marked in green) should only have the white color and nothing else inside (Figure 37).
Figure 37: The grab window is highlighted in red. A green square is drawn in the white color square of the appropriate row.
9. Above the image you will see controls for the average RED, GREEN and BLUE values for all of the pixels within the rectangle. You will also see the ratio values for RED/GREEN and GREEN/BLUE.
10. Adjust the Red Exposure value until the RED value is 245.
11. Adjust the Green Exposure value until the RED/GREEN value is 1.
12. Adjust the Blue Exposure value until the GREEN/BLUE value is 1. Congratulations you just White Balance the upper limit of the camera, but you are not done.
13. Select the tab GAINS-BLACK-SHADE-FLAT and do the following:
14. Move the camera over the Macbeth color standard until you see the black, blue, gold and cyan color bars in the image. Place the cursor in the black square, right-click and draw a rectangle by dragging diagonally. Release the mouse when you have select most of the black bar.
15. Adjust the Master Black gain until the GREEN value is around 15.
16. Adjust the Red Black gain until the RED/GREEN value is 1.
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Setting the Line Rate (From Older version of User Guide)
The rules:
- Exposure intervals for the Red, Green and Blue channels is a function of the light intensity of the LEDs.
- Led intensity for the three channels is a function of the LED spectrum. Cold lights 65K are very blue while warm lights 55k are reddish. Neutral light is preferred where RGB are nearly equal but all leds are variable. Generally red is the lowest intensity and will require the longest exposure time. That is why in the above procedure we start with red, but you should always start with lowest intensity channel.
- Intensity is also a function of the F-stop. The smallest F-Top is preferred because it gives the greatest depth of focus but also lowers the intensity.
- Intensity is also a function of how closely coupled the lights are to the core surface but for practical reasons we need to keep a minimum clearance for safe operations.
- Don’t forget to check that all of the lights are evenly illuminated or even on. One led can fail without affecting these other. Don’t ever look at the leds directly!
- Line rate must be greater (20us) than the red, green and blue exposure rates set in the above procedure.
- The shorter the line rates the faster the image can be scanned.
- If you move the track faster than the scan rate you will see dropped lines in your image.
LIMS Integration
Sample and Analysis Components
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