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- These lights get hot and can damage or burn surfaces if left stationary and on for over 20secs. This is not an issue during normal imaging operations and will not heat the core surface at all. Bus during calibration process when the lights are stationary you must be aware of the length of time the lights are on. 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. (testing needs to be completed on which color silicone mat is best to use, or if color difference matters)
- 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 the temperature is ok.
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- Click on Instruments and open the JAI Camera Set-up window.
- Turn the lights off IMMEDIATLY IMMEDIATELY by clicking Lights OFF (Fig. ##). Remember the lights produce a lot of heat and can cause damage to anything underneath them if they remain stationary for too long.
- Click Rates and Exposure tab (Fig. ##)
- Check that the Max Image Scan Speed is equal to, or slightly less than the designated Scan Rate.
- 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.
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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. For more detail on the graphs and values in the Image Correction window please see Create Correction Curve section below.
TIFF Correction Check (Fig. ##)
1. Click TIFF Correction Mode
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The main Image Correction window displays three main areas:
A. Graph panel: Main graphical viewing area on the left side of the screen.
Uncorrected Tab: 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. The goal is to have line as straight as possible.
Applied Corrections Tab: Applies polynomial fit corrections to the RGB lines.
B. Image Viewing Panels: Area in upper right portion of the screen that displays the original and corrected test image and color checker with RGB values.
Original: Displays the uploaded tiff.
Corrected: Displays the uploaded tiff with corrections applied.
Color Checker: Displays the known values of the MacBeth Color Checker values
C. Correction Panel: Panel in the lower right portion of the screen that allows user to apply corrections to the image
TIFF Correction: Shows tiff red, green, and blue polynomial fit.
JPEG Correction: Shows brightness, contrast, and gamma settings.
Instructions: Shows instructions to follow in this window.
TIFF Correction Check (Fig. ##)
1. Click TIFF Correction Mode
2. Click Uncorrected Image tab. 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. The goal is to have line as straight as possible.
4. Adjust the Red4. Adjust the Red, Green, and Blue polynomial orders to create the lowest residual error with the smoothest curve in the Uncorrected Image tab. Values should be around 3 or 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 correction in the Calibration section below. (see TIFF corrections cheat sheet in SHIL lab notebook, to be added).
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Color Balancing is currently being done using the QP card 101 v4 gray scale card. The MacBeth Color standard cards on board have all been damaged by the LED lights, changing the RGB values ont he cards. The MacBeth Method is still retained in Color Balacing Balancing Camera - Old Method MacBeth Color Checker Card section below. We carry a large stock of QP card 101 cards on board, they . They are more heat resistant than the MacBeth card, and much cheaper to replace.
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 QP card 101. 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.
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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!
Adjust Gains
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Master 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. Select the Gains-Black-Shade-Flat tab (Fig. ##)
2. Click Start Grab
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.
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5. Adjust the Master Black Valuevalue until the RGB values are ~40. Qualitatively, this is what's been found to produce a nice image. Please note that the RGB value of the QP card 101 card v4 for this square is 80, but this will be corrected for that value in the TIFF/JPEG correction. Remember to turn off the lights regularly!
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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.others.
9. Click Lights OFF
Figure ##: Adjusting Gains.
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After discussion with JAI we learned the order of corrections should be Pixel Black, Shading, and Pixel Gain. Previously our order was Shading, Pixel Gain, and Pixel Black. The order has been updated here. We were also to told to do all exposure and gain adjustments before doing these three camera corrections. This manual has been updated to reflect those changes.
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Pixel Black Auto Correction
1.
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Assure the lights
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are off
2. Take the lens cap (
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Fig. 33) and place on lens (
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Fig. 34). The lens cap is located in drawer PP-2B.
Figure 33: Lens cap for the camera
Figure 34: Lens Cap being put on camera
3. Click
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Pixel Black Auto Correction. The RGB lines in the Profile graph should be uniform (
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Fig. 35).
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Figure 35: Grab and Profile after the Pixel Black Correction applied.
Shading Correction
1. Take the silicone heat resistant gray mat and clean off any dust with a piece of tape (
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Fig. 36)
2. Place the gray silicone mat on the bench on top of the QP
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card 101, make sure that it is level and perpendicular to the camera’s axis.
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3. Click Lights On, and move the camera over the gray mat.
4. Unfocus the lens on the camera just a little bit (
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Fig. 36). Look at the Profile graph and slightly rotate the lens’ focus until the RGB lines are smoother
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, but still have some variation.
Figure 36
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: The Gray silicone mat being cleaned with tape.
Figure 36B 36: The lens being unfocused.
5.
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The RGB lines should appear “bowed” evenly across profile and centered in the image. If not check the orientation of the gray mat
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, it needs to be flat and perindicular to the camera. This very important!
Figure 37: Grayscale card are corresponding RGB Profile visible.
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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 (
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Fig. 38).
Figure 38: Grab Image grab and profile after the Shading Correction has been applied.
7. Click Lights OFF and wait 60 sec before proceeeding.
Pixel Gain Correction
1. The camera’s lens should still be de-focused
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. Make sure gray silicone mat
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is flat
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2. Click Lights ON
2. Click the Pixel Gain Correction - Flat Method button and move the camera very slowly back and forth
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. 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
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the same
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, but may not be equal to each other
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(
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Fig. 39).
Figure 39: Grab and Profile after the Pixel Gain Correction has been applied.
3. Remove the gray mat and use the QP card 101 to refocus the lens. Move Camera over the mm increments and focus the lens by turning it manually.
4. Click Save. The lights will turn off and the window closes.
Create Correction Curve (Image Corrections)
Note: this is same proceedure as listed in the Calibration Check section above.
Take New Picture
1. Go to Motion > Drive Enable, to re-enable the motor (Figure 40).
Figure 40: Drive enable control highlighted.
2. Go to IMS Main Panel Select DAQ > Image Capture Motion Setup (Figure 41). In this window confirm that speed is set lower than the speed calculated by the Line Trigger Interval
Figure 41: Image Scan Setup Window.
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