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2. Back in the IMS control panel go to Instruments > JAI Camera Settings (Figure 2120). The lights turn on automatically when the JAI Camera Setup window opens.
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. Confirm the camera f-stop is set to 16. If not, change it to 16.
4. The lights will turn on when the JAI Camera Window opens. Due to the intensity and heat produced by the LEDs it is best to turn off the lights until ready. Turn off the lights in the software window (Figure 21) or with the physical power switch located behind the monitor (Figure 22).
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Note if the lights are turned off by the harware switch, the lights cannot then be turned on the software command.
Figure 21: Software commands to turn the Lights On or Off.
Figure 22: Hardware Switch to turn power on or off to the lights.
Reset Gains and Corrections
1.Select the Gains-Black-Shade-Flat tab (Figure 23).
Figure 23: JAI Camera Setup Window showing the Gains-Black-Shade-Flat tab. The Gains-Black-Shade-Flat tab is outlined in red.
2. Click the Clear All Gains, Clear Black Gains, Remove Pixel Black Correction, Remove Shading Correction, and Remove Pixel Gain Correction (Figure 24). You will notice all values in the Master and Black gains to zero.
Figure 24: The five clear and remove buttons of interest are outlined in red.
3. In Master Black field, enter 40.
Apply Corrections
We apply three corrections. Find information regarding each correction below:
- Shading Correction - Flat Method -: Shading effects can come from an uneven distribution of light and along the outer edge of the camera lens. Shading is corrected for by averaging the signal across a group of eight pixels to represent the line.
- 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.
- 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)
Shading Correction
- Place the gray card on the tray make sure that it is level and perpendicular to the camera’s axis.
- Turn on the lights, with the same method used to turn off the lights, and move the camera over the gray card.
- Unfocus the lens on the camera (Figure 25). Look at the Profile graph and rotate the lens’ focus until the RGB lines are smooth , then rotate the lens’ focus until the RGB lines are noisy showing the maximum difference between the low and high values. The camera is now focus.
Figure 25: The lens being unfocused.
If you haven’t set the camera’s height now the times to so! See the section Camera Height Adjustment at the end.
4. Now move the camera over the gray card and make sure to de-focus the lens until the RGB line on the Profile graph just become smooth and no more (but still variable) (Figure 26). The RGB lines should appear “bowed” evenly across profile and centered in the image. If not check the orientation of the grayscale card. This very important!
Figure 26: Grayscale card are corresponding RGB Profile visible.
5. 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 27).
Figure 27: Grab and profile after the Shading Correction has been applied.
Pixel Gain Correction
1.The camera’s lens should still be de-focused and grayscale card flat and illuminated.
2. Click the Pixel Gain Correction - Flat Method button. This will take several seconds, don’t click anything else until it is done. The RGB lines should still be flat and the individual RGB are the same (may not be equal to each other) (Figure 28).
Figure 28: Grab and Profile after the Pixel Gain Correction has been applied.
Black Gain Correction
1.Turn off the lights. Lens can be focused or unfocused (doesn’t matter).
2. Take the lens cap (Figure 29) and place on lens (Figure 30). The lens cap is located in drawer PP-2B.
Figure 29: Lens cap for the camera
Figure 30: Lens Cap being put on camera
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There are four main areas in this window:
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