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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.
Calibration Check
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3. Click JPEG Corrections tab (Figure 30-3). Adjust the Brightness, Contrast, and Gamma levels (Figure 54-4) to achieve a straight line in the Applied Corrections tab and the ROI Corrected box should have values near 243 250 for the white square and 15 near 50 for the black. 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. (see JPEG corrections cheat sheet in SHIL lab notebook, to be added). The Applied Corrections Graph should be a straight line and the ROI Corrected Box should have values near 243 250. 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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1. Confirm the camera F-stop is set to F/16 or F/22 (Figure 31). F/22 is preferred by the cameral 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 is also acceptableworks for our set up. For hard rock cruises, where 360° whole round scanning is required, a larger F-stop number is required (F/22).
Figure 31: Setting the F Stop on the Camera.
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Figure 37: Remove the corrections and clear gains.
4. In Master Black field, enter 40. (Why? - to raise the sensitivity of the camera's sensors to pick up dark values?)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 is currently being done using 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. The MacBeth Color standard cards on board have all been damaged by the LED lights, changing the RGB values on the cards. The MacBeth Method is still retained in Color Balancing Camera - Old Method MacBeth Color Checker Card section below. We carry a large stock of QP card 101 on board. 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.
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 10 (Figure 38-4). 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!
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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 is described below (The QP card v.4 101 method that was implemented due to high temperature of lights is described at end of this User Guide).
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 below.
Figure 33: Color standard in track in correct orientation.
2. Select the tab RATES and EXPOSURE (Figure 34).
Figure 34: Rates and Exposure window, the tab is highlighted in red.
3. 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.
4. 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.
5. Turn on lights.
6. Click the Start Grab (Figure 36).
Figure 36: 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 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.
8. 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.
9. Adjust the Red Exposure value until the RED value is 245.
10. Adjust the Green Exposure value until the RED/GREEN value is 1.
11. 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.
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
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.
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5. Adjust the Master Black value until the RGB values are ~40~15. 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 black square is 8052, but this will be corrected for that value in the TIFF/JPEG correction. Remember to turn off the lights regularly!
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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 - 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. 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 40) and place on lens (Figure 41). The lens cap is located in drawer PP-2B.
Figure 40: Lens cap for the camera
Figure 41: Lens Cap being put on camera
3. Click Pixel Black Auto Correction. The RGB lines in the Profile graph should be uniform (Figure 42).
4. Remove lens cap when finished.
Figure 42: Grab and Profile after the Pixel Black Correction applied.
Shading Correction
1. Take the heat resistant gray silicone mat and clean off any dust with a piece of tape (Figure 43)
2. Place the heat resistant gray silicone mat on the bench on top of the QP card 101, or anywhere along the bench, 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. 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.
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Figure 44: The lens being unfocused.
5. The RGB lines should appear “bowed” evenly across profile and centered in the image (Figure 45). If not check the orientation of the gray mat, it needs to be flat and perpendicular to the camera. This very important!
Figure 45: 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 46).
Figure 46: Image grab and profile after the Shading Correction has been applied.
7. Click Lights OFF and wait, at least, 60 sec before proceeding.
Pixel Gain Correction
1. The camera’s lens should still be de-focused. 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 47).
Figure 47: Grab and Profile after the Pixel Gain Correction has been applied.
3. Remove the gray mat. Move Camera over the mm increments and focus the lens by turning it manually.
4. Click Lights Off. (at this point I wait 60 secs for lights to cool turn lights back on and check the light gray (white square) RGB values 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 48). This allows the software to control the camera movement.
Figure 48: Drive enable control highlighted.
Image Corrections
Note: this section follows the same steps as listed in the Calibration Check section above.
Take New Picture
1. Place the 3D calibration standard on track as shown (Figure 49). The color squares must be oriented as pictured below, butted against the red reflection bar.
Figure 49: Color standard in track in correct orientation.
2. Open IMS and Click Start.
3. Scan the STND Color barcod label (Figure 50b). Check the ColorChecker Standard box (Figure 50a). With this box selected no corrections are applied to the image so we are able to assess the raw image quality.
4. Click Take A Picture.
5. When the image has finished click Crop and then Save. We use the uncropped image so the crop here is not important.
Figure 50: a) sample information screen with ColorChecker box checked, b) standard barcode being scanned.
6. On the main IMS panel select Instruments and Camera: Image Correction (Figure 51).
Figure 51: Image Correction command selection.
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.
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.
7. Select Open Test Image and select the image you just took (Figure 52-1), 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 52-2)
9. Click Crop (Figure 52-3).
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 52: Image Correction Window. Steps are indicated in the figure.
Tiff Correction
1. Click TIFF Correction Mode (Figure 53-2)
2. Click Uncorrected Image tab. This graph shows the measured red, green, and blue values of the gray scale color squares (Figure 53-3).
3. Click TIFF Correction tab to adjust the shape of the graph. The goal is to have line as straight as possible (Figure 53-4).
4. In the Tiff Correction tab adjust the LUT polynomial order values for the Red, Green, and Blue channels (Figure 53-5). 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 53: 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.
Note: the TIFF correction is applied to both the TIFF and JPEG image but for the JPEG image you can also apply a Brightness, Contrast and Gamma (BCG) correction (See JPEG Correction section below). This is done at the photographer’s discretion. With better balanced LEDs on the new light system you may not have to use the BCG corrections (leave the values at their mid-points).
JPEG Correction
Situations may arise where a JPEG correction should be applied. In the instance of very white or very dark cores, the TIFF images may look good but the JPEG images may look washed out or too dark to view details. JPEG corrections do not alter TIFF image settings. To apply a JPEG Correction follow the steps below:
1. Click JPEG Correction Mode (Figure 54-1)
2. Click Applied Corrections tab (Figure 54-2)
3. Click JPEG Corrections tab (Figure 54-3). Adjust the Brightness, Contrast, and Gamma levels (Figure 54-4) 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.
Figure 54: Steps for JPEG Correction illustrated on image. 1. Select JPEG Correction Mode. 2. Select Applied Corrections tab on graph. 3. Select JPEG Correction to see Brightness, Contrast, and Gamma Corrections. 4. Adjust Brightness, Contrast, and Gamma corrections. 6. Check graph for Linear Relationship. 7. Check the boxes in the Color Checker and compare to RGB values in corrected image.
4. If the values all look good and there are no streaking issues in the images or other unwanted artifacts, you can click Save and no further adjustments are needed. Calibration is complete.
Check on Calibrated Computer
Check the final scan:
1. To double check your calibration under the same scanning conditions as the scientists see, scan an image of the 3D standard without the color checker box selected.
2. Click Crop and Click Save
3. Copy the image to a shared network folder to view on a calibrated computer screen in the Imaging Office. Images located in the C:/DATA/IN/IMAGE folder.
4. Open the TIFF and JPEG in Photoshop in the Imaging Office (calibrated computer).
5. Visually examine each file you just preformed to ensure the colors, neutrals, mid-tone and contrast are true to the real values, and that the scan is free from artifacts. Use the eyedropper tool in photoshop to see the values of pixels (Fig. ## Figure needs to be added).
Camera Height Adjustment
1. Move the camera so it is just on the edge of the grayscale card at the end on the tray. On this card are mm and cm marks on the edge.
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.
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to or subtracted from in order for each pixel to have the average value. (Vendor Manual Reference)
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. 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 40) and place on lens (Figure 41). The lens cap is located in drawer PP-2B.
Figure 40: Lens cap for the camera
Figure 41: Lens Cap being put on camera
3. Click Pixel Black Auto Correction. The RGB lines in the Profile graph should be uniform (Figure 42).
4. Remove lens cap when finished.
Figure 42: Grab and Profile after the Pixel Black Correction applied.
Shading Correction
1. Take the heat resistant gray silicone mat and clean off any dust with a piece of tape (Figure 43)
2. Place the heat resistant gray silicone mat on the bench on top of the QP card 101, or anywhere along the bench, 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. 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 43: 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 45). If not check the orientation of the gray mat, it needs to be flat and perpendicular to the camera. This very important!
Figure 45: 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 46).
Figure 46: Image grab and profile after the Shading Correction has been applied.
7. Click Lights OFF and wait, at least, 60 sec before proceeding.
Pixel Gain Correction
1. The camera’s lens should still be de-focused. 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 47).
Figure 47: Grab and Profile after the Pixel Gain Correction has been applied.
3. Remove the gray mat. Move Camera over the mm increments and focus the lens by turning it manually.
4. Click Lights Off. (at this point I wait 60 secs for lights to cool turn lights back on and check the light gray (white square) RGB values 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 48). This allows the software to control the camera movement.
Figure 48: Drive enable control highlighted.
Image Corrections
Note: this section follows the same steps as listed in the Calibration Check section above.
Take New Picture
1. Place the 3D calibration standard on track as shown (Figure 49). The color squares must be oriented as pictured below, butted against the red reflection bar.
Figure 49: Color standard in track in correct orientation.
2. Open IMS and Click Start.
3. Scan the STND Color barcod label (Figure 50b). Check the ColorChecker Standard box (Figure 50a). With this box selected no corrections are applied to the image so we are able to assess the raw image quality.
4. Click Take A Picture.
5. When the image has finished click Crop and then Save. We use the uncropped image so the crop here is not important.
Figure 50: a) sample information screen with ColorChecker box checked, b) standard barcode being scanned.
6. On the main IMS panel select Instruments and Camera: Image Correction (Figure 51).
Figure 51: Image Correction command selection.
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.
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.
7. Select Open Test Image and select the image you just took (Figure 52-1), 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 52-2)
9. Click Crop (Figure 52-3).
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 52: Image Correction Window. Steps are indicated in the figure.
Tiff Correction
1. Click TIFF Correction Mode (Figure 53-2)
2. Click Uncorrected Image tab. This graph shows the measured red, green, and blue values of the gray scale color squares (Figure 53-3).
3. Click TIFF Correction tab to adjust the shape of the graph. The goal is to have line as straight as possible (Figure 53-4).
4. In the Tiff Correction tab adjust the LUT polynomial order values for the Red, Green, and Blue channels (Figure 53-5). 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 53: 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.
Note: the TIFF correction is applied to both the TIFF and JPEG image but for the JPEG image you can also apply a Brightness, Contrast and Gamma (BCG) correction (See JPEG Correction section below). This is done at the photographer’s discretion. With better balanced LEDs on the new light system you may not have to use the BCG corrections (leave the values at their mid-points).
JPEG Correction
Situations may arise where a JPEG correction should be applied. In the instance of very white or very dark cores, the TIFF images may look good but the JPEG images may look washed out or too dark to view details. JPEG corrections do not alter TIFF image settings. To apply a JPEG Correction follow the steps below:
1. Click JPEG Correction Mode (Figure 54-1)
2. Click Applied Corrections tab (Figure 54-2)
3. Click JPEG Corrections tab (Figure 54-3). Adjust the Brightness, Contrast, and Gamma levels (Figure 54-4) 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.
Figure 54: Steps for JPEG Correction illustrated on image. 1. Select JPEG Correction Mode. 2. Select Applied Corrections tab on graph. 3. Select JPEG Correction to see Brightness, Contrast, and Gamma Corrections. 4. Adjust Brightness, Contrast, and Gamma corrections. 6. Check graph for Linear Relationship. 7. Check the boxes in the Color Checker and compare to RGB values in corrected image.
4. If the values all look good and there are no streaking issues in the images or other unwanted artifacts, you can click Save and no further adjustments are needed. Calibration is complete.
Check on Calibrated Computer
Check the final scan:
1. To double check your calibration under the same scanning conditions as the scientists see, scan an image of the 3D standard without the color checker box selected.
2. Click Crop and Click Save
3. Copy the image to a shared network folder to view on a calibrated computer screen in the Imaging Office. Images located in the C:/DATA/IN/IMAGE folder.
4. Open the TIFF and JPEG in Photoshop in the Imaging Office (calibrated computer).
5. Visually examine each file you just preformed to ensure the colors, neutrals, mid-tone and contrast are true to the real values, and that the scan is free from artifacts. Use the eyedropper tool in photoshop to see the values of pixels (Fig. ## Figure needs to be added).
Camera Height Adjustment
1. Move the camera so it is just on the edge of the grayscale card at the end on the tray. On this card are mm and cm marks on the edge.
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 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.
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Color Balancing Camera - Old Method MacBeth Color Checker Card
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