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Pre black level adjustment checklist
Make sure all the projectors are at normal operating temperature
Make sure all projectors are outputting the same luminance, using a bright image
Make sure, all Warp and Blend adjustments are done properly
A: Setup the projector overlap areas
Go to the menu point: Config →Black level adjustment → Black level settings and enable the Black level regioning mode
As using the normal Warp controls, then mark the areas, where the projectorsdo not overlap.
B: Setup the black level blending
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When done, then go to Config → Black level adjustment and select Export Black level masks. When selected then the Warper will export a set of black level masks, used for the black level adjustment.
D: Setup the black level
Go to the menu point: Config →Black level adjustment → Black level settings and enable the Black level regioning mode
Using the Black level adjustment, then turn up the black level, to match the centre of the overlapped area. One thing that might be a bit tricky setting the correct black level – is due to the non white leakage from the projectors. Using the R, G and B trim – then you can adjust the color nuance for the black level uplift. This RGB trim – is only affecting the black level uplift, and therefore not changing the color temperature, when the projector is outputting white.
Depending on the projector setup used in the installation, then you probably need some more black level trimming of the corners of the area towards the overlapped area. This can be done with the Upper left, Lower left, Upper right, Lower rightand Right centre compensation. Adjust these values to get the most uniform black uplift, and color.
E: Intersection trim
The Intersection, is the area, where the projector overlap. On a projector then the projected luminance is non linear from black to approx 4 times the black level. To compensate for this non-linearity, then we need to do a few adjustments, to make a gradient look as smooth as possible.
Firstly, make sure: Config →Black level adjustment → Black level settings and enable the Black level regioning mode is now turned off.
Load the image Gradient – Test in the Warper.
Set the Blacklevel width to 0.1
By adjusting the Blacklevel threshold and the Blacklevel width, then make the adjustments to make the gradient look as close, to the gradient displayed, within the non overlapped areas.
F: Intersection black cutoff
If you are encountering some artefacts in the near black area, then you can use the black cutoff – for removing the near black gradient, that cause the visible artefacts. This should be seen as a last resort quick fix, for in situations, where it’s not possible to re-align the black level compensations.
Additional Notes
Configure the Black Level uplift parameters
Go to the menu point: Config →Black level adjustment → Black level settings
Using the Black level adjustment, then turn up the black level to match the centre of the overlapped area.
Depending on the projector setup used in the installation, you maybe need to adjust the amount of uplift by different amounts to match the corners of the overlapped area. This can be done with the Upper left, Lower left, Upper right, Lower rightand Right centre compensation. Adjust these values to get the most uniform black uplift.
Configure the Black Level rolloff parameters
At higher luminance values, the adjustment at the non-overlapped regions can overshoot their luminance artificially as a result of the Black level adjustment at low luminance values. The parameters Blacklevel Threshold and Blacklevel Width correct the Black level adjustment for higher luminance values by gradually scaling its value to zero after a threshold luminance value.
The parameter Blacklevel Threshold controls the luminance value after which the Black level adjustment decays to zero. The parameter Blacklevel Width controls how fast the adjustment falls off to zero.
Figure 1 illustrates the shape of the Blacklevel rolloff as a function of image luminance. The x-axis represents the image luminance and the y-axis represents the scaling of the Black level adjustment. The Blacklevel Threshold value is 0.5 and the Blacklevel Width is 0.1. Figure 2 shows the effect of changing the Blacklevel Threshold value to a lower value 0.2.
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Advanced mode
By checking the Show advanced the advanced black level settings will be shown.
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