The input of DeltaE is straightforward: a supported test chart should be present inside the image. We expect the target to be present in the upright position, as straight as possible. This restriction has two reasons. One reason is that it speeds up the feature/target detection, the other is that slanted edges have an optimal angle for SFR readout that is approximatelly 5 degrees. So if the target is near that number, your slanted-edge results can be erroneous.
The detection of the targets is both target, location and scale invariant. And literally to some degree rotation invariant. Below the thresholds of the previous invariances are stated.
- Location invariance: the target(s) can be located anywhere in the image.
- Scale invariance: from 100% of the image to ±7% of the surface of the image. Cropping the target out of the image will lead to a significant speed increase.
- Rotation invariance: ±2 degrees. Optimally 0 degrees. We might add more rotation invariance in the future, though this will inevitably decrease processing speed.
- Target invariance: read about the Supported Targets on this wiki. Oficially, only the most modern versions of the targets are supported. Older versions might work but there is no guarantee.
There is a seperate section on support of files and datatypes.
Entirely in sight
If you are unsure how it should be oriented, see DeltaE:Usage