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07 ‐ Advanced Features
Optical distortions (radial and decentering) can be obtained by modifying the field rend.camera.distortion.
Optical distortions are modeled in ABRAM using a Brown distortion model with radiometric consistency, not just with a post-processing of the final image, rather modifying the actual ray paths. The energy carried by each point is distributed to a location displaced consistently with the distorted optical ray paths, and only in this way radiometry is conserved. The following image depicts all the possible distortions:
Multiple lights feature is used to simulate Earthshine or really any other planet shining over another. Considering the imaging of the Moon, the earthshine effect is appreciable only at very high phase angles (and long exposure times), given that the reflected radiance from earth is orders of magnitude lower than the emitted radiance from the Sun. The basic idea is to coadd the image of Earthshine to the original image of the Moon. the Earthshine image is generated setting the light position equal to the position of the Earth and to set the the light spectrum equal to the radiance reflected by Earth.
The smearing model is used to simulate charge transfer for CCD detectors. This effect is typically only visible when modifying the image colorscale to a small domain as the DN noise level is similar to the background. Example for a 12 bit image (max DN = 4096):
The blooming model is used to simulate charge spilling due to over-saturation of the detector:
Aberrations can be used to simulate higher-harmonics optical effects, even if most of the times blur is the only effect you need:
