False-Color and Diagnostic Imaging
False color maps measured intensity, often outside visible light, to a color scale so the eye can read what it could not otherwise see.
Color as measurement
Many diagnostics record intensity the eye cannot see directly: infrared, ultraviolet, X-ray, or neutron counts. False-color imaging assigns these measured values to a color scale, turning invisible signal into a readable image. Unlike a photograph, the color carries quantitative meaning and must be treated as data.
Honest false color
- State the physical quantity and its range; false color without a scale bar is uninterpretable.
- Use a perceptually uniform map so intensity steps read evenly (see Color Maps).
- Report integration time and any gain, since brightness depends on them.
Calibration
A camera or detector reading is not the physical quantity until calibrated: dark current, flat-field response, and geometry all intervene. A visualization should show calibrated values or clearly label raw counts. Saturated pixels must be flagged, not shown as merely bright, because saturation means the true value is unknown.
Geometry and line of sight
Imaging diagnostics often integrate along a line of sight, so a bright pixel is a projection, not a local value. When a local field is reconstructed by inversion, show both the image and the reconstruction and mark where the inversion is poorly constrained (see Diagnostics Visualization).
Kronos use
Simulated imaging and neutron-detector signals are shown in perceptually uniform false color with stated quantities, scales, and integration context, kept distinct from reconstructed local fields.