Display
ISETCam has tools to evaluate image system components and overall image processing quality. To measure the quality of an RGB image, it is essential to calculate how the image would appear on a display device. After all, nobody looks directly at RGB values - they are always displayed and the eye responds to the spectral radiance distribution. Hence, the display model must be part of simulation.
ISETCam includes a display structure, just as it has a scene, oi, sensor, and ip structure. Like the other structures, the display structure represents the physical properties of a display model, including the spectral radiance of the primaries and the dots per inch. Like the othe structures, the display model comes with the usual functions (displayCreate, displaySet/Get, displayWindow, and displayPlot).
We use these to perform certain calculations, such as diplay gamut or to bring up a window with the display parameters.
It is possible to convert from a display model with an image into a scene representation (spectral radiance) via the sceneFromFile calculation.
The display data and methods allow the user to incorporate the calibrated display models when evaluating image quality. When no display is explicitly defined, such as when we render the images in the scene, oi, and ip windows we use an implicit display color model: sRGB. Explicit displays are typically used for image quality metrics, such as CIELAB and Spatial CIELAB. We are aware, of course, that not many engineers follow this path, and the only use RGB values without accounting for factors such as the physics of the display device or the viewing distance from the display device. This is true, for example, of SSIM which is only a luminance metric in any event.
For a deeper dive into the display methods, visit the display model page. There is also a page with links to the display tutorials and scripts. These links include many examples of computations that account for display properties.