A Display Mode viewer is used to improve the visibility of an image, but without altering its pixel data in any way, similarly to what DS9 scale does.
- Linear: the default mode in Siril. Pixels are displayed from the darkest to the brightest in a linear scale.
- Logarithm: the logarithmic scale. The operation emphases simultaneously information in faint and bright levels of the image.
- Square root: the square root of each pixel. The result is close to the logarithm mode's.
- Squared: squared of each pixel. What can be seen with this mode is mainly the brightest part of the image.
- Asinh: the inverse hyperbolic sine is commonly used, it reproduces the perceptual ability of the human eye, which can accommodate to perceive dramatically different levels of brightness simultaneously. Asinh is close to the logarithm mode but has a better behaviour around zero.
- AutoStretch: Siril performs an automatic screen stretch.
- Histogram: the histogram equalisation. It increases the contrast of the image by increasing the dynamic range of intensity given to pixels with the most probable intensity values. It is very valuable to evaluate all the signal contained in the image.