The Astrophotography Manual, 2nd Edition

Linear Image Processing

It easy to forget that sensor data is inherently linear and that some image processing algorithms, to be effective, depend on unadulterated sensor data.

 

 

The title for this chapter is a reminder that certain image processing tools are better suited to image files before they are stretched. Indeed, the typical workflow shown in fig.1 can equally be called “basic processing”. As mentioned earlier, stretching causes a linear image to become non-linear and certain specialist image manipulation tools are optimized for linear images. These generally fix problems in the original files such as background gradients, color balance and convolution (blurring). If these issues are not fixed early on, subsequent image stretching ...