2. Tone Mapping
- Apply general knowledge about raster image and image formats.
- Understand the issues with the dynamic range of an image, and how and where toapply tone mapping techniques.
- Design and implement image loading and saving (that will be used for later assign-ments).
The assignment consists in develop a set of tone mapping strategies as stand alone applications which have as parameters the input HDR image, the output LDR image and the corresponding parameters of the tone mapping operator. In memory, the image will is stored as a 2D arrayof RGB tuples in floating point precision (this will avoid losing information when loading andsaving the image). The tone mapping operators are the following:
- Clamping: Discard all values greater than 255 (1 in floating point precision).
- Equalization: Linear transformation of values from minimum to the maximum(normalization).
- Equalize and clamp: Combine both of the above according to aclampingparameter.Note that the previous two operators can be considered particular cases of this one.
- Gamma curve: Apply a gamma curve to all the values (you need to equalize first).
- Clamp and gamma curve: Apply a gamma curve after clamping the values (youneed to equalize first). Note that all previous operators can be considered particular
Image format ppm has been used for writing the output of the ray tracer into animage. It is a very simple text file that can be read by most viewers and is very simple to read and write.
With this HDR format, the maximum of any image would be only 1. Instead an optional comment line has been enabled such as #MAX=18.35 that sets up the real maximum of the image as a real number. It has been provided a set of HDR-ppm images as supplemental material of this assignment in order to test loading and saving and the different operators.
In order to test the tone mapper implemented a set of images in ppm format, not visible initially, have been submitted to different operations of the tone mapper explanied before. These are the results obtaied after doing the tests.
