Mathematical morphological operators implementation in CUDA (parallel version), three versions are avaiable: check out branches. A report is included.
An implementation of morfological operators, in order to compare it with the sequential C++ version (here) and measure speedup.
Code works with .ppm B/W images, extracting only the first channel if multiple channels are detected. Results are also .ppm images, timings are always saved in a .csv file.
Regarding operators, multiple shapes are avaiable: you can even set a custom sizes. Check out StructuringElement.h.
MorphableOperators.h contains implementations of some well know tranformations: erosion, dilatation, opening, closing, top-hat and bottom-hat transform. Derived transformations were implemented calling base transformations methods.
Every version stores the structuring element in constant memory.
master: branch use shared memory for store locally each tile, compute the transformation on that tile and writes back in global memory. Tile's paddin is managed by two threads.
optimized-padding: works as above, except for padding's loading: this time all threads on the border work to load the padding.
no-shared-memory: pretty explicative, works without shared memory. Every read and write operation is done on global memory.
GPU timings were recorded on a Nvidia K80, CPU timings on a AMD Ryzen 1600; every GPU version was tested varing input tile's size from 8 to 32. 5 images from 400x400 5000x5000 were used for the test, below a table with three images and tile's size set to 16, full data can be found on the report.
Timings are in seconds.
| Img res | Operation | CPU | master_16 | optimized-padding_16 | no-shared-memory_16 |
|---|---|---|---|---|---|
| 432x596 | Erosion | 0,0188 | 0,0005 | 0,0004 | 0,0003 |
| 432x596 | Dilatation | 0,0380 | 0,0011 | 0,0008 | 0,0006 |
| 995x1134 | Erosion | 0,4960 | 0,0142 | 0,0112 | 0,0082 |
| 995x1134 | Dilatation | 1,0288 | 0,0284 | 0,0225 | 0,0164 |
| 4871x6466 | Erosion | 2,0761 | 0,0584 | 0,0464 | 0,0339 |
| 4871x6466 | Dilatation | 4,1218 | 0,1180 | 0,0935 | 0,0678 |