Seminary project, Geometry of Discreet Spaces, Faculty of Technical Science, Novi Sad, Serbia.
Implementation and demonstration of Rosenfeld and Pfaltz two-pass distance transform algorithm[1].
Demo program has two sub-programs:
- animation
- visualization
...Is designed to demonstrate how the algorithm operates. It steps throught the input image, which is generated to have a square hole in the middle, and shows how the distance value is computed in current pixel (matrix field). Here is an example of the demo (> ./dtdemo -p animation -w=30):
...Works with an arbitrary image (which is easily binarized), uses it and shows in the similar fashion to the animation sub-program, how distance transform is evaluated. Say, using an image like this:
Performs distance transforms, visualizes algorithm evaluation step-by-step, and finally shows the result:
Program is written using D programming language, by utilizing following libraries:
- dcv (computer vision library)
- derelict-ft (freetype wrapper for D language)
It is compiled using D's project manager application, dub. Currently is only tested on MacOS Sierra operating system. LDC compiler v1.1.0 is required. Compile the project with folliwing command:
> dub build --build=reelase --compiler=ldc2
To define the sub-program (animation, visualization), use the -p flag:
./dtdemo -p animation
./dtdemo -p visualization
Each of sub-programs has elaborated help content, when -h flag is added:
> ./dtdemo -p animation -h
Distance Transform Animation.
-s --size Size of the binary image used in the demo.
-b --border Border size (cell count).
-c --cell-resolution Resolution (pixel size) of the matrix cell in the demo.
-m --margin Margin in animation drawing.
-w --wait-time Wait time between each algoritm step in the demo.
-r --demo-result Result type of the demo (show, or write). If write, output must be given.
-o --output Output path.
-h --help This help information.
[1] Rosenfeld, A and Pfaltz, J L. 1968. Distance Functions on Digital Pictures. Pattern Recognition, 1, 33-61.