Introduction

We propose a frameworg to extract geometric structures from images using Delaunay Point Process (DPP).
This framework is based on the paper "Extraction Geometric Structures in Images with Delaunay Point Processes" (TPAMI 2019)

Dependencies

Qt5, Glm, Glew, Eigen3, OpenCV, CGAL and SuiteSparse

Configuration files

General parameters

You can modify the parameters of DPP modifying the file (data/)config/DPP_parameters.conf. The default content of this file is the following:

• sampling_mode GUIDED: set the sampling mode to UNIFORM of GUIDED. For GUIDED sampling, the algorithm use the image Datacost::img_grad which has to be initialized inside the method DataCost::ini_from_file.
• active_kernel BD_M_L: specify which kernel the algorithm will use. Possible values are BD_M_L, BD_M, BD_L, BD, B_L, D_L, M_L, B, D, M, L. B = birth kernel, D = death kernel, M = point relocation kernel (ie move), L = mark alteration kernel (ie change label)
• sampling_domain 0.0 0.0 1.0 1.0: the domain for sampling points when sampling_mode is set to UNIFORM. The two first parameters should be 0.
• expected_number_of_point 1000: it it the the parameter lambda of equation 5 of our paper which represents the parameter of the discrete Poisson distribution.
• T_0 0.01: it is the initial temperature of the RJMCMC defined in Algorithm 1 and used in equation 6
• alpha 0.99998000: it is the parameter of the geometric decrease of the temperature which is used in equation 6
• number_of_maximum_iteration 2000000 we stop the algorithm when the maximum number of iteration is reached.

Application specific parameters

You can modify application specific parameters modifying the file (data/)config/app_blablabla_parameters.conf. This file is loaded by the function DataCost::load_app_specific_parameters called by the system at the beginning.

Main structure

Main structures for DPP are defined in main.h. There is one to create console application and another one to create application with an user interface:

• struct delaunay_point_process
• struct delaunay_point_process_gui

The first templates of these structures are:

• CostVertex
• CostEdge
• CostFace
• DataCost

Then the structure delaunay_point_process_gui is templated by GuiRendering
and then the two structures are templated byLabel

Label

This object correspond to the type of the label. The default type is int. If you want to store in the primitive of the Delaunay triangulation some temporary value, you can store them here.

DataCost

DataCost contains all parameters used inside Cost* classes. You can add new parameters if you want.
DataCost contains several methods:

• ini_from_file is called at the begining of the algorithm to initialise the algorithm and mainly the distribution used by the kernel Birth to draw a new point on the Image domain.
• load_app_specific_parameters: is called at the begining of the algorithm to initialise application specific parameters.
• save_output is called at the end of the algorithm to save results.
• operator_label is called by the system when the kernel mark alteration is invoked. This method redirects the program to the right mark alteration kernel which differ from an application to another one
• process_user_classes_input is called by the system when the user click on recompute proba.
• is_in_img and is_not_valid are called by the system to check if an integer pixel is on the image or if a floating point pixel is one of the four exterior point which support the all Delaunay triangulation.

Cost*

• p_label(Triangulation& t, Primitive& p, DataLabel& dataLabel) compute the probability that the primitive p is labelled by dataLabel.label and put this probability inside dataLabel.p_label. This function is called when the primitive or an adjacent primitive is modified. You can update specific extra temporary variable of DataLabel you used in the cost function.
• recompute_label. This method return a label. This method is called to initialize new primitives.
• cost. This method return the energy associated to the current primitive.

GuiRendering

This class contains a method ini_vbo_get_alpha which transfert the meshe and the labels to the gpu.
Attributs of this class are used by the class MainWindows to add on the interface some control on specific-application parameters.