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Synthetic Image Generator/SIG.m 0 → 100644
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%% Girish K. Jankee %%%%%%
%%%%%% University of Southampton %%%%%%
%%%%%% April 2019 %%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% This is the main script which generate stereoscopic PIV images. You are
% required to ONLY change the directory and the variables prior to usage.
%
% Any other changes to the script should ONLY BE MADE AFTER DISCUSSION WITH
% THE AUTHORS. WHENEVER MAKING USAGE OF THIS SCRIPT, PLEASE REFER TO AND CITE
% DOI OF THE FOLLOWING PAPER:
% "Comparison between object and image plane cross-correlation for
% stereoscopic PIV in the presence of pixel locking", Girish K. Jankee and
% Bharathram Ganapathisubramani, Experiments in Fluids, February 2020
% DOI: 10.1007/s00348-020-2916-x
% -------------------------------------------------------------------------
% Version 1.0 June 2019
% -------------------------------------------------------------------------
%% Tidy workspace
close all
clearvars
clc
drawnow
tic
warning off
%% User-defined variables
% Directory
root_in_dir = 'I:\Paper 2\Raw Images\'; % Define the root directory where folder will be created
raw_out_dir = [root_in_dir 'Raw Images 1\']; % Path where the synthetic images will be saved
% Calib_dir = ['\\filestore.soton.ac.uk\users\gkj1g12\mydocuments\PhD\Paper 2\Synthetic Image Generator v4\'];
% Calib_file = 'pinhole.mat';
Calib_dir = 'I:\Validation_case7\Properties\Calibration\'; % Define the directory of the calibration file
Calib_file = 'MarkPositionTable.xml'; % Filename which contains the marker locations and properties of calibration
file_out = 'B'; % Filename for generated images
ext_out = '.tiff'; % Format of generated images
% Make directory if it does not exist yet
if exist(raw_out_dir,'dir')~=7
mkdir(raw_out_dir);
end
% Variables
n = 1; % number of synthetic images to be generated
Calib_type = 1; % (1/2) Select 1 for 3rd order polynomial or 2 for Camera pinhole model
sizex = 200; % Dimension of volume to be generated in x-direction [mm]
sizey = 100; % Dimension of volume to be generated in y-direction [mm]
sizez = 1; % Dimension of volume to be generated in z-direction [mm]
Param.density = 70; % Number of particles per mm3
Param.Z = 0.25; % Thickness of laser sheet [px]
Param.dp = 1; % Mean particle diameter [px]
Param.ddp = 0.68; % Standard deviation of the particle diameter [px]
Rot_angles = [0,0,0]; % Vector containing Euler angles that describe 3D rotation;
Trans.x = 0; % Translation in x-direction [px]
Trans.y = 0; % Translation in y-direction [px]
Trans.z = 0.5; % Translation in z-direction [px]
Scale = 1; % Uniform scaling factor to apply to frames (if needed)
noise.app = 0; % Select whether to apply noise or not to the images (0/1)
noise.mean = 0; % Mean of noise signal to add to the images
noise.var = 0.005; % Variance of noise signal to add to the images
turb.mean = 0; % Mean of turbulence profile
turb.var = 0.2*(40/sizey)*Trans.z; % Variance of turbulence profile (default: 10% of max translation)
sv = 0; % (0/1) Select 0 if you do not want to save the images and 1 if you want to save the generated images
plot = 1; % (0/1) Select 0 if you do not want to plot the images and 1 if you want to plot the generated images
%% Calibration and sensor size determination
if Calib_type == 1
% Retrieve calibration markers coordinate for both left and right camera
calibname = [Calib_dir Calib_file];
[Coord,corners_cam] = retrieve_marker_coord(calibname);
% Find coefficients of 3rd order polynomial for transformation from object plane to image plane
[Calib_XL,Calib_YL,mapping_fun] = poly_fit(Coord.Left); % Calibration coefficients for left camera
[Calib_XR,Calib_YR,~] = poly_fit(Coord.Right); % Calibration coefficients for right camera
Transform.Leftcam{1,1} = Calib_XL;
Transform.Leftcam{1,2} = Calib_YL;
Transform.Rightcam{1,1} = Calib_XR;
Transform.Rightcam{1,2} = Calib_YR;
% Sensor size
sensor.x = corners_cam(1,2); % Size of sensor in x direction [px]
sensor.y = corners_cam(2,3); % Size of sensor in y direction [px]
else
% Load calibration properties and projection matrix
load([Calib_dir Calib_file]);
% Retrieve left and right camera transformation from projection matrix
Transform.Leftcam = camera(1).calib.P;
Transform.Rightcam = camera(2).calib.P;
% Sensor size
sensor.x = size(camera(1).i_axis,2); % Size of sensor in x direction [px]
sensor.y = size(camera(1).j_axis,2); % Size of sensor in y direction [px]
end
%% Define the density of particles in the volume
numP = round(Param.density*(sizey)*(sizex)*(sizez));
%% Define laser sheet intensity
z0_pre = randn(numP,1); %distributed sheet intensity for frame 1
randn('state', sum(100*clock));
z1_pre = randn(numP,1); %distributed sheet intensity for frame 2
z0 = z0_pre*0.5 + z1_pre*0.5;
z1 = z0_pre*0.5 + z1_pre*0.5;
I0 = 255*exp(-(Param.Z^2./(0.125*z0.^2))); %particle intensity for frame 1
I0(I0>20) = 255;
I0(I0<20) = 0;
I1 = 255*exp(-(Param.Z^2./(0.125*z1.^2))); %particle intensity for frame 2
I1(I1>20) = 255;
I1(I1<20) = 0;
%% Particle diameter distribution
randn('state', sum(100*clock));
d1 = randn(numP,1)/2; %particle diameter distribution
d1 = Param.dp + d1*Param.ddp;
d1(d1<0) = 0;
rd1 = -8.0 ./ d1.^2;
%% Main script
%Create waitbar
wb = waitbar(0,'1','Name','SIG in process...','CreateCancelBtn','setappdata(gcbf,''canceling'',1)');
setappdata(wb,'canceling',0);
for i = 1:n
% Check for clicked Cancel button
if getappdata(wb,'canceling')
break
end
% Update waitbar and message
waitbar(i/n,wb,[sprintf('%12.1f',i/n.*100) '%']);
% Generate initial volume of particles
[ini,Cam1]=volume_gen(sizex,sizey,sizez,numP,Transform,Calib_type);
% Place particles in frame
% Left camera
[A.Frame1] = frame_gen(Cam1.L,d1,rd1,numP,sensor,I0);
% Right camera
[B.Frame1] = frame_gen(Cam1.R,d1,rd1,numP,sensor,I0);
% define turbulent intensity
pdx = makedist('Normal','mu',turb.mean,'sigma',turb.var);
pdy = makedist('Normal','mu',turb.mean,'sigma',turb.var);
pdz = makedist('Normal','mu',turb.mean,'sigma',turb.var);
tx = truncate(pdx,-turb.var,turb.var);
ty = truncate(pdy,-turb.var,turb.var);
tz = truncate(pdz,-turb.var,turb.var);
turb_intx = random(tx,[numP,1]);
turb_inty = random(ty,[numP,1]);
turb_intz = random(tz,[numP,1]);
% Apply shear flow
for k = 1:numP
disp.X1(k,1) = ini.X1(k,1) + turb_intx(k,1);
disp.Y1(k,1) = ini.Y1(k,1) + turb_inty(k,1);
disp.Z1(k,1) = ini.Z1(k,1) + (Trans.z./sizey)*ini.Y1(k,1) + turb_intz(k,1);
end
% for k = 1:numP
% disp.X1(k,1) = ini.X1(k,1);
% disp.Y1(k,1) = ini.Y1(k,1);
% disp.Z1(k,1) = ini.Z1(k,1) + (Trans.z./sizey)*ini.Y1(k,1) ;
% end
% Generate displaced volume of particles
[~,Cam2]= volume_gen2(disp,Transform,Calib_type);
% Place particles in frame 2
% Left camera
[A.Frame2] = frame_gen(Cam2.L,d1,rd1,numP,sensor,I1);
% Right camera
[B.Frame2] = frame_gen(Cam2.R,d1,rd1,numP,sensor,I1);
% Apply noise
if noise.app == 1
Frame1.L = imnoise(A.Frame1,'gaussian',noise.mean,noise.var);
Frame1.R = imnoise(B.Frame1,'gaussian',noise.mean,noise.var);
Frame2.L = imnoise(A.Frame2,'gaussian',noise.mean,noise.var);
Frame2.R = imnoise(B.Frame2,'gaussian',noise.mean,noise.var);
else
Frame1.L = A.Frame1;
Frame1.R = B.Frame1;
Frame2.L = A.Frame2;
Frame2.R = B.Frame2;
end
% Save images
if sv ==1
imwrite(Frame1.L, [raw_out_dir file_out sprintf('%05i',i) '_1L' ext_out],'Compression','none');
imwrite(Frame2.L, [raw_out_dir file_out sprintf('%05i',i) '_2L' ext_out],'Compression','none');
imwrite(Frame1.R, [raw_out_dir file_out sprintf('%05i',i) '_1R' ext_out],'Compression','none');
imwrite(Frame2.R, [raw_out_dir file_out sprintf('%05i',i) '_2R' ext_out],'Compression','none');
end
end
% Delete waitbar
delete(wb)
% Plot last set of generated images
if plot == 1
figure(1)
imagesc(Frame1.L)
colormap(gray)
figure(2)
imagesc(Frame2.L)
colormap(gray)
figure(3)
imagesc(Frame1.R)
colormap(gray)
figure(4)
imagesc(Frame2.R)
colormap(gray)
end
\ No newline at end of file
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