NEGATIVE_OBSERVATIONS - discount particles for which observations
should occur (if they were correct) but does not. This function
checks for each sensor in 'sensors' if they should have detected
the target if the particles 'in view' were correct hypotheses.
param: particles - the predicted set of particles
param: observations - the set of observations relevant for the
particles
param: target - the target in question (target struct)
param: sensors - the array of (possibly all) sensor structs
param: resources - the array of own forces
param: discount - the discount to weight the particles
with. (Numeric between 0 and 1, typically above 0.5)
AUTHOR Ronnie Johansson
CREATED 2004-12-22
ALTERED 2005-01-05 - changed call to particles in view
ALTERED 2005-01-18 - minor correction
ALTERED 2005-01-26 - added support for checking observations by
own forces
ALTERED 2005-01-27 - small hack setting weights of paticles "observed" by
own resource to 00001 function neg_weights = negative_observations( particles, observations, ... 0002 target, sensors, ... 0003 resources, discount) 0004 % NEGATIVE_OBSERVATIONS - discount particles for which observations 0005 % should occur (if they were correct) but does not. This function 0006 % checks for each sensor in 'sensors' if they should have detected 0007 % the target if the particles 'in view' were correct hypotheses. 0008 % 0009 % param: particles - the predicted set of particles 0010 % param: observations - the set of observations relevant for the 0011 % particles 0012 % param: target - the target in question (target struct) 0013 % param: sensors - the array of (possibly all) sensor structs 0014 % param: resources - the array of own forces 0015 % param: discount - the discount to weight the particles 0016 % with. (Numeric between 0 and 1, typically above 0.5) 0017 % 0018 % AUTHOR Ronnie Johansson 0019 % CREATED 2004-12-22 0020 % ALTERED 2005-01-05 - changed call to particles in view 0021 % ALTERED 2005-01-18 - minor correction 0022 % ALTERED 2005-01-26 - added support for checking observations by 0023 % own forces 0024 % ALTERED 2005-01-27 - small hack setting weights of paticles "observed" by 0025 % own resource to 0 0026 % 0027 0028 [no_of_particles no_of_attributes] = size( particles ); 0029 0030 no_of_sensors = length( sensors ); 0031 no_of_forces = length( resources ); 0032 neg_weights = ones( no_of_particles, 1 ); 0033 0034 for s=1:no_of_sensors 0035 sensor = sensors(s); 0036 0037 % check if sensor s has detected the target 0038 indices = structfind( observations, 'sensor_id', sensor.id ); 0039 if ~isempty(indices) 0040 % sensor s has made some observations 0041 indices = structfind( observations(indices), 'target_id', target.id ); 0042 if ~isempty(indices) 0043 % sensor s has observed the target - hence, do not discount 0044 % the particles in its view (instead try the next sensor) 0045 continue; 0046 end 0047 end 0048 0049 % sensor s has not detected target - discount any particles 0050 % within its view 0051 indices = particles_in_view( particles, target, sensor ); 0052 if ~isempty( indices ) 0053 neg_weights( indices ) = neg_weights( indices )*discount; 0054 end 0055 end 0056 0057 %% check if any particles are in view of the own forces 0058 for f=1:no_of_forces 0059 indices = particles_in_view_of_force( particles, target, ... 0060 resources(f)); 0061 if ~isempty( indices ) 0062 % neg_weights( indices ) = neg_weights( indices )*discount; 0063 neg_weights( indices ) = 0; % kill the particles 0064 end 0065 end 0066 0067 0068 0069 0070