A visualization of 1-D particles filter localization in 2-D space using sensor readings curve.
A robot is located on a long corridor (1 dimensional) and is moving along it. It uses sensor information that helps it find its location.
The following figure shows an example of sensor values (the curve in blue) at each position in the corridor, The robot and its direction are also shown in red. The particles are shown in blue. The robot and each particle can obtain the sensor value from the blue curve based on their position.
The figure below shows the behaviour of the particles along with the robot, with each step, more particles will surround the robot, and more particles will vanish if they're too far from the robot.