Analysing Particle Tracks for Particle Counting

Dear MATLAB community,

I have analysed a video that charge particles hitting camera sensor creates noisy dots on the video. I can extract the dots that is created by charge particles and applying area threshold I can count the particles at some point. But not every dot on the video represents a particle. The extracted data is too noisy and most of the frame is full of single pixel dots which is not represents a particle. Some of the single pixels constructs a cluster in some shape, this shape is like V or I according the charge particle interaction with the sensor. This clusters generally includes pixel that are not connected each other. I want to count these clusters, because these clusters represents a particle. When I use an area threshold to reject the single dot pixels, I can count some of the clusters but most of them does not counted because the pixels which forms a cluster generally does not connected.

Here in this track we can see that particle hits the sensor

surface at a 45 degree angle but not all the pixels are connected in this example.

Here we can see that most of the frame includes single pixels but the actual

particles represented by the ones which clustered horizontally (2 for this frame) in this case.

On this 2 example frames, clusters includes mostly connected pixels, but generally clusters include pixel groups that are not connected to each other. How can I improve the counting process? How can I count only clustered pixels which are in certain radius and certain shape? Thank you in advance!