The direct measurement particle temperatures and advective losses from solid particle receiver has been a topic of necessary interest to de-risk the technology and improve its performance. Due to the flow's transient and stochastic nature it has presented a challenge to traditional thermometry and metrology methods. In this work, a non-intrusive imaging methodology previously developed is applied to the Sandia's falling particle receiver during on-sun tests to collect image sets which could help estimate the average particle temperature and particle egress rate from the system. Further additions to the technique are presented to permit the estimation of plume (air and particles) egress rate and total advective heat losses during on-sun operation. The falling particle receiver testing campaign in 2020 and 2021 allowed the team to capture multiple flow configurations and environmental conditions which to build a large database of data captures with different characteristics. Finally, the results captured were used to complete a regression study to gain further insight on the factors which impact the particle egress and the receiver's efficiency. Particle temperature, receiver flow configuration and wind speed were found to be the most impactful factors in the study.