This paper investigates the use of OpenMP for parallel post processing in obejct detection on personal Android devices, where resources like computational power, memory, and battery are limited. Specifically, it explores various configurations of thread count, CPU affinity, and chunk size on a Redmi Note 10 Pro with an ARM Cortex A76 CPU. The study finds that using four threads offers a maximum post processing speedup of 2.3x but increases overall inference time by 2.7x. A balanced configuration of two threads achieves a 1.8x speedup in post processing and a 2% improvement in overall program performance.