A Simple and Low-cost Approach to Blood Flow Monitoring Using Speckle Contrast Technique

A laser speckle contrast imaging (LSI) setup has been designed and used to estimate heartbeat rate and microvascular perfusion non-invasively. LSI measurements were performed on the human index finger and thumb during various finger perfusion conditions, such as before and after gently rubbing of a finger or the healing of a small inflammation of the eponychium on the finger. Heartbeat was retrieved with 0.5 to 10ms exposure time using LASCA (Laser Speckle Contrast Analysis) and dLASCA (dynamic Laser Speckle Contrast Analysis) processing methods. Additionally, a noise analysis model for laser speckle contrast imaging was established to evaluate Signal to Noise Ratio (SNR) in speckle imaging and provide a guideline for camera selection and imaging system design.