Designing Reproducible Test Environments for rPPG: A System for Camera Sensor Response Validation

Remote photoplethysmography (rPPG) enables non-contact vital sign measurements using standard smart devices cameras, opening up the potential of scalable health applications on consumer smart devices. However, rPPG signal quality is highly sensitive to camera sensor characteristics and image processing pipelines, which can vary between devices. This variation limits reproducibility and generalisation of rPPG based algorithms beyond specific hardware platforms. This work presents a reproducible test environment for the validation of the camera sensor response in the context of rPPG signals. A microcontroller driven illumination system and mechanically constrained setup are used to generate controlled, repeatable optical signals and ensure a consistent setup. Two characterisation tests are introduced: a time domain morphology analysis and a frequency domain attenuation analysis. To assess sensor similarity pulse timing consistency, the fitness score and normalised frequency responses are compared. This method is applied to multiple consumer devices and demonstrates consistent camera response patterns under the controlled test conditions. By explicitly addressing the validation of the camera sensor and image processing pipeline of different devices, this work supports the development of deployable, accurate rPPG based vital sign applications across a wide range of consumer devices.