Regular monitoring of blood oxygenation is important for disease prevention and treatment. Image photoplethysmography (IPPG) technology is a non‐contact physiological parameter detection technology, which has been widely used in blood oxygenation detection. However, traditional imaging devices still have issues such as low detection accuracy, narrower receiving spectral range. In this paper, we proposed two improved detection methods based on the dual‐wavelength measurement principle, that is, dual‐band IPPG signal ratio method and dual‐band IPPG signal AC/DC method. To verify the effectiveness of the two methods, we used different heartbeat period IPPG signals as sample data sets, and combined PLS and RF algorithms for model training, thus obtaining the best data processing method. The experimental results showed that the dual‐band IPPG signal AC/DC method can effectively reduce the model training time. This method meets the strong demand for non‐contact blood oxygen measurement and provides a new measurement idea.