A system configured to receive and improve the quality of image data used to determine the condition of a vehicle driver, the condition of the vehicle driver being determined by deriving from the image data a condition signal associated with a biological or physiological condition of the vehicle driver related to biological measures including at least one of the heart rate of the vehicle driver and the breathing rate of the vehicle driver, the system comprising: a camera positioned to detect image data of the vehicle driver; non-image sensors for providing non-image sensor data regarding biological measures of the vehicle driver; a lighting system (206, 310) positioned to illuminate an interior of the vehicle; a controller configured to receive the detected image data and to receive the non-image sensor data from the non-image sensors; wherein: the controller is configured to determine the condition of the vehicle driver based on the received image data; the controller is configured to make a determination of the quality of the image data; and the controller is configured to, if the controller determines that the received image data has a poor image quality such that the biological measures of the vehicle driver cannot be derived from the received image data, selectively either alter the lighting system based on the determined image data quality to improve image data quality or determine the condition of the vehicle driver based on both the image data of the vehicle driver and the non-image sensor data from the non-image sensors by supplementing the image data with the non-image sensor data. a camera positioned to detect image data of the vehicle driver; non-image sensors for providing non-image sensor data regarding biological measures of the vehicle driver; a lighting system (206, 310) positioned to illuminate an interior of the vehicle; a controller configured to receive the detected image data and to receive the non-image sensor data from the non-image sensors; wherein: the controller is configured to determine the condition of the vehicle driver based on the received image data; the controller is configured to make a determination of the quality of the image data; and the controller is configured to, if the controller determines that the received image data has a poor image quality such that the biological measures of the vehicle driver cannot be derived from the received image data, selectively either alter the lighting system based on the determined image data quality to improve image data quality or determine the condition of the vehicle driver based on both the image data of the vehicle driver and the non-image sensor data from the non-image sensors by supplementing the image data with the non-image sensor data. the controller is configured to determine the condition of the vehicle driver based on the received image data; the controller is configured to make a determination of the quality of the image data; and the controller is configured to, if the controller determines that the received image data has a poor image quality such that the biological measures of the vehicle driver cannot be derived from the received image data, selectively either alter the lighting system based on the determined image data quality to improve image data quality or determine the condition of the vehicle driver based on both the image data of the vehicle driver and the non-image sensor data from the non-image sensors by supplementing the image data with the non-image sensor data.