Choice of colour space in illuminance measurement with a low-cost digital camera

Poor colour rendering characteristic of a low cost camera results in poor colour recognition, especially with images taken under non-white illumination. A simplified colour calibration process for a digital Web cam to be used for indoor illuminance measurement, enabling automatic, realtime, simultaneous measurement of illuminance of an indoor space at multi-locations based on its video image is proposed. Lab test results on 12 colours yielded 88% accuracy, which can be further improved in future work.