The effect of different ambient lighting conditions on the grayscale levels on display monitors

Abstract

Purpose: In the medical imaging profession it is extremely important that all the images being reviewed and reported are done so with the utmost expertise and precision. This can only be done if the image being viewed is of an optimal viewing standard. Apart from the image and work station containing any faults in themselves there is a third factor that may cause image degradation. This factor is the viewing environment which is commonly forgotten and not taken care off. Methods: Ambient lighting plays a major role in the correct visualization of grayscale levels and this is what was studied during this dissertation. Three ambient lighting levels where used with one of them being a normal everyday working scenario in a room where radiographs are reported. This was measured to be a LUX level of 100. The other 2 conditions used where higher amount of ambient light, specifiacly 485 LUX and lower LUX level of 4. The findings in each condition where than tested and compared with each other to try and measure briefly the affect of ambient lighting levels. This was done through a monitor luminance test pattern provided by Dry Creek Photo which is the actual physical property that hinders correct image interpretation. Results: It was concluded that as the LUX level increased, a larger discrepancy in the results was found when compared to a lower amount, which still resulted in some loss of information on the image. At 100 LUX, this is the current employed lighting condition, participants tended to see larger amount of grey scales when compared to the 485 LUX yet they saw a lesser amount when compared to the subdued amount of light at 4 LUX. Conclusion: This study concluded that ambient light does affect the visualization of grey scale and the higher the ambient light, the worse the visualization. This statement must however be studied in greater detail as a small population sample was used and results can only give a general overview of the affects of ambient lighting. That is why it is recommended that further tests be done on this matter to achieve a further definite conclusion.