The main function of this iPhone application is to create physically based HDR images in which each pixel corresponds to a realistic luminance value. To get more reliable values, there is a very simple way to calibrate the camera.
Therefore, by using this app and then measuring luminance values of each pixel, minimum, maximum, mean, and average values of any area in the scene, or by creating falsecolor images with different scales and color palettes we can evaluate quantity or even quality of light conditions in a realistic space.
Moreover with the help of the GPS navigation unit and motion sensor, this app can create a sun-path diagram and measure total sunlight hours for each specific camera point and view direction in the space.
In the end we can download or even upload HDR images from or to its library via iTunes.
Fixing some bugs in sunlight hours page