I need to measure luminance vs angle characteristics of an led lamp. I have access to a lux meter and a luminance meter. The problem is, that the luminance meter can only measure luminance within 1 degree, and the lamp is about 100cm x 2cm with LEDs about every 4cm, so the diffusor is not evenly lit. How should I go about measuring the luminance of the whole surface? Should I do many measurements along the lamp and do some kind of average? I even have a robot that could move the luminance meter by increments of 1mm or so. Or maybe should I measure the light with the lux meter and somehow calculate the luminance from that and the surface area?