VISUAL LUMINANCE MEASURING APPARATUS

摘要

PURPOSE:To calculate visual luminance by determining a luminance difference threshold from an equivalent screen luminance Lev or a luminance Lo of a visual object. CONSTITUTION:An image of an object 1 is formed on photo detectors 7 and 11 and a finder 5. A signal of a visual object luminance Lo from a photo detector 7 is amplified 8 and converted into a digital signal with an A-D convertor 9. An equivalent screen luminance Lev signal from the photo detector 11 is amplified 12 and converted into a digital signal with an A-D convertor 13. According to a digital output of the convertor 9 corresponding to a measured value of the luminance Lo, a memory 14 is addressed to convert the contents therein into a coding signal. On the other hand, according to a digital output of the convertor 13 corresponding to a measured value of Lev, a memory 15 is addressed to convert the contents therein into a coding signal corresponding to a luminance difference threshold including Lev and a fouea adaptive luminance value. The coded signal outputs of the memories 14 and 15 address a visual luminance calculation memory 16 to output a visual luminance 13.