The geometric conditions of diffuse illumination, 8 degree observation, specular light include (SCI) and specular light exclude (SCE) often be employed to measure the surface color of material with different gloss value. The SCE condition is usually realized by setting light trap on the integrating sphere. However, the structure of light trap has its negative influence on the light intensity uniformity, and can led to the inaccuracy of the test results under SCE or SCI condition. Due to the different sizes of the light trap, structures of the measurement instrument will led to inter instrument agreement among the measurement of sample with different gloss. This paper designs a measuring structure to measure the SCE and SCI results simultaneously; proposes a method to calculate the 8 degree gloss value based on the SCE and SCI test result; proposes a computing modal to modify the SCI and SCE measure result based on the 8 degree gloss value, experimental verifying is also carried out. The experimental results demonstrate the structure and modified model effectively reduce the negative influence of light trap. The inter instrument disagreement caused by the geometric dimension of different
light trap is significantly decreased.
Integrating sphere has been widely used in the photoelectric integrating color measurement. Ordinarily,
the measurement caliber of integrating sphere is smaller than the diameter of incidence beam, and
some of the incidence beam irradiate on the inner surface of integrating sphere directly. It introduces
error into the color measurement. The paper establishes the mathematics model of the error introduced
by integrating sphere in color measurement, and has found the way to revise the error. The result
indicates that this method can revise the error which is carried by the mismatch between the
measurement caliber of integrating sphere and the diameter of incidence beam effectively.