用CHROMA METER CR-400色差仪测出了皮蛋的L、a、b值,要求怎么求△E,L标准、a标准、b标准是多少

英语翻译
The color of the dried chips was measured using a Chroma Meter
.The colorimeter was calibrated with a certified standard white plate.For each treatment,one measurement was performed at random locations on a slice
while the data were taken for five slices.The color parameters
were reported in CIE-lab scale as L*,a* and b*,where L* is the luminance
or lightness component,and parameters a* (from green to
red) and b* (from blue to yellow) are the two chromatic components.