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A new color-difference formula based on uniform color-difference space presented. CIELAB color space that was revised seemed to create an equal color difference between the adjacent hue lines or chroma lines on the Munsell system. Weighting functions for a new chroma scale and new hue-difference scale adjust the distance in uniform space to the perceived color-difference magnitude of the Munsell system. We called this uniform space a uniform color-difference space. We determined the total color-difference between two color samples with the weighting factor corresponding to the location of the color samples in uniform color-difference space. The Relationships between the total color-difference used in the new formula and the perceived magnitude were performs analyzed through visual perception data sets. The new formula is better than CIELAB, CIE94, and CIEDE2000.

The operating frequency of the inverter based on the resonant performance is fixed at the resonant frequency. Then, it is difficult to regulate the output voltage because the switch-on and -off time can not be set in an arbitrary manner. Therefore, the authors propose the control method of active use of the short-circuit mode to the voltage resonant type of push-pull high-frequency inverter circuit. The characteristics of the proposed inverter are carried out with analytical and experimental manner. The results of the theoretical steady-state analysis agree well with those in the experiment. The circuit efficiency is more than 90% in the wide control range.Further, the inverter is applied to the lighting circuit of electric-discharge lamp. In the lighting circuit made on an experimental basis, the wide range of output control from 83 V to 113 V of the supply voltage and the stable lighting of electric-discharge lamp can be achieved. Then, the circuit efficiency can be obtained over 88%.Thus, the proposed high-frequency inverter by using the short-circuit mode is proved to be of much practical use.