Enhancing precision in line-scan chromatic confocal sensors through bimodal signal pattern

The peak feature of spectral power distribution signals from conventional chromatic confocal measurement degrades significantly as the scanning mode change, which is detrimental to the accuracy and precision of the line-scan chromatic confocal sensor. A bimodal signal pattern is proposed in this paper to solve the peak feature degradation problem. In the bimodal signal pattern, two peak features with smaller full width at half maximum are obtained by offsetting the filter slit. This results in more robust feature localization and more accurate measurement output from the line-scan sensor. Precision calibration experiments conducted on a self-developed line-scan chromatic confocal sensor reveal a remarkable 40% improvement in precision when employing the bimodal signal pattern compared to the traditional unimodal signal pattern with the same hardware configuration.