| 摘要 |
PURPOSE:To obtain a light-and-darkness signal and color tone signal with simple constitution by irradiating a body to be detected with at least two kinds of light emission spectra by turns, by receiving transmitted or reflected light, and then by processing the photdetection output. CONSTITUTION:Light emitting elements 5 and 6 are turned on by turns to irradiate body to be detected 20 with two different kinds of spectrum light by turns. Light penetrating detected body 20 is received by photodetector 8, whose photodetection signal is amplified by amplifier 9 and then sent to low-pass filter 10 and high-pass filter 11. Low-pass filter 10 outputs a light-and-darkness signal and the output of high-pass filter 11 is multiplied by excitation signals of light emitting elements 5 and 6 by multiplying circuit 12 to obtain a color tone signal through low-pass filter 13. |
