The order of cigarette market is a key issue in the tobacco business system. The anti-counterfeiting code, as a kind of effective anti-counterfeiting technology, can identify counterfeit goods, and effectively maintain the normal order of market and consumers' rights and interests. There are complex backgrounds, light interference and other problems in the anti-counterfeiting code images obtained by the tobacco recognizer. To solve these problems, the paper proposes a locating method based on Susan operator, combined with sliding window and line scanning,. In order to reduce the interference of background and noise, we extract the red component of the image and convert the color image into gray image. For the confusing characters, recognition results correction based on the template matching method has been adopted to improve the recognition rate. In this method, the anti-counterfeiting code can be located and recognized correctly in the image with complex background. The experiment results show the effectiveness and feasibility of the approach.
For high-precision, the grating demodulator based on WDM theory is widely used. In order to satisfy the request of high-speed and high-precision grating demodulator using F-P tuned filter, a high-speed frequency swept laser light source based on semiconductor optical amplifier is designed. This light source uses the work pattern of Fourier Domain Mode Locking and ring cavity geometry. It can provide narrow band tuning light using for grating demodulation, and the tuned frequency is above 4000Hz, the bandwidth is 40nm. Its output light power is higher than 12dBm, and it can greatly improve the speed and SNR of grating demodulator. Under the conditions of swept speed above 4000Hz, the precision of grating demodulator using this light source can reach 2pm.