Melanoma is one of the most serious skin cancers in the world. As circulating tumor cells have been proved to be an important marker of early metastasis of cancer, the detection of circulating tumor cells of melanoma is of great significance for early diagnosis and the monitoring of tumor progression. In vivo photoacoustic flow cytometry (PAFC) is constructed to achieve real-time and non-invasive detection of circulating melanoma cells in vivo. However, as the photoacoustic signals acquired in the detection process are disturbed by various kinds of noise, it is difficult to accurately distinguish the photoacoustic signals of background and circulating tumor cells by the traditional triple mean square deviation method. Therefore, a photoacoustic signal classification method is proposed based on convolutional neural network, which can greatly improve the accuracy of detection. Features of signals are extracted by the convolutional neural network to distinguish photoacoustic signals of melanoma cells and background. We construct a convolutional neural network based on one-dimensional input signals. For training the classifier, a large number of samples are selected. The accuracy rate in the test set can reach 95%. Besides, a neural network is built based on VGG16 model and transfer learning, and the trained classifier can realize the accuracy of 98% in the test set. Experiments show that the method of photoacoustic signal classification based on convolutional neural network greatly improves the accuracy of signal classification, and realizes the rapid and accurate analysis of a large number of data.
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