Fig. 1. Structure of the pyramidal multi-scale GAN

Fig. 2. Structure of generator

Fig. 3. Inception block

Fig. 4. Linear convolutional layer and 1×1 convolutional layer. (a) Linear convolution layer; (b) 1×1 convolution layer

Fig. 5. Residual dense block

Fig. 6. Structure of the discriminator

Fig. 7. Image generated from single image. (a) Image1 of small ship; (b) image2 of small ship; (c) image with noise in background; (d) image of large ship

Fig. 8. Images generated by different networks. (a) Images used for training; (b) images generated by the original network; (c) images generated by the improved network

Fig. 9. Error detection of training on different data sets. (a) Correct test results; (b) SSDD data set; (c) SSDD data set + generated sample data set

Fig. 10. False alarms of training on different data sets. (a) Correct test results; (b) SSDD data set; (c) SSDD data set + generated sample data set

Fig. 11. Missed detection of training on different data sets. (a) Correct test results; (b) SSDD data set; (c) SSDD data set + generated sample data set

Fig. 12. Undetected result after adding the generated data set. (a) Correct test results; (b) SSDD data set; (c) SSDD data set + generated sample data set