Fig. 1. The framework of the algorithm

Fig. 2. Dividing the original image into image blocks

Fig. 3. The locally stretched image

Fig. 4. One wide-histogram-body-class image and its grayscale histogram

Fig. 5. One narrow-histogram-body-class image and its grayscale histogram

Fig. 6. The block enhanced image and noise block distribution obtained by adjacent block identification

Fig. 7. Comparison of enhanced effects of the port image by different methods

Fig. 8. Comparison of enhanced effects of the sea surface image by different methods

Fig. 9. Comparison of enhanced effects of the cloud image by different methods