Object classification of remote sensing images based on optimized projection supervised discrete hashing

Recently, with the number of large-scale remote sensing (RS) images increasing, the demand for large-scale RS image object classification is growing, and many researchers are interested. Hashing, as a result of its low memory requirements and high time efficiency, has widely solved the problem of large-scale RS images. Supervised hashing methods mainly leverage RS image label information to learn hashing function; however, the similarity of the original feature space cannot be well preserved, which cannot meet the accurate requirements of RS images object classification. To address the aforementioned analysis, we propose a method named optimized projection supervised discrete hashing (OPSDH), which jointly learns optimized projection constraint and discrete binary codes generation model. It uses an effective optimized projection method to further constraint on the supervised hashing learn, and generated hash codes preserve the similarity based on the data label while retaining the original feature space's similarity. The experimental results show that OPSDH reaches improved performance compared with existing hashing methods and demonstrates that the proposed OPSDH is more efficient for operational applications. (C) 2021 Society of Photo-Optical Instrumentation Engineers (SPIE)