Digital Watermarking Of Remote Sensing Images And Vector Graphics

The martial surveying and mapping support will be digital, visual and networked in the condition of the high technology. Its security has been attached more and more importance on. Digital watermarking has been paid more and more attention for its effective use in copyright protection and data security maintenance. Focusing on the images, especially remote sensing images and the vector graphics, this thesis does research on diverse digital watermarking algorithms and some new methods are presented. The main works and creations are as following:1. The principle, character as well as the current research condition of the digital watermarking technology is introduced. Meanwhile, the digital watermarking technology's advantages and possibilities in the digital surveying and mapping support, especially about the remote sensing images and vector graphics, are analyzed.2. A new visible watermarking method for remote sensing images' notification is presented. The watermark can be embedded in spatial domain according to the image's normalized gradient. The method is easy but effective. The embedded watermark is hardly removed and visually outstanding, which can also guarantee the image quality.3. Combined with the character of photogrammetry, based on the remote sensing image's Forstner feature points, a watermarking algorithm is presented. The method takes the Forstner feature points of the remote sensing images as the synchronous benchmarks and a random sequence is embedded in the sub-image's DCT frequency domain centered by the feature points. The watermark can be tested out correctly after the attack of cutting, compression and filtering etc.4. A DWT watermarking method based on the adaptive quantization is presented. The method can define the embedding times and the quantized step adaptively. It is invisible and robust to different attacks, which can protect the copyright of the remote sensing images; meanwhile, it's a blind watermarking.5. It makes a brief analysis about the current type watermarking of the vector graphic. Two algorithms are realized. Taking the gray image and binary image as the watermark, elementary experiments are implemented on the copyright of the vector graphic. The watermark can be embedded and extracted successfully, while ensuring the precision and usability of the graphic.