基于视觉MIMO技术的动态隐藏信息传递技术研究

发布时间：2018-08-31 09:55

【摘要】：视觉MIMO是利用发光阵列上的多个发光元件为光发射器,利用数码摄像机图像传感器上的多个像素点为光接收器,产生多个并行信道,进而实现多输入多输出的通信系统。它与射频无线通信的MIMO思想相近,但是本质上有很大的差别。由于光波的高度定向性,视觉MIMO系统可以避免射频通信中的同信道干扰以及易被窃听等问题。而且由于摄像机自身的大视场,与传统的无线光通信相比,视觉MIMO还可以满足移动通信的需求,因而具有重大的研究意义及广阔的发展空间。本文利用视觉MIMO技术来实现动态隐藏信息传递,它是将要发送的信息嵌入到电子显示屏的图像中,使其对人眼不可见,而通过摄像机拍摄,经图像处理后,可以提取出发送的信息。这样就可以在不改变电子显示屏原有用途的基础上,增加其通信的功能,使电子显示屏具有双重职能。这样就可以大大减少在通信设备上的资金投入,降低开销。其中如何实现动态隐藏信息的嵌入与提取,就是本文的主要工作。首先,根据视觉MIMO技术的原理,建立了简单的计算机显示屏——数码摄像机通信系统。并且详细介绍了在数字图像处理过程中需要应用到的计算机视觉算法,其中包括多分辨率分析、特征检测与匹配、图像分割和图像几何校正。其次,在发送端,通过拉普拉斯金字塔分解将原始图像分成四个子图像,将要发送的信息通过乘法运算嵌入到顶层子图像中。由于顶层子图像为低频信息,人眼对其不敏感,这样可以保证在经过拉普拉斯金字塔重构后,嵌入的信息对人眼不可见,并通过帧序列的形式播放重构图像,实现动态隐藏信息的发送。再次,在接收端,通过数码摄像机拍摄电子显示屏,在获得的帧图像中就包含发送的信息。由于拍摄到图像中包括电子显示屏的背景图案,所以需要通过图像分割技术,将目标图像从观测图像中分割出来。同时由于摄像机拍摄的角度与位置关系,得到的观测图像会存在几何失真,所以在提取信息前需要对图像进行几何校正。最后,将校正后的图像再进行拉普拉斯金字塔分解,从顶层子图像中提取出发送的信息。通过将提取信息与发送信息进行对比,证实该系统实现了信息的有效传递。
[Abstract]:Visual MIMO is a communication system which uses several light-emitting elements in a light-emitting array as an optical transmitter and a plurality of pixels on a digital camera image sensor as an optical receiver to generate multiple parallel channels and thus to realize a multi-input and multi-output communication system. It is similar to the MIMO idea of RF wireless communication, but it is very different in nature. Due to the high directivity of optical wave, the visual MIMO system can avoid cochannel interference and eavesdropping in RF communication. Because of the large field of view of the camera itself, compared with the traditional wireless optical communication, visual MIMO can also meet the needs of mobile communication, so it has great research significance and broad development space. In this paper, the technology of visual MIMO is used to realize the dynamic hidden information transmission. The information to be sent is embedded in the image of the electronic display screen so that it is invisible to the human eye. Information sent can be extracted. In this way, the communication function of the electronic display can be increased on the basis of not changing the original purpose of the electronic display, so that the electronic display has dual functions. This can greatly reduce the investment in communications equipment, reduce the cost. How to embed and extract dynamic hidden information is the main work of this paper. Firstly, according to the principle of visual MIMO technology, a simple computer display screen-digital camera communication system is established. The computer vision algorithms which need to be applied in digital image processing are introduced in detail, including multi-resolution analysis, feature detection and matching, image segmentation and image geometric correction. Secondly, at the sending end, the original image is divided into four sub-images by Laplacian pyramid decomposition, and the information to be sent is embedded into the top-level sub-image through multiplication operation. Because the top-level sub-image is low-frequency information, the human eye is not sensitive to it, so it can ensure that the embedded information is invisible to the human eye after the Laplacian pyramid reconstruction, and the reconstructed image is played through the form of frame sequence. Realize the sending of dynamic hidden information. Thirdly, at the receiving end, the electronic display screen is photographed by a digital camera, and the transmitted information is included in the obtained frame image. Because the background pattern of the electronic display screen is included in the image, it is necessary to segment the target image from the observation image by image segmentation technology. At the same time because of the relationship between the angle and the position of the camera the geometry distortion of the observed image will exist so the geometric correction of the image is needed before extracting the information. Finally, the corrected image is decomposed into Laplacian pyramid to extract the sent information from the top-level sub-image. By comparing the extracted information with the sending information, it is proved that the system realizes the effective transmission of information.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP391.41;TN919.3

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