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Conclusions and Perspectives

In this thesis, we have addressed on the applications of cellular neural networks (CNN’s) in high-order image processing. We start with introducing the fundamentals and design guidelines of CNN and GA to deduce the later architecture that we proposed in this thesis. For using CNN’s in some specific image application, we use genetic algorithm (GA) to optimize a better CNN template. The major reason that we used GA as an analytical training tool for our issuing problems lies in the prevailing applied field and evolution mechanism of GA. As we know, search of CNN templates could be sometimes too complicated to follow the rules in higher-order image processing. Thus, we introduced some basic but significant CNN template examples at the first place so as to inspire more applications based on CNN’s by observing the nature of images. Most significantly, we make use of CNN’s to deal with some difficult issues of image processing, image descreening in particular, which has been regarded as a tough question since no single solution can be applied to all cases.

However in this thesis, we classify the original screening images in two classes beforehand by our defined index, and a different simple filter would be applied to each of these two classes. In this application, CNN plays an important role in classification of images by looking upon screening patterns as different textures. The descreened images hence could be more satisfactory and acceptable to human perception.

What’s more, we focus on texture discrimination and representation for more image applications related to texture analysis. In this aspect, we proposed a brand-new structure to proliferate CNN templates, which makes decision of CNN templates more flexible. We do not have to assume how many templates to be optimized at the beginning of texture classification, and instead we adaptively determine the number of

optimized templates for the characteristics of the texture set. CNN can be no doubt used here on account of its filtering capability and attraction of hardware implementability. To characterized CNN more sensitively in various kinds of texture patterns, we also presented a series of features, Transition Bit String (TBS) defined in this thesis, for more practical uses. Also, our feature series could not be necessarily carried out by CNN. To be more organized, we have the following major contributions in this thesis.

A. We propose a systematical method for image descreening.

B. We inspire an idea of screening pattern classification in advance for image descreening, which makes image documentation simpler and more impressive.

C. We present a proliferation structure to determine CNN templates in a more flexible fashion.

D. We innovate a kind of characterizing features for texture analysis.

E. We give more possibilities of hardware implementations in high-order image processing.

To sum up, this thesis not only provides an approach in the recent state-of-the-art but also gives more chances and perspectives for hardware implemented in high-order image applications. In addition, the indices and features proposed in this thesis would bring about more solutions in the complicated problems of image processing. We shall at this place list some researching fields that might be carried out in the future.

A. Hardware implementation

The main content of this thesis would like to apply the CNN structure to more applications in pursuit of future hardware implementation or chip design.

Therefore, this future work might be the most important and ultimate issue among many kinds of applications inspired by this thesis.

B. Augment of more CNN channels

CNN used to apply to applications of image processing only in gray-scale, which might cause the loss of some important information of original images. It is certainly believed that more channels of CNN implementation could do a great help for some specific applications of images that should depend on the color information of original images. So the implementation of more CNN channels might provide more solutions for more complicated problems of image processing.

C. Feature selection of CNN proliferation structure

In this thesis, we only take into consideration the generative way of extracted features for our CNN proliferation structure due to the augmented properties of TBS feature series. Of course, for the concept of feature selection, how to reduce the number of features might also be useful in pattern recognition. The consideration of how to select useful features could be put forth in the future.

D. More applications or generalization of TBS

We have presented the basic definition and formula of TBS in this thesis, and TBS series have also been proven to be useful in representation of various texture patterns. As what we have concluded earlier, TBS series would not necessarily be applied to CNN outputs, and these feature curves could be quite useful for analyzing image data in software-oriented applications. More specifically, TBS series could be expressed in various cases of requirements of images. For example, the setting of threshold, the scanning directions, the way of counting pixels, and so on would provide more flexible tuning parameters for more versatile image applications.

E. More applications of image processing by CNN

No doubt, more applications of image processing are the major goals that this

thesis pursues. This thesis has offered more way of using CNN output and illustrated the relationship between CNN structure and image data. It is observed that the results convolved from CNN outputs could also be expressed in terms of various sorts of definitions for images. More complicated applications of image processing could be consequently carried out in the future by our proposed feature series as well as the constructed structure.

In this section, we have concluded the major contributions and the possible future works in details. Hence, we would be dedicated to solving more and more issues of digital image processing by our proposed strategies using CNN in the future.

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