1、对图像边缘检测算法的研究学术报告 中英文翻译To image edge examination algorithm research academic report Abstract In image processing, as a basic characteristic, the edge of the image, which is widely used in the recognition, segmentation, intensification and compress of the image, is often applied to high-level domain.
2、There are many kinds of ways to detect the edge. In general, there are two main techniques: one is classic method based on the gray grade of every pixel; the other one is based on wavelet and its multi-scale characteristic. The first method, which is got the longest research, gets the edge according
3、 to the variety of the pixel gray. The main techniques are Robert, Laplace, Sobel, Canny and LOG algorithm. The second method, which is based on wavelet transform, utilizes the Lipschitz exponent characterization of the noise and singular signal and then achieves the goal of removing noise and disti
4、lling the real edge lines. In recent years, a new kind of detection method, which based on the phase information of the pixel, is developed. We need hypothesize nothing about images in advance. The edge is easy to find in frequency domain. Its a reliable method. In chapter one, we give an overview o
5、f the image edge. And in chapter two, some classic detection algorithms are introduced. The cause of positional error is analyzed, and then discussed a more precision method in edge orientation. In chapter three, wavelet theory is introduced. The detection methods based on sampling wavelet transform
6、, which can extract maim edge of the image effectively, and non-sampling wavelet transform, which can remain the optimum spatial information, are recommended respectively. In the last chapter of this thesis, the algorithm based on phase information is introduced. Using the log Gabor wavelet, two-dim
7、ension filter is constructed, many kinds of edges are detected, including Mach Band, which indicates it is a outstanding and bio-simulation method. Hoping all the work in this paper is of some value to research and applications of image edge detection. The image edge is one of image most basic chara
8、cteristics, often is carrying image majority of information. But the edge exists in the image irregular structure and in not the steady phenomenon, also namely exists in the signal point of discontinuity place, these spots have given the image outline position, these outlines are frequently we when
9、the imagery processing needs the extremely important some representative condition, this needs us to examine and to withdraw its edge to an image. But the edge examination algorithm is in the imagery processing question one of classical technical difficult problems, its solution carries on the high
10、level regarding us the characteristic description, the recognition and the understanding and so on has the significant influence; Also because the edge examination all has in many aspects the extremely important use value, therefore how the people are devoting continuously in study and solve the str
11、ucture to leave have the good nature and the good effect edge examination operator question. In the usual situation, we may the signal in singular point and the point of discontinuity thought is in the image peripheral point, its nearby gradation change situation may reflect from its neighboring pic
12、ture element gradation distribution gradient. According to this characteristic, we proposed many kinds of edge examination operator: If Robert operator, Sobel operator, Prewitt operator, Laplace operator and so on. These methods many are waiting for the processing picture element to carry on the gra
13、dation analysis for the central neighborhood achievement the foundation realized and has already obtained the good processing effect to the image edge extraction.But this kind of method simultaneously also exists has the edge picture element width, the noise jamming is serious and so on the shortcom
14、ings, even if uses some auxiliary methods to perform the noise removal, also corresponding can bring the flaw which the edge fuzzy and so on overcomes with difficulty. Along with the wavelet analysis appearance, its good time frequency partial characteristic by the widespread application in the imag
15、ery processing and in the pattern recognition domain, becomes in the signal processing the commonly used method and the powerful tool. Through the wavelet analysis, may interweave decomposes in the same place each kind of composite signal the different frequency the block signal, but carries on the
16、edge examination through the wavelet transformation, may use its multi-criteria and the multi-resolution nature fully , real effective expresses the image the edge characteristic. When the wavelet transformation criterion reduces, is more sensitive to the image detail; But when the criterion increas
17、es, the image detail is filtered out, the examination edge will be only the thick outline. This characteristic is extremely useful in the pattern recognition, we may be called this thick outline the image the main edge. If will be able an image main edge clear integrity extraction, this to the goal
18、division, the recognition and so on following processing to bring the enormous convenience. Generally speaking, the above method all is the work which does based on the image luminance information. In the multitudinous scientific research worker under, has obtained the very good effect diligently. B
19、ut, because the image edge receives physical condition and so on the illumination influences quite to be big above, often enables many to have a common shortcoming based on brightness edge detection method, that is the edge is not continual, does not seal up .Considered the phase information in the
20、image importance as well as its stable characteristic, causes using the phase information to carry on the imagery processing into new research topic. In this paper soon introduces one kind based on the phase image characteristic examination method - - phase uniform method. It is not uses the image t
21、he luminance information, but is its phase characteristic, namely supposition image Fourier component phase most consistent spot achievement characteristic point. Not only it can examine brightness characteristics and so on step characteristic, line characteristic, moreover can examine Mach belt phe
22、nomenon which produces as a result of the human vision sensation characteristic. Because the phase uniformity does not need to carry on any supposition to the image characteristic type, therefore it has the very strong versatility. The image majority main information all exists in the image edge, th
23、e main performance for the image partial characteristic discontinuity, is in the image the gradation change quite fierce place, also is the signal which we usually said has the strange change place. The strange signal the gradation change which moves towards along the edge is fierce, usually we divi
24、de the edge for the step shape and the roof shape two kind of types. In the step edge two side grey levels have the obvious change; But the roof shape edge is located the gradation increase and the reduced intersection point. May portray the peripheral point in mathematics using the gradation deriva
25、tive the change, to the step edge, the roof shape edge asks its step, the second time derivative separately. To an edge, has the possibility simultaneously to have the step and the line edge characteristic. For example on a surface, changes from a plane to the normal direction different another plan
26、e can produce the step edge; If this surface has the edges and corners which the regular reflection characteristic also two planes form quite to be smooth, then works as when edges and corners smooth surface normal after mirror surface reflection angle, as a result of the regular reflection componen
27、t, can produce the bright light strip on the edges and corners smooth surface, such edge looked like has likely superimposed a line edge in the step edge. Because edge possible and in scene object important characteristic correspondence, therefore it is the very important image characteristic. For i
28、nstance, an object outline usually produces the step edge, because the object image intensity is different with the background image intensity. The paper selected topic originates in holds the important status and the function practical application topic in the image project. The so-called image pro
29、ject discipline is refers foundation discipline and so on mathematics, optics principles, the discipline which in the image application unifies which accumulates the technical background develops. The image projects content are extremely rich, and so on divides into three levels differently accordin
30、g to the abstract degree and the research technique: Imagery processing, image analysis and image understanding. The image division is in between the image analysis and the imagery processing, its meaning is, the image division is from the imagery processing to the image analysis essential step, als
31、o is further understands the image the foundation. The image division has the important influence to the characteristic. The image division and based on the division goal expression, the characteristic extraction and the parameter survey and so on transforms the primitive image as a more abstract mo
32、re compact form, causes the high-level image analysis and possibly understands into. But the edge examination is the image division core content; therefore the edge examination holds the important status and the function in the image project. Therefore the edge examination research always is in the
33、image engineering research the hot spot and the focal point, moreover the people enhance unceasingly to its attention and the investment. We knew that, the edge examination essence is uses some algorithm to withdraw in the image the object and the background junction demarcation line. We define the edge for the image in the gradation occur the rapid change region boundary. The image g
