Detecting Repetitive Patterns on Fabrics by Hough Transform

• Main Authors: Tsai,Tsung-Lin, 蔡宗霖
• Other Authors: Lin,Cheng-Chung
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/52811667233040192552

碩士 === 國立交通大學 === 多媒體工程研究所 === 103 === Perception of repetitive imagery patterns is a common experience to all in daily life, the detection of which is useful to many image-oriented applications, and as a result is chosen as the subject of this thesis. It is noted that, in an edge-featured map derived from an image with contents of repetitive patterns, the fragments of edges associated with repetitive-patterned areas appear to lie on the same “line”, which seems to be a general phenomenon through the examination on images in large amounts. Based on such observations, a pilot system exploiting Hough transform for identifying those fragments of edges through which a common line may pass is established. The system operates in 5 steps as follows: [1] Four edge-featured maps are derived from the input, each being with edges in specific orientation: 0゜, 90゜, 45゜, and 135゜. [2] The four maps are transformed into Hough-space, where thresh-holding is taken to select well-responded areas. The transformation is devised in such a way that every image entity in Hough-space is associated with (x, y) coordinates of its counterpart in the image-space. [3] Inverse transform the 4 Hough-space maps back to 4 maps in image-space, in which all in-line fragments are respectively recovered. [4] Clustering of in-line fragments in each of the 4 image-space maps is conducted, where a weighting process is devised so that regions of potential targets may be discerned from uninterested ones via k-mean clustering. [5] A final fusing of the 4 maps of in-lined oriented-fragments, where process of congregating mutual supportive/antagonistic information among 4 maps is performed, concludes the entire process. Initial experiment on a set of images shows encouraging results from the system when extracting repetitive-patterned dresses/fashion where in-lined fragments are relatively close to one another in testing images. As for images of buildings, it is found that refinement of weighting process in [4] is needed for the cases where in-lined fragments appear to be not so tightly located, as shown in such regular architectural structures as window frames and column-and-beam, etc..