关键词: 图像检索, 自适应中值滤波器, Sobel算子, 边缘方向直方图, 斯皮尔曼等级相关

Abstract: With regard to the advantages and disadvantages of image retrieval algorithm based on edge orientation autocorrelogram, a kind of image retrieval algorithm based on edge direction histogram correlation matching was proposed. Firstly, the salt and pepper noise in image was filtered by using an adaptive median filter, and then Sobel operator was used to extract image edge. After the edge orientation histogram was got through calculating the edge gradient amplitude and angle, the feature vector was constituted. Lastly, Spearman rank correlation coefficient was used to calculate the correlation coefficient between the feature vectors of images, as a measure of image similarity. Compared with the algorithm based on edge orientation autocorrelogram, the average precision and the recall rate of the new image retrieval algorithm increased by 10.5% and 9.7%. And the retrieval time consumption was also reduced by 7.5%. The experimental results verify the effectiveness of the proposed algorithm. The algorithm could be applied in medium to large image retrieval system to improve retrieval effect and raise the system speed.

Key words: image retrieval, adaptive median filter, Sobel operator, edge direction histogram, Spearman rank correlation