Fast Image Matching Algorithm Research Articles

SIFT fast image matching algorithm with local adaptive threshold

SIFT fast image matching algorithm with local adaptive threshold

Research on image stitching method based on improved ORB and stitching line calculation

Image matching is one of the hot issues in recent years. Image matching determines the effect of image mosaic to a large extent. Therefore, a stable, accurate, and fast image matching algorithm is very important for the subsequent processing of image information. Most of the traditional image matching methods have the problems of high-error matching rate and difficulty in to eliminating false matching. To resolve the shortcomings listed here, an improved algorithm was proposed in which a combined measure of Hamming distance. Similarity measurement with Tanimoto similarity measurement was adopted to dispose binary feature vectors. In addition, as an important step in the process of image mosaics, the calculation of the best mosaics can eliminate the ghosting and ghosting that may appear in the mosaics. However, the traditional dynamic planning method is easy to pass through the obstacles and form obvious stitching traces when searching for stitching lines in images with large obstacles. In view of the aforementioned content, we propose a fast and robust method to search the image difference matrix and structure difference matrix of the overlapping area of the input image according to the search strategy to determine the pixel coordinates of the splicing line. Finally, from an optimal splicing line, the experimental results show that our algorithm performs well for eliminating error matching points. Compared with traditional algorithms, matching accuracy is improved by 25%. In terms of calculating the optimal splicing line, the method proposed is faster than the traditional method and has good robustness.

A fast RFID image matching algorithm for multi-tag identification and distribution optimization

We propose an improved image matching algorithm that combines the minimum feature value algorithm to extract feature points and the direction gradient histogram to calculate the description vector. This algorithm is oriented to RFID multi-tag identification and distribution optimization in the actual scenario, and the traditional SURF algorithm has the problems of low matching accuracy and high complexity in multi-tag matching. This algorithm effectively improves the positioning accuracy of the RFID multi-tag positioning system. The experimental results show that the matching success rate of the improved algorithm in this paper is 87.4%, which is 50% higher than the SURF algorithm. Not only the matching accuracy is greatly improved, but the running speed is also increased by 48%. The algorithm in this paper has high matching accuracy and real-time performance.It provides an effective way for RFID multi-tag real-time fast matching and precise positioning.

Fast Image-matching Technique Robust to Rotation in Spherical Images

There are many studies on 3D reconstruction using image-matching algorithms for 360-degree spherical images. However, it is difficult to apply conventional planar-based matching algorithms because a spherical image is represented in 3D space with a geodesic grid. In this study, a fast image-matching algorithm especially robust to rotation in spherical images is proposed. With interleaving and hashing techniques, memory waste is reduced and memory access efficiency is improved in mapping a 2D flatten icosahedron corresponding to a 3D icosphere. In addition, a modified Features from Accelerated Segment Test–based matching technique is proposed to improve robust matching performance. The proposed matching technique uses a descriptor with directional information order to endure rotation of images.

Fast image matching algorithm with approximate affine and scale invariance

Fast image matching algorithm with approximate affine and scale invariance

A fast matching algorithm for the images with large scale disparity

With the expansion of application areas of unmanned aerial vehicle (UAV) applications, there is a rising demand to realize UAV navigation by means of computer vision. Speeded-Up Robust Features (SURF) is an ideal image matching algorithm to be applied to solve the location for UAV. However, if there is a large scale difference between two images with the same scene taken by UAV and satellite respectively, it is difficult to apply SURF to complete the accurate image matching directly. In this paper, a fast image matching algorithm which can bridge the huge scale gap is proposed. The fast matching algorithm searches an optimal scaling ratio based on the ground distance represented by pixel. Meanwhile, a validity index for validating the performance of matching is given. The experimental results illustrate that the proposed algorithm performs better performance both on speed and accuracy. What's more, the proposed algorithm can also obtain the correct matching results on the images with rotation. Therefore, the proposed algorithm could be applied to location and navigation for UAV in future.

Fast image matching algorithm based on template partitioning and subtemplate matching

Matching algorithms based on pixel grey value are very popular and widely used in image matching. However, these algorithms have high time complexity and are sensitive to the size of image. To reduce the time complexity and sensitivity to the size of image of the matching algorithms based on pixel grey value, a fast image matching algorithm based on template partitioning and subtemplate matching is proposed. The algorithm divides the template into multiple subtemplates, then the eigenvalue of every subtemplate is calculated and the optimal one is chosen when the difference between the eigenvalues of the subtemplates and the subimage is minimum, and finally the best matching position for the reference image is determined by adopting non-ergodic search during image matching processing. The algorithm's time complexity is reduced to OS − N + 1² × N². Experimental results show that the proposed algorithm is superior to the circular projection algorithm and the NCC algorithm and has low computational complexity.

Fast image matching algorithm based on affine invariants

Feature-based image matching algorithms play an indispensable role in automatic target recognition (ATR). In this work, a fast image matching algorithm (FIMA) is proposed which utilizes the geometry feature of extended centroid (EC) to build affine invariants. Based on affine invariants of the length ratio of two parallel line segments, FIMA overcomes the invalidation problem of the state-of-the-art algorithms based on affine geometry features, and increases the feature diversity of different targets, thus reducing misjudgment rate during recognizing targets. However, it is found that FIMA suffers from the parallelogram contour problem and the coincidence invalidation. An advanced FIMA is designed to cope with these problems. Experiments prove that the proposed algorithms have better robustness for Gaussian noise, gray-scale change, contrast change, illumination and small three-dimensional rotation. Compared with the latest fast image matching algorithms based on geometry features, FIMA reaches the speedup of approximate 1.75 times. Thus, FIMA would be more suitable for actual ATR applications.

실시간 고정밀 영상 지오레퍼런싱을 위한 고속 연속 번들 조정 알고리즘

영상 기반의 정밀한 내비게이션이나 증강현실을 구현하기 위해서 고정밀 영상 지오레퍼런싱의 실시간 수행이 필수적이다. 일반적으로 고정밀 영상 지오레퍼런싱은 일괄 번들 조정 알고리즘을 적용하여 성취될 수 있으나 처리시간으로 인해 후처리로만 가능하였다. 최근에 제안된 연속 번들 조정 알고리즘은 이와 유사한 정확도의 결과를 고속으로 산출하여 실시간 처리의 가능성을 열었다. 그러나 처리시간이 영상의 개수에 따라 점진적으로 증가하기 때문에 영상이 아주 많은 경우에 실시간 수행이 보장되지 못하는 한계가 있었다. 이러한 연속 번들 조정 알고리즘을 보완하여 본 연구는 실시간 처리를 위해 영상의 개수와 무관하게 처리시간을 항상 일정 범위로 한정시킬 수 있는 알고리즘을 제안한다. 제안된 알고리즘은 기존의 영상들 중에서 새롭게 취득된 영상과 통계적으로 관련성이 높은 영상들만 고려하기 때문에 처리시간을 일정 범위로 한정시키면서도 비교적 정확한 결과를 산출할 수 있다. 제안된 알고리즘을 1Hz로 취득된 영상에 적용한 결과, 평균적으로 영상을 취득할 때마다 0.02 초 이내의 처리시간을 소요하면서 기존의 일괄 번들 조정 알고리즘의 결과와 비교하여 지상점 좌표를 기준으로 <TEX>${\pm}5$</TEX> cm 이내의 정확도로 지오레퍼런싱을 수행할 수 있었다. 신뢰성 높은 고속의 영상 매칭 알고리즘과 결합된다면 스마트폰 또는 UAV 등으로 동영상을 취득하면서 함께 탑재된 위치/자세 센서의 성능을 보완하여 고정밀의 실시간 지오레퍼런싱이 가능할 것으로 판단된다. Real-time high-precision image georeferencing is important for the realization of image based precise navigation or sophisticated augmented reality. In general, high-precision image georeferencing can be achieved using the conventional simultaneous bundle adjustment algorithm, which can be performed only as post-processing due to its processing time. The recently proposed sequential bundle adjustment algorithm can rapidly produce the results of the similar accuracy and thus opens a possibility of real-time processing. However, since the processing time still increases linearly according to the number of images, if the number of images are too large, its real-time processing is not guaranteed. Based on this algorithm, we propose a modified fast algorithm, the processing time of which is maintained within a limit regardless of the number of images. Since the proposed algorithm considers only the existing images of high correlation with the newly acquired image, it can not only maintain the processing time but also produce accurate results. We applied the proposed algorithm to the images acquired with 1Hz. It is found that the processing time is about 0.02 seconds at the acquisition time of each image in average and the accuracy is about <TEX>${\pm}5$</TEX> cm on the ground point coordinates in comparison with the results of the conventional simultaneous bundle adjustment algorithm. If this algorithm is converged with a fast image matching algorithm of high reliability, it enables high precision real-time georeferencing of the moving images acquired from a smartphone or UAV by complementing the performance of position and attitude sensors mounted together.

Fast image matching algorithm with area centroid

Fast image matching algorithm with area centroid

Fast high-precision reliable image matching algorithm based on shape

A shape-based matching algorithm was proposed to improve the accuracy and speed of image matching in industrial detection.It is the template matching based on shape information,using image pyramid strategy,according to matching similarity measures defined.Specific process was as follows: first,the template was generated by selecting the interest region in the reference image.Then,the template and the search image were filtered using Canny operator,and the direction vectors of their edges were computed.The image pyramids were constructed for the filtered template and the filtered search image on this basis.The image matching was carried out on the highest level of the image pyramids according to the similarity measures defined.After the potential matches with matching scores were identified,they were tracked through the resolution hierarchy according to scores descending in successive until they were found on the lowest level of the image pyramids.Finally,the sub-pixel precision pose parameters were achieved through the least-squares method.Experimental results demonstrate that the proposed algorithm has fast speed and high accuracy,moreover it is robust to the occlusion,clutter,nonlinear illumination,defocus,low contrast,global contrast change,local contrast change,and so on,which meets the actual industrial demand effectively.