A simple and effective automatic focusing algorithm is proposed in this article. The principle of the proposed automatic focusing algorithm is based on that, for the radial test pattern, a best-focused image should have the smallest blurred region in the middle of the acquired image, and hence, should have the smallest equivalent radius. The circular Hough transform has became a common method i...

For more than half a century, the Hough transform is everexpanding for new frontiers. Thousands of research papers and numerous applications have evolved over the decades. Carrying out an all-inclusive survey is hardly possible and enormously space-demanding. What we care about here is emphasizing some of the most crucial milestones of the transform. We describe its variations elaborating on th...

method gives satisfactory results. Finding peaks is a more difficult task in the radius histogram in the two-stage This paper presents a circle-finding method to deal with partially occluded circles using segmented contours. Contours Hough transform [3, 4], which is sensitive to inaccuracy in are segmented using a criterion based on the derivative of the the first stage. A particular deficiency...

Robust person detection in real-world images is interesting and important for a variety of applications, such as visual surveillance. We address the task of detecting persons in elevator surveillance scenes in this paper. To get more passengers in the lift car, the camera usually installed at the corner of ceiling. However, the high and space of lift car are limited, which makes person occluded...

Objects can be identified in images extracting local image descriptors for interesting regions. In this paper, instead of making the handle identification process rely in the keypoint detection/matching process only, we present a method that first extracts from the image a region of interest (ROI) that with high probability contains the handle. This subimage is then processed by the keypoint de...

In this paper, we present a machine vision approach for detecting and inspecting circular parts and the parts with circular arcs on the contours. The method uses the Hough transform technique and utilizes the directional information of a normal to the circle at each boundary point. A cubic polynomial curve fitting is used to estimate the normal and determine the concavity of the fitted curve at...

a r t i c l e i n f o a b s t r a c t Commercial iris recognition systems do not perform well for non-ideal data, because their iris localization algorithms are specifically developed for controlled data. This paper presents a robust iris localization algorithm for less constrained data. It includes: (i) suppressing specular reflections; (ii) localizing the iris inner (pupil circle) and outer (...