Search results for "Gaussian blur"
showing 3 items of 3 documents
Optimal Filter Estimation for Lucas-Kanade Optical Flow
2012
Optical flow algorithms offer a way to estimate motion from a sequence of images. The computation of optical flow plays a key-role in several computer vision applications, including motion detection and segmentation, frame interpolation, three-dimensional scene reconstruction, robot navigation and video compression. In the case of gradient based optical flow implementation, the pre-filtering step plays a vital role, not only for accurate computation of optical flow, but also for the improvement of performance. Generally, in optical flow computation, filtering is used at the initial level on original input images and afterwards, the images are resized. In this paper, we propose an image filt…
A blind Robust Image Watermarking Approach exploiting the DFT Magnitude
2019
Due to the current progress in Internet, digital contents (video, audio and images) are widely used. Distribution of multimedia contents is now faster and it allows for easy unauthorized reproduction of information. Digital watermarking came up while trying to solve this problem. Its main idea is to embed a watermark into a host digital content without affecting its quality. Moreover, watermarking can be used in several applications such as authentication, copy control, indexation, Copyright protection, etc. In this paper, we propose a blind robust image watermarking approach as a solution to the problem of copyright protection of digital images. The underlying concept of our method is to a…
Effect of Cycloplegia on Blur Perception Thresholds as Measured by Source Method
2017
Abstract One of the advantages of a source method over observer method in blur perception measurements is better control of a stimulus blur level, which is achieved with computerised image processing unlike the observer method that requires optical defocusing of the observer. The aim of this study was to determine if paralysation of accommodation has effect on blur perception thresholds, thereby evaluating its necessity in such experiments. Blur perception thresholds (just noticeable blur, clear image, recognition, and non-resolvable blur thresholds) were evaluated with (using cycloplegia) and without paralysed accommodation to determine effect on blur perception. A computerised low-pass sp…