Search results for "Mosaicing"

Super-resolution-based magnification of endothelium cells from biomicroscope videos of the cornea

2018

We present a practical, robust, and effective pipeline to compute a high-resolution (HR) image of the corneal endothelium starting from a low-resolution (LR) video sequence obtained with a general purpose slit lamp biomicroscope. An image quality typical of dedicated and more expensive confocal microscopes is achieved via software magnification by exploiting information redundancy in the video sequence. In particular, the HR image is generated from the best LR frames, obtained by identifying the most suitable endothelium video subsequence using a support vector machine-based learning approach, followed by a robust graph-based frame registration. Results on long, real sequences show that the…

Color Correction for Image Stitching by Monotone Cubic Spline Interpolation

2015

This paper proposes a novel color correction scheme for image stitching where the color map transfer is modelled by a monotone Hermite cubic spline and smoothly propagated into the target image. A three-segments monotone cubic spline minimizing color distribution statistics and gradient differences with respect to both the source and target images is used. While the spline model can handle non-linear color maps, the minimization over the gradient differences limits strong alterations on the image structure. Adaptive heuristics are introduced to reduce the minimization search space and thus computational time. Experimental comparisons with respect to the state-of-the-art linear mapping model…

Dealing with reconstruction problems: two cases study

Reconstruction problems are always included in a computer vision system as one of the key step toward the recognition of a scene. There are hierarchies of reconstruction that go from pixels to regions in the lower level, and from patches to objects in higher steps. The success of the reconstruction phase de-pends on several factors: the selection of "suitable" features, the matching function, the linking strategy. I this paper we show some of problems and solutions in two different contexts: the 3D reconstruction from cloud of points representing fragments of archeological finding, and the mosaicing from sea bed video frames. Preliminary results show that in both cases the accuracy is satis…

Global Archaelogical Mosaicing for Underwater Scenes

2006

This contribution regards the mosaicing of seabed landscapes, in order to represent higher resolution photos of whole sites with wrecks in a fast and safe fashion. A stereo vision system has been arranged by adding two cameras to the payload aboard a Remotely Operated Vehicle. A number of problems arise due to poor luminosity, cloudy water, water distortion and presence of artifacts. A robust algorithm has been defined to reduce the radial distortion of the camera lenses and to enhance the results.

eISP: a Programmable Processing Architecture for Smart Phone Image Enhancement

2009

4 pages; Today's smart phones, with their embedded high-resolution video sensors, require computing capacities that are too high to easily meet stringent silicon area and power consumption requirements (some one and a half square millimeters and half a watt) especially when programmable components are used. To develop such capacities, integrators still rely on dedicated low resolution video processing components, whose drawback is low flexibility. With this in mind, our paper presents eISP {--} a new, fully programmable Embedded Image Signal Processor architecture, now validated in {TSMC 65nm} technology to achieve a capacity of {16.8 GOPs} at {233 MHz}, for {1.5 mm$^2$} of silicon area and…

Characterization of a digital camera as an absolute tristimulus colorimeter

2003

An algorithm is proposed for the spectral and colorimetric characterization of digital still cameras (DSC) which allows them to be used as tele-colorimeters with CIE-XYZ color output, in cd/m2. The spectral characterization consists in the calculation of the color-matching functions from the previously measured spectral sensitivities. The colorimetric characterization consists in trans- forming the raw RGB digital data into absolute tristimulus values CIE-XYZ (in cd/m2) under variable and unknown spectroradiometric conditions. Thus, in the first stage, a gray balance was applied over the raw RGB digital data to convert them into RGB relative colorimetric values. In the second stage, an algo…

HDR Imaging Pipeline for Spectral Filter Array Cameras

2017

Multispectral single shot imaging systems can benefit computer vision applications in needs of a compact and affordable imaging system. Spectral filter arrays technology meets the requirement, but can lead to artifacts due to inhomogeneous intensity levels between spectral channels due to filter manufacturing constraints, illumination and object properties. One solution to solve this problem is to use high dynamic range imaging techniques on these sensors. We define a spectral imaging pipeline that incorporates high dynamic range, demosaicing and color image visualization. Qualitative evaluation is based on real images captured with a prototype of spectral filter array sensor in the visible…

Underwater archaeological mosaicing

2006

Archaeological mosaicing is one of the challenges of the computer vision community and it can be faced in a 2D or 3D approach. This contribution regards a methodology to do a mosaic of an underwater bi-dimensional scene. A number of problems arise from the acquisition of images by a remote operated vehicle. Radial distortion, poor luminosity, cloud water, presence of artefacts are part of the issues that can occur; for instance, the radial distortion has been corrected to improve the quality of the input images. Keypoints detection (through SIFT transform), Singular Value Decomposition, Random Samples Consensus are some of the techniques applied in our method. This contribution regards the …

Sensors based on MultiSpectral Filter Arrays

2014

International audience; Spectral Filter arrays (SFA) is an emerging technology for multispectral image acquisition. SFAs make possible the use of a compact multispectral sensor to acquire still images or video. One part of this talk will present and compare typical multispectral and color image acquisition systems in order to clearly identify differences underlying SFA technologies. The other part of this talk will show the difficulties and advances that we have made at the University of Bourgogne in the building of such sensors from the design of filters to data processing, such as demosaicing.