BACKGROUND In computed tomography (CT), there is increasing concern for potential CT radiation hazards. Several raw-data-based iterative reconstruction techniques attempt to facilitate low-dose imaging without compromising image quality, which raises the question whether these techniques may allow further dose reduction. PURPOSE To compare image quality of iterative reconstruction and filtere...

Diabetic retinopathy lesion detection such as exudate in fundus image of retina can lead to early diagnosis of the disease. Retinal image includes dark areas such as main blood vessels and retinal tissue and also bright areas such as optic disk, optical fibers and lesions e.g. exudate. In this paper, a multistage algorithm for the detection of exudate in foreground is proposed. The algorithm se...

With the development of compressive sensing theory, image reconstruction from few-view projections has received considerable research attentions in the field of computed tomography (CT). Total-variation- (TV-) based CT image reconstruction has been shown to be experimentally capable of producing accurate reconstructions from sparse-view data. In this study, a distributed reconstruction algorith...

The Image reconstruction is an important problem in optical tomography. The process of the image processing requires the study of photon migration in biological tissue. There are several approaches to study and simulate propagation of photons in biological tissues. These approaches are categorized into stochastic and analytical groups. The Monte Carlo method as a stochastic method is widely use...

Introduction: Iterative reconstruction techniques provide better image quality and have the potential for reconstructions with lower imaging dose than classical methods in computed tomography (CT). However, the computational speed is major concern for these iterative techniques. The system matrix calculation during the forward- and back projection is one of the most time- cons...

Information loss may occur frequently in the imaging of living tissues by using two-photon fluorescence microscopy due to the intensive deformation of the tissue. A landmark-based optical flow interpolation scheme is proposed for image reconstruction of living aorta walls in two-photon autofluorescence image sequences. Landmarks are extracted and evaluated by an active contour-based aorta model...

The goal of the presented experiments is the development of new optical tracking techniques for space objects, namely space debris, based on simultaneous CCD and laser measurements: the CCD tracking of a laser illuminated object, the simultaneous CCD tracking and laser ranging and the laser time-tagging of the CCD tracking. The first two experiments can be performed on cooperative corner retro-...

Satellite cameras are calibrated before launch in detail and in general, but it cannot be guaranteed that the geometry is not changing during launch and caused by thermal influences and drying out effects in the orbit. Modern satellite imaging systems are based on CCD-line sensors. Because of the required high sampling rate, the length of used CCD-lines is limited. For reaching a sufficient swa...

We show the feasibility of imaging objects having different optical scattering coefficients relative to the surrounding scattering medium using ultrasound-modulated optical tomography (UOT). While the spatial resolution depends on ultrasound parameters, the image contrast depends on the difference in scattering coefficient between the object and the surrounding medium. Experimental measurements...

C-arm cone-beam CT offers great potential in image-guided interventions, but conventional analytic reconstruction methods are associated with limited image quality, particularly for soft-tissue imaging. While model-based iterative reconstruction (IR) methods improve image quality and/or reduce radiation dose, long reconstruction time limits utility in clinical workflow. Additionally, in contras...