There is a growing trend to use a digital camera as an instrument to measure velocity instead of a regular sensor approach. This paper introduces a new proposal for estimating kinematic quantities, namely, the angle and the relative speed, from a single motion blur image using the discrete cosine transform (DCT). Motion blur is a common phenomenon present in images due to the relative movement between the camera and the objects, during sensor exposure to light. Today, this source of kinematic data is mostly dismissed. The introduced technique focuses on cases where the camera moves at a constant linear velocity while the background remains unchanged. 2250 motion blur pictures were shot for the angle experiments and 500 for the speed estimation experiments, in a light and distance controlled environment, using a belt motor slider driven at angles between 0° and 90° and 10 preset speeds. The DCT Hough and DCT Radon results were compared to discrete Fourier transform (DFT) Hough and DFT Radon algorithms for angle estimation. The mean absolute error of the DCT Radon method for direction estimation was 4.66°. In addition, the mean relative error for speed estimation of the DCT Pseudocepstrum was 5.15%. The innovative DCT frequency analysis proposals were more accurate than all competitors evaluated for the reconstruction of the point spread function that enables calculation of relative velocity and motion direction. These results demonstrate that cameras as an instrument can be used to measure velocity even using a single linear motion blur degraded image.

A Monte Carlo simulation study of the exchange bias properties in ferromagnetic/antiferromagnetic (FM/AFM) bilayers by using a classical Heisenberg model and the Metropolis algorithm is addressed. In our model several contributions including nearest neighbors exchange interactions, two different interface couplings, magnetocrystalline anisotropy, and a Zeeman term were considered. Our study focuses on the influence of FM and AFM layer thicknesses (dF and dA ) on hysteresis loops, particularly exchange bias field (H_EB) and coercive force (H_c) . Results reveal that the influence of dA on the exchange bias phenomenon is negligible, while dF produces an important effect on H_EB and H_c. Such behaviors agree with several models and results reported in the literature. Concretely, our model allows inferring a dependence of the exchange bias field with the FM layer thickness proportional to 1/(dF)m characterized by an exponent m = 0.71plusmn0.11. On the other hand, coercive force exhibits a power law increase with the FM layer thickness when thermal fluctuations become relevant. For completeness, thermal stability of the hysteretic properties is finally presented and discussed.

A methodology for segmentation and extraction morphologic feature from nailfold capillaroscopic images is presented. The main characteristic of the images studied here is the low contrast between the background and the capillaries.For this reason, three fundamental steps were applied in the preprocess: correction of the illumination, highlight and smoothing. For segmenting these images, Laplacians of the most contrasted component in each color space and the connectedness by threshold (region growth) were integrated. The extraction was carried out using image processing techniques such as principal components analysis (PCA), fractal geometry and tortuosity index (TI); their properties were proven. Tortuosity index is a clinical variable subjective to the expert, it is presented as the ratio between the area and the fractal dimension (FD) of the capillary region. Other features obtained were width and height, density of capillaries, area and perimeter, orientation and polarity. The work was carried out on 300 capillaries obtained from images of subjects that do not suffer vascular diseases of the connective tissues and 250 capillaries of patients that have Lupus erythematosus (SLE). Images were taken from the third and fourth fingers of both subjectpsilas hands. The application of the automatic segmentation allowed the classification of the capillary tortuosity and the comparison to the manual segmentation which was made on 47 capillary images by an expert in dermatology.