Super-resolution is a process that combines information from some low-resolution images in order to produce an image with higher resolution. In most of the previous related work, the blurriness that is associated with low resolution images is assumed to be due to the integral effect of the acquisition device’ s image sensor. However, in practice there are other sources of blurriness as well, including atmospheric and motion blur that may be applied to low resolution images. The research done in this paper provides a super-resolution image from some low-resolution images suffering from blurriness due to DEFOCUS. In contrast to motion blur kernels that are sparse, the DEFOCUS blur kernel is non-sparse and continuous. Because of the continuity property of DEFOCUS blurring kernel, in this paper, we bound the gradient of blurring kernel using proper regularizers to satisfy this property. Experimental results on synthetic data demonstrate the effectiveness of the proposed method to produce high resolution and de-blurred images from some blurry low-resolution images.

A conventional camera with small size pixels may capture images with DEFOCUSed blurred regions. Blurring, as a low-pass filter, attenuates or drops details of the captured image. This fact makes deblurring as an ill-posed problem. Coded aperture photography can decrease destructive effects of blurring in DEFOCUSed images. Hence, in this case, aperture patterns are designed or evaluated based on the manner of reduction of these effects. In this paper, a new function is presented that is applied for evaluating the aperture patterns which are designed for DEFOCUS deblurring. The proposed function consists of a weighted sum of two new criteria, which are defined based on spectral characteristics of an aperture pattern. On the basis of these criteria, a pattern whose spectral properties are more similar to a flat all-pass filter is assessed as a better pattern. The weights of these criteria are determined by a learning approach. An aggregate image quality assessment measure, including an existing perceptual metric and an objective metric, is used for determining the weights. According to the proposed evaluation function, a genetic algorithm that converges to a near-optimal binary aperture pattern is developed. In consequence, an asymmetric and a semi-symmetric pattern are proposed. The resulting patterns are compared with the circular aperture and some other patterns in different scenarios.

Background and Objectives: Depth from DEFOCUS and DEFOCUS deblurring from a single image are two challenging problems caused by the finite depth of field in conventional cameras. Coded aperture imaging is a branch of computational imaging, which is used to overcome these two problems. Up to now, different methods have been proposed for improving the results of either DEFOCUS deblurring or depth estimation. In this paper, an asymmetric coded aperture is proposed which improves results of depth estimation and DEFOCUS deblurring from a single input image.Methods: To this aim, a multi-objective optimization function taking into consideration both deblurring results and depth discrimination ability is proposed. Since aperture throughput affects on image quality, our optimization function is defined based on illumination conditions and camera specifications which yields an optimized throughput aperture. Because the designed pattern is asymmetric, DEFOCUSed objects on two sides of the focal plane can be distinguished. Depth estimation is performed using a new algorithm, which is based on perceptual image quality assessment criteria and can discern blurred objects lying in front or behind the focal plane.Results: Extensive simulations as well as experiments on a variety of real scenes are conducted to compare the performance of our aperture with previously proposed ones.Conclusion: Our aperture has been designed for indoor illumination settings. However, the proposed method can be utilized for designing and evaluating appropriate aperture patterns for different imaging conditions.

Purpose: To investigate the changes in higher-order aberrations (HOAs) induced by the implantation of implantable collamer lenses (ICLs) and Toric ICL (TICL) in eyes with high myopia and high myopic astigmatism. Methods: We investigated 33 eyes of 18 consecutive patients (in a prospective, interventional case series study), with spherical equivalent errors of
6. 00 to
21. 09 diopters (D) and cylindrical errors of
0. 5 to
4. 75 D, who underwent ICL and TICL implantation. Before and after 5 days, 2 and 6 months of surgery, the uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), DEFOCUS and adverse events of the surgery were assessed. Ocular HOAs were also evaluated by Hartmann-Shack aberrometry (Technolas PV, Rochester, New York, USA) before and after 6 months of surgery. Results: At 6. 0 months after surgery, the UCVA and BCVA in 40% and 66. 7% of eyes were 20/20, respectively. Mean DEFOCUS refraction and astigmatism was reduced to
0. 66 and 0. 65 D from
12. 79 and 2. 18 at baseline, respectively. For a 6 mm pupil, HOAs were not significantly changed, merely from 0. 417 ± 0. 162 m before surgery to 0. 393 ± 0. 119 m after surgery (P ¼ 0. 45). Spherical aberration (Z400) increased significantly (P ¼ 00. 0). Surgical induced astigmatism was lower than 0. 25 D, and there were no changes in trefoils and coma aberration. No vision-threatening complications occurred during the observation period. Conclusion: This study shows that the ICL and TICL performed well in correcting high myopic astigmatism without significant changes in HOAs during a 6-month observation period, although the spherical aberration (Z400) increased significantly.

Purpose: To evaluate the effect of asphericity and blue light filter (BLF) of three different intraocular lenses (IOLs) on the visual performance, second-and third-order aberrations (DEFOCUS, coma, trefoil), and contrast sensitivity after uneventful cataract surgery. Methods: One hundred and twenty eyes of 60 patients with clinically significant cataract were randomly assigned to receive one of the three IOL types: Bioline Yellow Accurate (aspheric, with BLF, i-medical, Germany), BioAcryl 60125 (spherical, without BLF, Biotech, France), and H65C/N (aspheric, without BLF, PhysIOL, Belgium). Each IOL was implanted in 40 eyes. Complete ophthalmologic examination, functional acuity contrast testing and wavefront analysis were performed 60 days postoperatively. Results: The mean postoperative best-corrected visual acuity (BCVA) was 0. 95 ± 0. 08, not differing statistically among the IOL groups (P = 0. 83). Mean DEFOCUS and coma values did not yield any statistically significant difference through the IOL groups varying from – 0. 784 to – 0. 614 μ m and 0. 129 to 0. 198 μ m (P = 0. 79 and 0. 34, respectively). Bioline Yellow Accurate IOL presented less trefoil aberrations, 0. 108 ± 0. 05 μ m, compared to the other two IOL types (BioAcryl [0. 206 ± 0. 19 μ m] and Physiol [0. 193 ± 0. 17 μ m], P < 0. 05). Contrast sensitivity values did not differ among the groups under all lighting conditions. Bioline Yellow IOL showed a statistically higher loss of contrast sensitivity (between mesopic and mesopic with glare conditions) compared to the BioAcryl and PhysIOL in 12 and 3 cpd spatial frequencies, respectively (P < 0. 05). Conclusion: Bioline Yellow IOL indicated lower contrast sensitivity under mesopic conditions when glare was applied but resulted in less trefoil aberrations after uneventful cataract surgery. No further differences were noted in postoperative visual performance among three IOL groups.