Weakly Supervised Multimodal Kernel for Categorizing Aerial Photographs.

Accurately distinguishing aerial photographs from different categories is a promising technique in computer vision. It can facilitate a series of applications, such as video surveillance and vehicle navigation. In this paper, a new image kernel is proposed for effectively recognizing aerial photographs. The key is to encode high-level semantic cues into local image patches in a weakly supervised way, and integrate multimodal visual features using a newly developed hashing algorithm. The flowchart can be elaborated as follows. Given an aerial photo, we first extract a number of graphlets to describe its topological structure. For each graphlet, we utilize color and texture to capture its appearance, and a weakly supervised algorithm to capture its semantics. Thereafter, aerial photo categorization can be naturally formulated as graphlet-to-graphlet matching. As the number of graphlets from each aerial photo is huge, to accelerate matching, we present a hashing algorithm to seamlessly fuze the multiple visual features into binary codes. Finally, an image kernel is calculated by fast matching the binary codes corresponding to each graphlet. And a multi-class SVM is learned for aerial photo categorization. We demonstrate the advantage of our proposed model by comparing it with state-of-the-art image descriptors. Moreover, an in-depth study of the descriptiveness of the hash-based graphlet is presented.

Perceptually Guided Photo Retargeting.

We propose perceptually guided photo retargeting, which shrinks a photo by simulating a human's process of sequentially perceiving visually/semantically important regions in a photo. In particular, we first project the local features (graphlets in this paper) onto a semantic space, wherein visual cues such as global spatial layout and rough geometric context are exploited. Thereafter, a sparsity-constrained learning algorithm is derived to select semantically representative graphlets of a photo, and the selecting process can be interpreted by a path which simulates how a human actively perceives semantics in a photo. Furthermore, we learn the prior distribution of such active graphlet paths (AGPs) from training photos that are marked as esthetically pleasing by multiple users. The learned priors enforce the corresponding AGP of a retargeted photo to be maximally similar to those from the training photos. On top of the retargeting model, we further design an online learning scheme to incrementally update the model with new photos that are esthetically pleasing. The online update module makes the algorithm less dependent on the number and contents of the initial training data. Experimental results show that: 1) the proposed AGP is over 90% consistent with human gaze shifting path, as verified by the eye-tracking data, and 2) the retargeting algorithm outperforms its competitors significantly, as AGP is more indicative of photo esthetics than conventional saliency maps.

Clinical comparison between brachytherapy of 0.5 ％ loteprednol etabonate eye drops and long-term therapy of 0.1％ fluorometholone eye drops after LASEK / 中华实验眼科杂志

Background Conventional corticosteroid therapy after laser epithelial keratomileusis (LASEK) is topical application of 0.1％ fluorometholone eye drops for 4 months,but this therapy increases the ocular hypertension risk and leads to poor compliance in patients.It is necessary to explore a safe and effective brachytherapeutic drug.Objective This study was to compare the clinical outcomes between the brachytherapy of 0.5％ loteprednol etabonate eye drops and the long-term therapy of 0.1％ fluorometholone eye drops after LASEK.Methods Clinical data were retrospectively analyzed from 208 right eyes in 208 mild and moderate myopia patients who received LASEK at Peking University Third Hospital from 2009 to 2013.The eye drops of 0.5％ loteprednol etabonate was used 6 times daily since operation day until postoperative day 5,and 4 times daily for a week,and then tapered for three consecutive weeks in 104 eyes of the loteprednol group after LASEK,and 0.1％ fluorometholone eye drops was applied topically 4 times daily for initial one month and then tapered for three consecutive months in another 104 eyes in the fluorometholone group after LASEK.Corneal epithelial healing time was compared between the two groups by recording the wearing duration of corneal contact lens.Noncontact intraocular pressure (lOP) was detected and corrected 5 days,2 weeks,1 month and 3,6 months after LASEK.Haze was scored based on the criteria of Cheng under the slit lamp microscope and apparently optometry was performed 1 month and 3,6 months after LASEK.Results The number of eyes removed corneal contact lens in 5,6 and 7 days after LASEK was not significantly different between the loteprednol group and the fluorometholone group (x2 =1.180,P =0.554).No considerable differences were seen in the eye numbers with the equivalent spherical lens (absolute value) ≤0.5 D in 1 month,3months and 6 months after LASEK (Z=-1.028,P=0.304;Z=-0.398,P=0.691;Z=-0.445,P=0.656).In the fifth days after surgery,the median corrected IOP was 13.52 mmHg and 13.12 mmHg in the loteprednol group and the fluorometholone group,respectively,showing a significant difference between them (Z =-1.985,P =0.047),but no significant differences were found in IOP in 2 weeks,1 month and 3 months,6 months after surgery between the two groups (all at P＞0.05).IOP elevated (postoperative IOP-preoperative IOP ≥ 5 mmHg) after LASEK in 5 eyes in the loteprednol group and 4 eyes in the fluorometholone group (x2 =0.116,P =0.733).In 1 month after surgery,the number of eyes in different grades of haze was significantly decreased in the loteprednol group compared with the fluorometholone group (x2=13.506,P=0.009),however,there was no significant differences in haze grading in postoperative 3 months and 6 months between the two groups (x2 =2.199,P =0.699;x2 =1.154,P =0.562).Conclusions Brachytherapy of 0.5％ loteprednol etabonate eye drops appears to have a similar effect in antiinflammation and inhibition of haze to the long-term therapy of 0.1％ fluorometholone eye drops after LASEK.Furthermore,topical application of 0.5％ loteprednol etabonate eye drops dose not increase the risk of ocular hypertension.

Research progress of Galectin-1 in the development of tumor / 中国医师杂志

Nowadays more and more biologists and immunologists focus on Galectin-1 due to the in -depth study of Galectins.As one of the important member of Galectins,Galectin-1 distributes widely,exists in a variety of tissues and cells,involves in cell adhesion,proliferation,apoptosis and inflammatory reaction,and results in a variety of physiological and pathological process.Recent studies have found that Galectin-1 expression in a variety of malignant tumor with a close relationship with tumor occurrence,invasion,development,anti-tumor immunity,and metastasis.It may be a potentially new target for cancer and inflammation therapies.This present paper reviews the current research about Galectin-1 and tumor progression.

Clinical study of higher order wavefront aberrations with a Tscherning aberrometer / 北京大学学报(医学版)

Objective: To study the higher order aberrations of emmetropic and ametropic eyes with wavefront aberrometer. Methods: Forty of cases 77 emmetropic and ametropic eyes were measured with an aberrometer based on Tscherning's principle with the pupils dilated. The Zernike coefficients and root mean square values of wavefront aberrations up to the 6th order were recorded and statistically analyzed. Results: The C06,C07,C08,C12,C13,C14,C24,C26,and C27 were significantly different from zero under 7 mm pupil size and the C06,C10,C12,C23,and C24 were significantly different from zero under 4 mm pupil size. There was no significant difference of higher order wavefront aberrations between emmetropic and ametropic eyes. Comparing the age of 40 years or less with the age over 40 years, there were significant differences in RMS3 between the two under 7 mm pupil size, and statistical diffenences in RMS6 and RMSh between the two under 4 mm pupil size. Conclusion: There are certain higher order wavefront aberrations in the normal human eyes, especially with the pupis dilated. No differences are found in higher order aberrations between emmetropic and ametropic eyes. The higher order aberrations of the age over 40 years are more than those of the age of 40 years or younger.

The role of the posterior corneal parameters measured by Pentacam in subclinical keratoconus screening / 眼科

Objective To estimate the role of the posterior corneal parameters measured by Pentacam in screening subclinical keratoconus.Design Retrospective case-controlled study.Participants Forty five healthy subjects(73 eyes),14 keratoconus patients (20 eyes),43 subclinical keratoconus patients(58 eyes).Methods Based TOPOLYZER and biomicroscope signs,eyes were diagnosed as subclinical keratoconus and keratoconus to compare the differnces of related posterior corneal parameters provided by Pentacam in normal eyes and subclinical keratoconus or keratoconus eyes.Main Outcome Measures Back-Diff(6 mm) max,Back-Diff(6 mm )min, Back-Difference(6 mm),Back-Rmin,Back-Astig.Results The parameters which were statistically different between normal corneas and clinical keratoconus,normal corneas and subclinical keratoconus include Back-Diff(6 mm)max(P

Comparison of laser in situ keratomileusis and laser-assisted subepithelial keratectomy for myopia more than-10.00 diopters / 北京大学学报(医学版)

0.05).There were more complaints of postoperative pain and discomfort after LASEK procedure.No severe vision threatening complications in these two groups were found.Conclusion:Both LASIK and LASEK are safe and effective in treating eyes with severe myopia.