Optimal Combination of Image Denoisers.

Given a set of image denoisers, each having a different denoising capability, is there a provably optimal way of combining these denoisers to produce an overall better result? An answer to this question is fundamental to designing an ensemble of weak estimators for complex scenes. In this paper, we present an optimal combination scheme by leveraging the deep neural networks and the convex optimization. The proposed framework, called the Consensus Neural Network (CsNet), introduces three new concepts in image denoising: 1) a provably optimal procedure to combine the denoised outputs via convex optimization; 2) a deep neural network to estimate the mean squared error (MSE) of denoised images without needing the ground truths; and 3) an image boosting procedure using a deep neural network to improve the contrast and to recover the lost details of the combined images. Experimental results show that CsNet can consistently improve the denoising performance for both deterministic and neural network denoisers.

Denoising Stimulated Raman Spectroscopic Images by Total Variation Minimization.

High-speed coherent Raman scattering imaging is opening a new avenue to unveiling the cellular machinery by visualizing the spatio-temporal dynamics of target molecules or intracellular organelles. By extracting signals from the laser at MHz modulation frequency, current stimulated Raman scattering (SRS) microscopy has reached shot noise limited detection sensitivity. The laser-based local oscillator in SRS microscopy not only generates high levels of signal, but also delivers a large shot noise which degrades image quality and spectral fidelity. Here, we demonstrate a denoising algorithm that removes the noise in both spatial and spectral domains by total variation minimization. The signal-to-noise ratio of SRS spectroscopic images was improved by up to 57 times for diluted dimethyl sulfoxide solutions and by 15 times for biological tissues. Weak Raman peaks of target molecules originally buried in the noise were unraveled. Coupling the denoising algorithm with multivariate curve resolution allowed discrimination of fat stores from protein-rich organelles in C. elegans. Together, our method significantly improved detection sensitivity without frame averaging, which can be useful for in vivo spectroscopic imaging.

Steatocystoma multiplex confined to the scalp with concurrent alopecia.

Steatocystoma multiplex (SM) is an uncommon disorder of the pilosebaceous unit characterized by the development of numerous sebum-containing dermal cysts which rarely involves the scalp. Here, we report a case of a 50-year-old man with multiple cystic nodules and alopecic patches on his scalp. On histopathological examination, the folded cyst was found to be lined by stratified squamous epithelium, while flattened sebaceous gland cells were identified in the cystic wall. Pigment casts were present in the hair papillae and perifollicular regions, suggesting trichotillomania as a possible cause of the observed alopecia. This case appears to represent an unusual clinical manifestation of SM.

Giant acquired digital fibrokeratoma occurring on the left great toe.

Acquired digital fibrokeratoma is an uncommon, benign fibrous tumor which usually occurs in adults as a solitary lesion. The most frequent locations are fingers and toes and the size of the tumor is generally small, around 3~5 mm. An 18-year-old female presented with a solitary, skin-colored, round and protruded nodule of the left great toe. The size of nodule was 2.5×1.6×1.4 cm. Histopathologic examination revealed typical findings of acquired digital fibrokeratoma. Herein, we report a giant acquired digital fibrokeratoma.

Vitiligo Coexistent with Nevus Depigmentosus: This Was Treated with Narrow-Band UVB and These Lesions Were Followed Using the Mexameter®, a Pigment-Measuring Device.

Nevus depigmentosus (ND) is a congenital, non-progressive, hypopigmented lesion that is usually stable throughout an affected individual's lifetime. The clinical features of vitiligo are similar to those of ND, but the two diseases have different treatment responses and prognoses. We report here on a rare case of vitiligo that was coexistent with ND. Both conditions were treated with narrow-band UVB. An 11-year-old boy presented with two distinct types of hypopigmented lesions, one on the forehead and the other on his back. The first was a hypopigmented patch with leukotrichia, and it was incidentally discovered 3 months before the child was examined at our clinic and it had rapidly increased in size. The second hypopigmented patch was detected at birth and it had slowly been increasing in size. The hypopigmented lesion on the child's forehead was diagnosed as vitiligo, and the one on his back as ND. Once- or twice-weekly narrow-band UVB treatment was initiated. Improvements in the two lesions were assessed with clinical photography and using a Mexameter® (Courage-Khazaka Electronic, Germany), which is a pigment-measuring device.

A case of linear lichen planus pigmentosus.

Lichen planus pigmentosus (LPP) is chronic pigmentary disorder that shows diffuse or reticulated hyperpigmented, dark brown macules on the sun-exposed areas such as the face, neck and other flexural folds. Clinically, it is different from classical lichen planus because LPP has a longer clinical course and it manifests with dark brown macules. In case of LPP, involvement of the scalp, nail or mucosal area is rare. The histopathological findings of the lesions show an atrophic epidermis, the presence of melanophages and a vacuolar alteration of the basal cell layer with a sparse lymphohistiocytic lichenoid infiltration. Although there have been a few reports of LPP, there have only 3 cases of linear LPP along the lines of Blaschko in the Korean dermatologic literature. Our patient had lesions on the neck and chin with a linear pattern. In this report, we describe a very rare case of LPP with a linear distribution related to Blaschko's lines on the neck and chin areas.

A Case of p-ANCA-Positive Propylthiouracil-Induced Pyoderma Gangrenosum.

Propylthiouracil is a common medication used in patients with hyperthyroidism; it can cause perinuclear antineutrophil cytoplasmic antibodies (p-ANCA) in some patients with Graves' disease. This antibody has been associated with various forms of vasculitis and neutrophilic dermatosis. Herein, we report a patient who presented with cutaneous manifestations of pyoderma gangrenosum with simultaneous development of p-ANCAs during PTU therapy for Graves' disease.