Segmentation of an optic disk location is a very essential task for retinal image analysis. Most of the pervious method uses the principal component analysis method, which are computationally complex. This paper presents a simple and semi automatic approach for segmentation of the optic disc in retinal images using thresholding and boundary extraction. First, the true colour Retinal images are converted to gray image and then image is enhanced using histogram equalization. This improves the efficiency of the conventional thresholding method. The proposed method of segmentation utilizes gray level thresholding for segmentation and then morphological operators are used for extracting the optical disk. The method is tested on the different optical disc images. The method is less complex and efficiently recognizes the boundary of the optic disc and also evaluates the optical canter. The optical canters are tabulated for original and corrupted images.
Diketopyrrolopyrrole
(DPP)-based molecular semiconductors exhibit
intriguing optical and charge transport properties. Herein, we rationally
design a series of electronically identical but structurally distinct
Hamilton receptor (HR)-based supramolecular assembly of DPP. The HR
endows supramolecular assemblies via hydrogen bonding with enhanced
structural ordering and excitonic couplings. The mechanism of supramolecular
self-assembly was probed by diffusion ordered spectroscopy (DOSY)
nuclear magnetic resonance (NMR) and solid-state IR spectroscopy studies.
We investigated the morphology of self-assembly, photophysical and
electrochemical properties and compared them with the identical DPP
molecular structures without HRs. The microstructure of self-assembly
was probed with atomic force microscopy in thin films. Subsequently,
the influence of solid-state packing was studied by single-crystal
X-ray diffraction. The single-crystal structure of HR-TDPP-C
20
reveals slipped stack arrangements between the two neighboring chromophores
with π–π stacking distance and slip angle of 3.55
Å and 35.4°, respectively. Notably, the slight torsional
angle of 1° between thiophene and lactam rings and small π–π
stacking distance suggest a significant intermolecular coupling between
thiophene (D) and lactam (A) rings. This intramolecular coupling between
two π–π chromophore stacks manifests in their optical
properties. In this manuscript, we report rational design and synthesis
of supramolecular self-assembly of DPP with a collection of compelling
structural and optical properties.
Image enhancement methods are widely used for improving the feature and quality of the images. Researchers have designed various contrast enhancement methods in the past. But since underwater image contain low contrast and resolution due to poor visibility conditions and refractions of light rays. Thus analysis and identification of the underwater object is a challenging and difficult task. In this paper presents a comparative analysis of various contrast enhancement techniques for such underwater images. Performance of contrast limited adaptive histogram equalization (CLAHE) method is compared with contrast stretching, global histogram equalization (HE) Brightness preserving Bi-histogram equalization (BBHE) and finally Dual Sub-Image histogram equalization (DSIHE) methods. Different colour underwater images are enhanced in the RGB colour space. The performance is evaluated based on discrete entropy, signal to noise ratio (SNR) and Standard deviation difference and the mean brightness. Performance of methods is evaluated under various type of underwater image environment.
A one-dimensional phase-modulated NMR experiment, which distinguishes the partially resolved peaks and accelerates the data acquisition due to reduced dimensionality, is reported for differentiating spin systems, with application to chiral discrimination. The multifarious utility of the technique is demonstrated in plenteous examples.
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