Method for noninvasive determination of hemoglobin content in biological tissues

We have developed a simple and efficient method for determining the hemoglobin concentration in biological tissues, based on spatially resolved measurements of the diffuse reflectance of the tissue at λ = 524, 578, and 662 nm (or 773 nm) using multiple regressions between the measured parameters and the hemoglobin concentrations. The method takes into account the presence in the blood of the major hemoglobin derivatives (oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin, and methemoglobin) and eliminates the effect of the parameters of the top layer of the biological tissue (for example, the epidermis of the skin) and the bulk scattering coefficient of the tissue on the measurement results. Based on numerical Monte Carlo experiments, we have estimated the uncertainties in determining the hemoglobin concentration in skin tissues when its structural and biochemical parameters are all variable.     

Digital image watermarking using gyrator transform and chaotic maps

We propose a new method for digital image watermarking using gyrator transform and chaotic maps. Four chaotic maps have been used in the proposed technique. The four chaotic maps that have been used are the logistic map, the tent map, the Kaplan-Yorke map and the Ikeda map. These chaotic maps are used to generate the random phase masks and these random phase masks are known as chaotic random phase masks. A new technique has been proposed to generate the single chaotic random phase mask by using two chaotic maps together with different seed values. The watermark encoding method in the proposed technique is based on the double random phase encoding method. The gyrator transform and two chaotic random phase masks are used to encode the input image. The mean square error, the peak signal-to-noise ratio and the bit error rate have been calculated. Robustness of the proposed technique has been evaluated in terms of the chaotic maps, the number of the chaotic maps used to generate the CRPM, the rotation angle of the gyrator transform and the seed values of the chaotic random phase masks. Optical implementation of the technique has been proposed. The computer simulations are presented to verify the validity of the proposed technique.     

Noise impact assessment by utilizing noise map and GIS: A case study in the city of Chungju, Republic of Korea

In this study, a scheme to develop a noise map and noise impact assessment method using GIS has been suggested. After developing a road-traffic noise map for the city of Chungju, Republic of Korea, noise impact assessment was performed through analyzing the map. A 3-dimensional terrain model was generated using digital maps and building models were prepared using the information from draft and digital maps. To develop a noise evaluation model, a noise-source map for each road was generated. The noise levels at 25 locations close to roads were measured and compared with the expected noise levels to verify the developed noise map. An excess noise map was generated by comparing the road-traffic noise map with a noise-standard map. Using the excess noise map, the areas exceeding environmental noise standards were effectively evaluated through a GIS space analysis. The 3-dimensional facade noise map was generated to calculate the number of people exposed to a certain noise level.     

Four-wavelength time-resolved optical mammography in the 680-980-nm range

What is to our knowledge the first instrument for time-resolved optical mammography operating at wave-lengths longer than 900 nm has been developed. It is a scanning system that relies on the acquisition of time-resolved transmittance curves at 683, 785, 912, and 975 nm, with a total measurement time of approximately 5 min for an entire image. Breast structures and lesions can be discriminated based on the different absorption and scattering properties at the four wavelengths, which reflect different contributions of oxyhemoglobin, deoxyhemoglobin, water, and lipids, as well as distinct structures. The system is currently used in a European clinical trial.     

高光谱图像中基于端元提取的小目标检测算法

针对高光谱图像中小目标检测问题,提出了一种基于端元提取的目标检测算法。该算法利用主成分分析的变换矩阵来构造投影算子,把原始图像投影到该算子构成的正交子空间后,大概率的背景信息得到抑制,从而突出了小概率的目标;在完成背景信息抑制的基础上,利用迭代误差分析方法进行端元的自动提取;根据所提取出的目标端元的光谱,结合光谱角度匹配技术完成目标物的检测。为了验证新方法的有效性,利用高光谱数据进行了实验研究,并与经典的RX算法的检测结果相比较。实验结果表明提出的基于端元提取的算法不需要目标的任何先验知识就能达到比较好的目标探测效果,对RX算法检测效果不太理想的小目标也能准确识别。     

Thin Film Waveguide Sensor for Measurement of the Absorption Coefficient of Hemoglobin Derivatives

A simple method for determining the absorption coefficient of oxyhemoglobin and deoxyhemoglobin in human blood is proposed. The method is based on a variation of the complex propagation constant of guided wave in a thin-film optical waveguide. On the waveguide layer, a serial multi-channel sample chamber is constructed to vary the interaction length between the evanescent field and the sample, and the dependence of the sensor response on the interaction length is investigated for various concentrations of two hemoglobins. The response of this sensor is linearly proportional to the interaction length and the concentration of the two hemoglobins. The attenuation constant due to the evanescent field absorption between the channels is experimentally obtained with the designed sensor, and the absorption coefficient is determined by the proposed method. The determined absorption coefficients coincided with those obtained by conventional transmission measurement.     

Laser-induced photodissociation of carboxyhemoglobin: An optical method for eliminating the toxic effect of carbon monoxide

We propose and examine an optical method for eliminating the toxic effect of carbon monoxide. The developed method is based on laser-induced photodissociation of carboxyhemoglobin in blood vessels and capillaries. By numerical simulation of the interaction of laser radiation with tissue, we calculate the spectra of the action of carboxyhemoglobin and oxyhemoglobin in cutaneous blood vessels. We show that, despite the sufficiently strong overlap of the action spectra of carboxyhemoglobin and oxyhemoglobin, the substantial difference in the quantum yield values makes it possible to develop an optical method for eliminating the toxic effect of carbon monoxide. We determine the criteria for the efficiency of laser-induced photodissociation of carboxyhemoglobin under direct action on lung alveoli through the skin tissue and intravenously.     

基于高光谱特征的迷彩伪装评价

伪装效果分析是伪装设计和识别的重要环节,为了对高光谱探测下的目标伪装效果进行有效评价,结合高光谱图像光谱分辨率较高的特点,提出了一种基于高光谱特征的迷彩伪装评价方法。在光谱维,分析并提取伪装目标的光谱特征。在空间维,对图像第一主成分进行多层小波分解,提取高频分量和低频分量的比值、水平分量和垂直分量的比值以及低频图像的对比度、相关性、能量、同质性等6个特征作为纹理特征。利用欧氏距离分别计算光谱特征距离与纹理特征距离,最后将二者进行综合,距离越小说明伪装效果越好。实验数据表明:本文的方法可以量化高光谱成像下的迷彩伪装效果,评价客观。得到迷彩雨衣与草坪背景之间的综合距离为1.3225,两者融合效果最好。     

Hemoglobin magnetism in aqueous solution probed by muon spin relaxation and future applications to brain research

A marked difference in spin relaxation behavior due to hemoglobin magnetism was found for positive muons (μ⁺) in deoxyhemoglobin in comparison with that observed in oxyhemoglobin in aqueous solution at room temperature under zero and external longitudinal magnetic fields upto 0.4 Tesla. At the same time, small but significant unique relaxation pattern was observed in nonmagnetic oxyhemoglobin. Combined with our previous measurements on hemoglobin in human blood, application of this type of measurement to the studies of the level of oxygenation in various regions of the human brain is suggested.     

高光谱图像中纯光谱提取方法

利用线性解混合方法处理高光谱图像数据,需要获取存在于光谱图像中的纯光谱.目前的纯光谱提取方法都需要复杂的运算,并且都没有被证明具有普遍适用的特点,在特征空间对光谱图像中信息存在形式进行有效分析的基础上,提出基于特征空间分析和光谱相关制图法相结合的纯光谱提取方法(FSASCM),具有复杂度低、对大多数高光谱图像数据普遍适用的特点,     

Image encryption based on the multiple-parameter discrete fractional Fourier transform and chaos function

In recent years, the chaos-based cryptographic algorithms have suggested some new and efficient ways to develop secure image encryption techniques. In this paper, we propose a new approach for image encryption based on the multiple-parameter discrete fractional Fourier transform and chaotic logistic maps in order to meet the requirements of the secure image transmission. In the proposed image encryption scheme, the image is encrypted by juxtaposition of sections of the image in the multiple-parameter discrete fractional Fourier domains and the alignment of sections is determined by chaotic logistic maps. This method does not require the use of phase keys. The new method has been compared with several existing methods and shows comparable or superior robustness to blind decryption.     

Brain tissue classification based on DTI using an improved Fuzzy C-means algorithm with spatial constraints

We present an effective method for brain tissue classification based on diffusion tensor imaging (DTI) data. The method accounts for two main DTI segmentation obstacles: random noise and magnetic field inhomogeneities. In the proposed method, DTI parametric maps were used to resolve intensity inhomogeneities of brain tissue segmentation because they could provide complementary information for tissues and define accurate tissue maps. An improved fuzzy c-means with spatial constraints proposal was used to enhance the noise and artifact robustness of DTI segmentation. Fuzzy c-means clustering with spatial constraints (FCM_S) could effectively segment images corrupted by noise, outliers, and other imaging artifacts. Its effectiveness contributes not only to the introduction of fuzziness for belongingness of each pixel but also to the exploitation of spatial contextual information. We proposed an improved FCM_S applied on DTI parametric maps, which explores the mean and covariance of the feature spatial information for automated segmentation of DTI. The experiments on synthetic images and real-world datasets showed that our proposed algorithms, especially with new spatial constraints, were more effective.     

超光谱成像探测系统的图谱标定和评估

超光谱成像是一种场景图谱合一的技术,在战场侦察中得到了迅速应用。超光谱成像系统的标定是确定其输出准确数值的过程。分析了一种基于背照减薄CCD和凹面光栅成像光谱部件的UV/Vis/NIR超光谱军用探测系统,其光谱分辨力为3.3 nm;探讨了0.25～1.1μm工作波段内超光谱成像系统的标定和评估方法,详细介绍了以带有测试靶均匀辐射源为对象的空间成像质量评估、以激光和Hg灯为基础的光谱质量评估以及利用高精度标准辐射源的辐射性能标定。在经过多步辐射校正和光谱真实性检测验证后,最终获得的景物反射率光谱曲线真实反映了光谱特性,满足了0.2mrad的空间分辨力和±0.5％色散线性率的精度要求并在军用探测系统中进行了反伪装的成功应用。     

Spectrum of the effect of laser radiation on hemoglobin of the blood vessels of skin

We suggested and consider the primary mechanism of biostimulation and of the therapeutic effect of low-level laser radiation caused by a local increase in the effectiveness of oxygen transfer by oxyhemoglobin of the blood vessels of skin. The spectra of the effect of laser radiation on oxyhemoglobin and hemoglobin of the blood vessels of skin are presented which were obtained using a method of numerical simulation with allowance for the optical characteristics of skin and for the depth of penetration into it of radiation of different wavelengths. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 6, pp. 877–860, November–December, 1998.     

基于投影寻踪的高光谱图像目标检测算法

针对高光谱图像中小目标检测问题,提出了一种投影寻踪结合遗传算法的目标检测方法.该方法采用对异常分布敏感的偏度和峰度作为投影指标,实数编码的加速遗传算法搜索最佳投影方向.利用高光谱数据对所提出的方法进行了实验研究.结果表明,该方法能够快速、可靠的检测出小目标.     

基于二阶离散变分方法的非线性映射参数估计

提出一种估计非线性映射未知参数的二阶离散变分方法.首先针对非线性离散混沌系统, 利用变分方法导出了伴随方程和目标泛函梯度, 以此为基础利用二阶离散变分方法给出了二阶伴随方程和精确计算Hessian矩阵-向量乘积的显式表达式; 其次设计了估计非线性映射未知参数的新算法, 并以此对Hyperhenón映射和二维抛物映射中的未知参数进行了精确的估计. 数值仿真结果表明了该方法的有效性和优点. 关键词： 非线性映射 参数估计 二阶离散变分方法 伴随方程     

Identification of wheat grain in different states based on hyperspectral imaging technology

Abstract

Nondestructive identification of wheat grains in different states plays an important role in improving the quality of wheat products. This study investigated the possibility of using hyperspectral imaging techniques to discriminate healthy wheat grain, germinated wheat grain, mildewed wheat grain, and shriveled wheat grain (wheat grain infected with fusarium head blight). Both sides of individual wheat kernels were subjected to hyperspectral imaging (866.4–1701.0?nm) to acquire hyperspectral cube data. Spectral data were preprocessed by using standardization and multiple scattering correction. In addition, the principal component loading method was used to extract the characteristic wavelengths of both sides of wheat grains. The sample is divided into calibration set, test set, and validation set. The data of the calibration set are used to train the partial least squares discriminant analysis model, K-nearest neighbor model, and the support vector machine model, and the test set data are used to test the model. The results show that spectral data of both sides can achieve good classification results, while the reverse spectral data perform better. By comparing with each other, the support vector machine model is selected as the best classification model. Finally, using two hyperspectral images (reverse side) that are not involved in training and testing to verify the accuracy of the established support vector machine model, and the classification effect maps of the four wheat grains were visualized. The results indicate that nondestructive classification of wheat grains in different states is feasible based on hyperspectral imaging technology.     

High-resolution in vivo imaging of blood vessels without labeling

We demonstrate that both oxyhemoglobin and deoxyhemoglobin have sequential two-color, two-photon absorption properties that can serve as endogenous contrasts in microvasculature imaging. Using a sensitive modulation transfer technique, we are able to image hemoglobin in red blood cells with micrometer resolution, both in vitro and in vivo. We show that excellent contrast from hemoglobin without any labeling can be obtained in tissue.     

M?ssbauer studies of hemoglobin in erythrocytes exposed to neutron radiation

We studied radiation effects on the stability of various states of hemoglobin (Hb) in red blood cells (RBC) irradiated with a very low dose of neutron rays, 50?μGy. We investigated RBCs isolated from blood of healthy donors. M?ssbauer spectroscopy was applied to monitor different forms of Hb. Our results show, for the first time, that oxyhemoglobin (OxyHb) and deoxyhemoglobin (DeoxyHb) are two Hb forms sensitive to such a low neutron radiation. Both Hbs change into a new Hb form (Hb_irr). Additionally, OxyHb transfers into HbOH/H₂O, which under our experimental conditions is resistant to the action of neutron rays.     

Diffuse optical measurement of blood flow, blood oxygenation, and metabolism in a human brain during sensorimotor cortex activation

We combine diffuse optical and correlation spectroscopies to simultaneously measure the oxyhemoglobin and deoxyhemoglobin concentration and blood flow in an adult human brain during sensorimotor stimulation. The observations permit calculation of the relative cerebral metabolic rate of oxygen in the human brain, for the first time to our knowledge, by use of all-optical methods. The feasibility for noninvasive optical measurement of blood flow through the skull of an adult brain is thus demonstrated, and the clinical potential of this hybrid, all-optical noninvasive, methodology can now be explored.