Disinfestation of stored wheat grain and flour using gamma rays and microwave heating

Samples of wheat grain and flour (20 gm of each) were infested with 20 larvae or 5 pairs of adult insects of Tribolium confusum, Lasioderma serricorne, Corcyra cephalonica or Rhyzopertha dominica. The infested samples were tested as follows : (1) microwave heating at four temperature levels 40, 45,50 and 55 °C, for exposure times from10 to 50 s; (2) gamma irradiation over the dose range of 0.5-4 KGy; (3) gamma irradiation + microwave heating. Complete kill of all stages tested was achieved at 50 °C with an exposure time of 50 s. A dose of 2 KGy induced 100% mortality of R. dominica after three days, but it took up to 7 days for all T. confusum and L. serricorne adults to die after a 4-KGy exposure. All insects died within 24 h when exposed to the combination of 1KGy + 50 °C for 30 s.Biochemical analyses on the samples of wheat grain and flour subjected to those treatments at which high mortality was obtained generally showed no detectable changes in the quality of protein, fat, fiber, carbohydrates or ash. The germination of wheat grain was lowered after treatment with microwave radiation but was not affected by a dose of 1 KGy gamma radiation.     

Inactivation of aflatoxigenic fungi and the reduction of aflatoxin B1 in vitro and in situ using gamma irradiation

Detailed investigation on the effect of gamma (γ) irradiation on germination, sporulation, and growth of aflatoxigenic moulds (Aspergillus parasiticus 2999, Aspergillus flavus 305, and Aspergillus niger 388), as well as on the reduction of aflatoxin B₁ (AFB₁) level in artificially and naturally contaminated maize/feed samples was performed. The results of in vitro and in situ experiments with aflatoxigenic moulds demonstrated that 5 kGy-γ irradiation manages to prevent sporulation, germination and growth of the tested moulds both when in form of a pure and when in form of a mixed culture. In the feed samples artificially contaminated with AFB₁ (50 μg kg⁻¹) 5 kGy-γ irradiation reduced AFB₁ level by around 60%, while 10 kGy-dose reduce it for around 85%. Similarly, in feed samples spiked with AFB₁ in the concentrations of 100 μg kg⁻¹ 5 kGy-dose reduced the AFB₁ level by approximately 70%, while the dose of 10 kGy reduced it by approximately 90%. The experiments on naturally contaminated maize samples (n = 30) confirmed these observations; following a 5 kGy-irradiation, the overall mean AFB₁ reduction equalled to 69.8%, while the irradiation with a 10 kGy-dose achieved the overall mean toxin reduction of 94.5%. The obtained results indicate that γ irradiation can be used to prevent the growth of aflatoxigenic moulds and to reduce the AFB₁ levels in various goods intended for animal and human consumption, thus minimizing the animal and human exposure to this carcinogenic mycotoxin.     

基于上下文语义分割信息的缺销螺丝部件识别

针对目前图像视觉领域对输电线路缺销螺丝部件研究较少,且在传统图像处理方法上,螺丝的识别精度不高等问题。文章采用一种基于上下文语义分割信息的缺销螺丝识别方法,在Deeplab v3+网络的基础上,对输电线路数据集进行图像裁剪分块和自适应Gamma校正增强预处理,将缺销螺丝识别的mIoU提升了17%左右;对于普通螺丝误识别,提出了结合上下文语义分割信息的方法,将分割出缺销螺丝区域分别和周围若干部件区域进行拓扑关系分析,根据拓扑关系类别排除误识别到的普通螺丝。通过多组实验结果表明,采用预处理和结合上下文语义信息的缺销螺丝识别方法要优于Deeplab v3+算法。     

An improved Gamma correction model for image dehazing in a multi-exposure fusion framework

A usual problem encountered during bad weather conditions is the degraded image quality due to haze/fog. In basic Gamma correction method there is always an uncertainty regarding the choice of a particular exponential factor, which improves the quality of the input image because of the nonlinearity involved in the process. This issue has been solved in this study by proposing a modified Gamma correction method, in which the exponential correction factor is varied incrementally to generate images. We also propose the implementation of an automatic image selection criterion for fusion which helps chose images with varied and distinct features. The implementation of the multi-exposure fusion framework is done in the hue-saturation-value color space which has close resemblance with the human vision. The intensity channel of the selected images is fused in the gradient domain which captures minute details and takes an edge as compared to other conventional fusion based methods. The fused saturation channel is obtained by averaging fusion followed by enhancement using a non-linear sigmoid function. The hue channel of the input hazy image is left unprocessed to avoid color distortion. The experimental analysis demonstrates that the proposed method outperforms most of the single image dehazing methods.     

MEASUREMENT OF LIQUID FILM THICKNESS ON THE SURFACE OF A PARTIALLY IMMERSED VERTICAL ROTATING DISK USING A GAMMA CAMERA

The liquid film thickness on the surface of a partially immersed vertical rotating disk was determined using a gamma camera imaging system to measure the amount and spatial distribution of a dissolved 99m-Technetium pertechneiate radionuclide tracer. The method allows simultaneous measurement of film thickness in individual regions having a projected surface area of less than 1 cm² and distributed over the entire exposed surface of the disk. Measurement accuracy is limited only by counting statistics, and for these studies was better than ±4% of the absolute film thickness.

Experiments were conducted with a 31.5 cm diameter aluminum disk rotating from 18 to 99 revolutions per minute; seven aqueous solutions of glycerol and polyvinylpyrrolidone (PVP) within the viscosity range 1 to 19.7 cp were used. The average film thickness varied between 0.045 and 0.45 mm, and was a function of solution viscosity and disk angular velocity. Local film thickness was dependent on both radial and angular position, and varied from 0.5 to 3.0 times the average thickness. This variation may be important to the characterization of mass transfer when diffusion through the film is a rate limiting step     

基于Gabor纹理特征的人脸识别方法*

为了降低人脸Gabor特征的维数,提出了一种新的基于Gabor幅值的纹理表征(GMTR)方法用于人脸识别。GMTR由伽玛分布(ΓD)拟合Gabor幅值的分布来刻画,拟合的ΓD参数作为纹理特征。在FERET和Yale人脸库上的实验结果显示GMTR的识别性能优于传统的Gabor幅值特征,表明纹理特征具有更强的鉴别力。     

Gamma值对LCD显示器色彩影响的实验研究

在色彩管理系统中,为了产生一致的颜色效果,需要对用来观察图像色彩的显示器进行校正与特性化,在显示器的校正与特性化中,常常会涉及Gamma值、白点坐标、色温、三原色荧光荆色度值等参数的设定,其中Gamma值的设定至关重要,不同的Gamma值参数设定使显示器显示的亮度和颜色有较大的差别。显示器作为图像信息输出的主要设备,Gamma值对LCD显示器色彩的影响实验数据有更实际的应用价值。实验测量了不同Gamma值下10块Macbeth公司提供的colorchecker样品颜色的三刺激值X,Y,Z和色度值L,a,b,并计算了其色差,得出了Gamma值对LCD显示器色彩的影响,以得到较好的LCD颜色管理模式,为图像处理技术奠定基础。     

基于剪切波域改进Gamma校正的医学图像增强算法

为了解决医学图像在采集和传输过程中引入噪 声和干扰导致图像质量恶化从而严重影响医学诊断的问题,提出 一种基于剪切波(shearlet)域改进Gamma校正的图像增强方法。首先,通过剪切波变换,把 图像分解成高频 部分和低频部分;其次,用改进的Gamma校正处理剪切波分解后的低频部分以调整图像的整 体对比 度,采用改进的自适应阈值函数对高频部分进行去噪;最后,把剪切波反变换的重构图 像进行模糊对比 增强,以突出图像的细节信息。实验结果表明,本文算法的峰值信噪比(PSNR )、结构相似度(SSIM)和 绝对均值差(MAE)优于其他对比算法,尤其是PSNR的提升更加明显。这些 客观指标说明,本 文算法不仅能有效地抑制噪声,而且能明显改善增强对比度。从主观方面观察,本文算法与 其他算法相比,能获得更好的视觉效果。     

Thermodynamic Properties of HFC-236ea

The density of gaseous and liquid 1,1,1,2,3,3-hexafluoropropane (HFC-236ea) and the speed of sound in liquid HFC-236ea have been studied by a γ-attenuation technique, an ultrasonic interferometer, and an isochoric piezometer method over the temperature range of 263–423 K at pressures up to 4.05 MPa. The purity of the samples used throughout the measurements is 99.68 mol%. The pressures of the saturated vapor were measured over the same temperature range. The experimental uncertainties of the temperature, pressure, density, and speed-of-sound measurements were estimated to be within ±20 mK, ±1.5 kPa, ±(0.05–0.30)%, and ±(0.05–0.10)%, respectively.     

A Gamma–normal series truncation approximation for computing the Weibull renewal function

This paper presents a series truncation approximation for computing the Weibull renewal function. In the proposed model, the n-fold convolution of the Weibull Cdf is approximated by a mixture of the n-fold convolutions of Gamma and normal Cdfs. The mixture weight can be optimally determined and fitted into a very accurate linear function of Weibull shape parameter β. Major advantages of the proposed model include:

(a) The proposed model and its parameters can be directly written out. Using the proposed model, the renewal density and variance functions can be easily evaluated.

(b) The proposed model includes Gamma and normal series truncation models as its special cases. It is easy to be implemented in Excel. The series converges fairly fast.

(c) Over the range of β(0.87,8.0), the maximum absolute error is smaller than 0.01; and over , the maximum absolute error is smaller than 0.0037.

(d) The model can be easily extended to non-Weibull case with some additional work.