MAXIMUM COMPONENTS INTEGRATION FOR IMAGE PROCESSING: AN APPLICATION OF ULTRASOUND FOR DETECTION OF SMALL OBJECTS IN CONTAINERS

Detection of small objects, those that lie on the bottom or stick to the wall of containers, constitutes a challenging issue for ultrasonic detection techniques. This is because echo signals from the object are fused with that of the inner surface of the container when subjected to ultrasound scanning. This study proposes a maximum component integration method based on the short‐time Fourier transform algorithm to detect these objects. Experiments were conducted using glass fragments of about 2 × 2 × 2 mm³ to test the proposed method. Compared with other signal‐processing methods (statistical calculations, backscattered amplitude integral and maximum frequency calculation), this method is able to make selective and full use of multiecho information, and hence demonstrated to have improved detection ability to the extent that it can detect small glass fragments contained inside glass containers. Principles are introduced for choosing the optimized WINDOW size and signal size to be processed when applying this method.     

Ultrasonic internal defect detection in cheese

Different ultrasonic signals and detection techniques were used and compared to detect internal foreign bodies present in semi-soft cheeses. The signals were a pulse or a chirp and the detection was carried out by using either correlation with a reference signal or a wavelet decomposition. The principle of the detection consisted in measuring the time of flight of the transmitted signals and of the echoes, the latter in the absence of foreign body should be the double of the former. The presence of a foreign object affected this pattern in several ways. In order to assess the method, a small plastic cylindrical object of 3 mm in diameter was introduced in one half of the cheese and was tested for detection, the second half being used as reference for the control cheese. The results showed that the two signals and the two detection methods were able to localise the transmitted signals and the echo from the opposite face of the cheese under all circumstances. For the foreign body detection, the correlation method gave superior results, in term of signal to noise ratio as well as in term of error rate, while the two signals gave similar results. The analysis of the mean and standard deviation of the signal to noise ratio of the object echo showed that some samples presented peak values close to those due to the noise. Nevertheless, the object was detected in 90% of the tests. There was no significant effect of temperature on the detection technique.     

基于可见/近红外光谱技术的腐坏猪肉检测控制系统设计

目的 设计腐坏猪肉的快速、无损检测控制系统。方法 通过研究可见/近红外光谱技术, 根据其在应用过程中的使用特点并结合实际情况的需求, 设计检测系统的总体方案。结果 设计检测系统方案, 包括检测对象、检测指标, 设计控制系统的结构、功能和工作流程。结论 光纤探头距离样品高度为10 cm, 单个样品检测时间控制在5 s内, 使用DSP作为控制核心, 用于检测猪肉是否腐败。     

Detection of occluded small objects in glass bottles filled with beverages via ultrasound center frequency tracing

Detection of small foreign objects that lie on the bottom or attached to the wall of bottles or containers filled with beverages represents a significant challenge. This is because the echo signals from the object are fused with that reflected from the bottle or container inner surface. The latter has much higher signal energy that masks that of the former. This study formulates the problem as an image construction and processing problem and proposes an algorithm to facilitate object detection using the constructed images. The algorithm is based on the longitudinal (vertical) tracing of a center frequency component obtained using short time Fourier transform (STFT) in conjunction with a transversal (horizontal) differentiation of the image pixels. This method is demonstrated to have improved ability to detect small glass fragments contained inside a glass bottle.     

Free radicals in velvet bean seeds (Mucuna pruriens L. DC.) and their status after γ-irradiation and conventional processing

Free radicals in velvet bean seeds, a nutarceutically valued legume were examined by electron spin resonance (ESR) spectroscopy. The status of free radicals present naturally, after irradiation and conventional processing were recorded by entrapping small quantities of seed samples in potassium chloride powder in ESR quartz tubes. The ESR signal at g=2.0055(±0.0001) were more prominent in seed coat than cotyledon portion. Gamma irradiation of seeds (for hygienization and quarantine purposes) at different doses (0, 2.5, 5, 7.5, 10, 15 and 30 kGy) resulted in a dose-dependent increase of signal intensity at g=2.0055 in seed coat as well as in cotyledon. In seed coat, a weak triplet (satellite peak) accompanied the central line. This satellite peak (left line ‘g’) can be used as an authentic indication of radiation treatment of Mucuna seeds and can be employed as one of the detection methods for similarly irradiated legume seeds possessing prominent seed coat. In cotyledon, irradiation at high doses (15 and 30 kGy) showed a significant reduction of the ESR signals (P<0.05), which has been attributed to possible increase in free radical scavengers (particularly polyphenols). Some of the common processing practices such as microwave roasting, flame heating and pounding also generated free radicals similar to irradiation treatments. Results of the present study substantiate the suitability of employing ESR technique for detection of free radicals present naturally or produced after radiation and conventional processing. The results of this study might also be feasible for successful application of gamma irradiation of Mucuna seeds for quarantine purposes.     

Acoustic vibration technology: Toward a promising fruit quality detection method

Understanding fruit quality is an effective way to reduce fruit loss and waste by providing proper strategies for fruit processing and management. Various noninvasive technologies have been developed for assessing fruit quality. Among them, acoustic vibration technology has received considerable attention from academics. As the fruit ripens, the physical and biochemical diversities of fruit cell lead to changes in the vibration characteristics of the fruit, which verified the feasibility of assessing fruit firmness by acoustic vibration technology from the microscopic view. Besides, the acoustic and vibration theories also provided the theoretical basis for this technology. The measurement system was mainly consisted of excitation devices, detection sensors, and signal processing modules. By using different excitation methods and devices, the fruit could demonstrate a free or forced vibration. The response signals of fruit were influenced by detection methods and sensors. To meet the requirement of high-throughput detection, noncontact excitation devices and detection sensors were more suitable for on-line applications. In addition, the relative locations of excitation and detection points and the posture style of fruit also had an impact on the measurement results, which should be determined before the test. Moreover, the proper data analysis method was equally important to extract potential parameters to improve the performance of prediction models. This paper provided a comprehensive overview concerning the principle, system composition, data analysis, and on-line applications of acoustic vibration technology, and discussed the perspectives of future trends to promote the intensive study and further extension of this technology.     

混合式生丝断丝检测传感器设计

针对生丝直径很细导致无法准确检测出生丝断丝的问题,依据光电管对射原理,设计出一种检测生丝断丝的传感器。传感器由机械部分和电路部分组成：机械部分包括生丝断丝间接测量机构、光电管安装机构和安装外壳;电路部分包括信号发送、信号接收、信号处理等电路,单片机电路,LED 驱动电路。将传感器安装在纤度机上进行实验,并对生丝断丝前后的输出信号进行采集。结果表明：传感器成功将生丝断丝产生的微弱光信号转换成单片机可识别和处理的电信号,实现了生丝断丝故障的准确检测和报警提醒功能;该传感器在生丝断丝故障检测中具有较高的实用性和有效性。     

On-line detection of eggshell crack based on acoustic resonance analysis

An on-line system based on acoustic resonance was developed for eggshell crack detection. The system employed digital signal processing (DSP) as core processor to collect and analyze the response signal of shell eggs. The effects of excitation point, speed of the conveying system, impact intensity and egg mass on the frequencies response signals were investigated. Based on previous experiments, differences between the signals of intact eggs and cracked eggs were analyzed. Five excited resonance frequency characteristics expressing the differences between intact and cracked eggs were explored as input vectors. A simple and robust calibration model was built to discriminate intact and cracked eggs, while meeting speed requirement of on-line measurement. The identification rates for intact and cracked eggs were 100% and 96.1% respectively. It is concluded that the system has significant potential in the on-line detection of cracked eggs.     

纬纱红外光电检测方法与可靠性

在纺织生产中,气流引纬的纬纱光电检测误检测率较高。本文对纬纱信号的检测处理的一般方法作了较完整的分析,指出纬纱信号的波动与增益放大电路与阀值比较电路的可调电阻的阻值成正态分布,是造成检测可靠度不高的主因。并对可能产生的误判原因进行了分析,给出了改进方法。通过实验,说明纬纱信号的增益过饱和和欠饱和是造成误判的主要原因,对于数字处理方式和模拟方式进行的纬纱信号处理,在放大电路采用增益自动调节的运算放大器是提高检测率的重要手段。     

高效液相色谱-串联质谱法检测副溶血弧菌生物被膜形成过程中的N-酰基高丝氨酸内酯信号分子

N-酰基高丝氨酸内酯(AHLs)是副溶血弧菌的群体感应系统的信号分子,参与微生物的毒力调控,目前缺乏准确检测生物被膜中的信号分子的方法。在现有信号分子HPLC-MS/MS检测条件基础上,针对副溶血弧菌生物被膜生成过程中信号分子定性定量检测方法进行优化。结果显示:无水甲醇:0.1%乙酸铵水为流动相分离效果较优;当选择碰撞能量为10~15 eV时,各信号分子均可形成较高比例的特征碎片离子(m/z)102.1和74.1,并在0~20 μg/L范围内均有良好的线性关系(R2>0.995),采用该法能够检测副溶血性弧菌生物被膜形成过程中产生的C₄-HSL、3-oxo-C₆-HSL和3-oxo-C₁₄-HSL三种信号分子,其中C₄-HSL的量占绝对优势(>91.67%)。在生物被膜形成的前期(0.5~3 d),信号分子的浓度缓慢增长,与生物被膜的生成量成正相关;当被膜进入消散期时(4~5 d),信号分子的浓度快速增长,与被膜生成量呈显著负相关。高效液相色谱-串联质谱法的优化有助于更加有效地检出生物被膜中的信号分子,为更好地认识生物被膜与群体感应信号分子间的调控关系提供支撑。     

Evaluation of electron spin resonance technique for the detection of irradiated mango (Mangifera indica L.) fruits

The electron spin resonance (ESR) technique was examined as a method for the detection of irradiated mango fruits. A symmetric ESR signal at g = 1.988 was detected in the hard seed cover (endocarp), the dry epidermal layer (testa) surrounding the kernel, and the soft kernel portions of the seed from four mango cultivars. the amplitude of the signal in the epidermal layer and seed cover showed a dose-dependent increase over control values. Qualitatively, however, no new signal was observed following irradiation, except that line width increased by 50%. Methyl cellosolve washing greatly reduced the intensity of the endogenous and radiation (1.0 kGy)-induced ESR signals in the seed cover; results suggest phenolic substances as the source of free radicals. the similarity of naturally occurring ESR signals to that induced by irradiation seems to restrict the practical utility of this method in irradiated mangoes.     

The combination of quantitative PCR and western blot detecting CP4-EPSPS component in Roundup Ready soy plant tissues and commercial soy-related foodstuffs

With the widespread use of Roundup Ready soy (event 40-3-2) (RRS), the comprehensive detection of genetically modified component in foodstuffs is of significant interest, but few protein-based approaches have been found useful in processed foods. In this report, the combination of quantitative PCR (qPCR) and western blot was used to detect cp4-epsps gene and its protein product in different RRS plant tissues and commercial soy-containing foodstuffs. The foods included those of plant origin produced by different processing procedures and also some products containing both meat and plant protein concentrates. The validity of the 2 methods was confirmed first. We also showed that the CP4-EPSPS protein existed in different RRS plant tissues. In certain cases, the results from the western blot and the qPCR were not consistent. To be specific, at least 2 degraded fragments of CP4-EPSPS protein (35.5 and 24.6 kDa) were observed. For dried bean curd crust and deep-fried bean curd, a degraded protein fragment with the size of 24.6 kDa appeared, while cp4-epsps gene could not be traced by qPCR. In contrast, we found a signal of cp4-epsps DNA in 3 foodstuffs, including soy-containing ham cutlet product, meat ball, and sausage by qPCR, while CP4-EPSPS protein could not be detected by western blot in such samples. Our study therefore concluded that the combination of DNA- and protein-based methods would compensate each other, thus resulting in a more comprehensive detection from nucleic acid and protein levels. PrACTICAL APPLICATION: The combination of quantitative PCR (qPCR) and western blot was used to detect cp4-epsps gene and its protein product in different Roundup Ready soy (event 40-3-2) plant tissues and commercial soy-containing foodstuffs. The foods included those of plant origin produced by different processing procedures and also some products containing a combination of both meat and plant protein concentrates. This study indicated that the combination of DNA- and protein-based methods would supplement each other for genetically modified detection from nucleic acid and protein levels. Accordingly, qPCR and western blot could be used in CP4-EPSPS detection in a wide variety of soy-related foodstuffs.     

Ultrasound based glass fragments detection in glass containers filled with beverages using neural networks and short time Fourier transform

Glass fragments may accidentally make their ways to glass juice bottles, which has been a serious concern of beverage manufacturers. Using ultrasound to detect these fragments in the bottle poses a challenging task for signal processing and classification. When glass fragments settle down on the bottom or are sticked to the wall of a bottle, ultrasound signals returned from the fragments will superimpose themselves onto the echoes from the inner surface of the bottle. This superposition makes it impossible to distinguish the signals of bottles with fragment(s) from those without fragment(s) by commonly used methods such as time gating and spectrum analysis. A method is developed by combining radial basis function neural networks (RBF-NN) with short time Fourier transform (STFT) for ultrasound signal classification to detect glass fragments behind glass walls. The STFT algorithm was used to extract signal features while the RBF-NN was trained using the features to distinguish signals of bottles in presence from those in absence of glass fragments. Successful classification rate of 95% was achieved by this method.     

Drop coating deposition Raman (DCDR) for microcystin-LR identification and quantitation

A drop coating deposition Raman (DCDR) method was developed for the analysis of 2-200 ng samples of microcystin-LR (MC-LR), a ubiquitous and deadly hepatotoxin secreted by cyanobacteria. Solid phase extraction (SPE) of the toxin from a water sample enabled identification of MC-LR at 5 μg/L to 100 mg/L concentrations, and the collected results suggest lower detection limits can be readily attained following DCDR substrate modification. The DCDR process was applied to aqueous sample volumes of 0.5-20 μL that generated sample deposits from which MC-LR Raman spectra could be obtained within seconds. Larger volume samples were not required to improve spectral resolution. Volumes of 2 μL were ideal, producing "coffee-ring" MC-LR deposits that displayed distinct MC-LR Raman signals with high signal-to-noise within 1 s for a 200 ng sample and 300 s for a 2 ng sample. A linear correlation between Raman signal intensity and concentration was observed for 2-100 ng MC-LR samples after signal normalization. Reproducible MC-LR Raman spectra were collected from both fresh and aged samples. The presence of dissolved organic matter (DOM) did not preclude MC-LR identification in DCDR deposits of 3 μg of DOM mixed with 0.7 μg of MC-LR. Application of DCDR to environmental samples will require sample purification such as SPE before analysis, including critical cartridge wash and toxin rinsing steps. Raman based methods may one day facilitate simpler and faster sample throughput than traditional MC-LR detection methods.     

Line-scan hyperspectral imaging for real-time in-line poultry fecal detection

The ARS multispectral imaging system with three-band common aperture camera was able to inspect fecal contaminants in real-time mode during poultry processing. Recent study has demonstrated several image processing methods including binning, cuticle removal filter, median filter, and morphological analysis in real-time mode could remove most false positive errors. The ARS research groups (Beltsville, MD and Athens, GA) and their industry partner are now merging the fecal detection and systemically disease detection systems onto a common platform using a line-scan hyperspectral imaging system. This system will aid in commercialization by creating one hyperspectral imaging system with user-defined wavelengths that can be installed at different locations of the processing line to solve significant food safety problems of disease as well as contaminant detection. Thus, this research demonstrated the feasibility of line-scan hyperspectral imaging system in terms of processing speed and detection accuracy for a real-time, in-line fecal detection at current processing speed (at least 140 birds per min) of commercial poultry plant. Our preliminary results showed the real-time hyperspectral imaging system could detect small amount (about 10 mg) of fecal (duodenum, cecum, colon) and ingesta contaminants. The system performance could be improved by optimizing line lighting system especially near-infrared bands for quality images and additional spectral images to minimize false positive detection errors. The newly developed line-scan hyperspectral imaging system could improve Food Safety Inspection Service (FSIS)’s poultry safety inspection program significantly.     

粮食中脱氧雪腐镰刀菌烯醇检测方法研究进展

脱氧雪腐镰刀菌烯醇（deoxynivalenol,DON）具有免疫毒性、器官毒性、蛋白质合成抑制和致畸性。粮食在不当的储藏条件下,容易受真菌污染而产生DON,DON被人体或动物摄入后,会引起严重的健康问题。DON性质稳定,在加工过程中难以被破坏和除去,是粮食生产加工过程中的重要安全隐患。我国粮食中DON含量超标问题突出,因此,准确、高效的DON检测方法对保障粮食安全,保证人体安全健康至关重要。该研究总结了近年来粮食中DON的主要检测方法,主要包括薄层色谱法、高效液相色谱-质谱法、酶联免疫法、侧流免疫层析法、光谱法、电化学法和表面等离子共振法等。通过探讨这些检测方法的优缺点,对各种方法进行了对比和总结,并对DON检测方法的发展趋势进行展望,为开发新型的检测方法提供理论支持,有利于推动准确快速检测方法在粮食安全检测中的应用。     

Measures of similarity and detection of miniature foreign bodies in packaged foods

Foreign bodies (FB) or particles submersed in food containers constitute a hazard and quality assurance issue for many food manufacturers. Ultrasound has demonstrated potential for detecting relatively large FBs in packaged foods. In the case of miniature FBs, the ultrasound signal goes through minimal phase and amplitude change, and as a result, small FBs may end up undetected. Similarity measures were used to capture the minute changes of the ultrasound signals during FB detection. Three measures in the investigation were Minkowski, Chebychev, and Cityblock metrics. The sensitivity of the three measures was evaluated in capturing minute signal changes with numerical signals, whose changes are quantitatively controlled. The experiments were conducted to detect small steel particles in a glass container. The Minkowski metric showed numerically and experimentally better FB detection capabilities. Two signal alignment algorithms were introduced to minimize the impact of signal misalignment on similarity analysis.     

基于超微弱发光技术检测辐照食品的研究

基于超微弱发光检测技术,研究即食食品(麦片,藕粉)经0～12kGy剂量辐照后光子信号的变化,并探讨超微弱发光用于鉴定即食辐照食品的判定方法。试验结果表明:两种即食食品辐照前后的超微弱光子计数有明显的区别,光子计数与辐照剂量呈正相关,检测阈值可低至0.3kGy。当添加检测液后的最大光子数为本底的15倍以上时,可判定为该样品经过辐照处理。     

Electron Spin Resonance Analyses of Grinding- and Radiation-Induced Signals in Raw and Refined Sugars A Comparative Study

Irradiated food containing crystalline sugar may be identified using the electron spin resonance spectroscopy (ESR) in accordance with the European standard EN 13708 2001. The method is based upon the detection of sugar radicals induced by irradiation giving a typical dose-dependent spectrum. Grinding, a common industrial process, can also produce ESR signals. In this study, the grinding-induced ESR signals were investigated for their dependence on sugar purity, grinding time, particle size, and grinding method. The results were compared with radiation-induced ESR signals. The mechanical grinding, depending mainly on grinding time, provided clear signals comparable to radiation-induced signals. The specific ESR signal corresponding to sugar radical appeared at 1 min of mechanical grinding which became clearer with the increase in grinding time and sample purity. All sugar samples upon 6 min of mechanical grinding showed comparable results to ≥10 Gy-irradiated samples. Similar results with negligible differences were found using samples of different origins. The results elaborated the detection limits of sugar containing irradiated food based on ESR analysis.     

纱线信号时频分析方法比较

阐述了一种新的时频分析方法——基于Hilbert-Huang变换的Hilbert时频谱分析,并将其应用到纱线信号分析中。以毛条信号为例,将短时Fourier变换、小波分析和Hilbert谱分析方法进行比较,指出Hilbert谱分析能对信号的时频分布做出比短时Fourier变换和小波分析更为精确的描述,从而能更准确地揭示纱线信号中能量在时域和频域同时变化的过程。通过对纱线信号进行时频分析,可以得到每个瞬间的频率变化,进而对其进行在线谱分析,可以实时监测工艺及设备状况的变化,及时发现生产过程中的异常。