# Assessment and Feasibility Study of Lemon Ripening Using X-ray Image of Information Visualization
## 1 Introduction  
The traditional way to determine the qualities of fruit is subject to measurement using a penetrometer or the farmer's subjective experience on the flipping sounds caused by finger tapping on fruits. Fruits are classified into solid-sound fruits, hollow-sound fruits, and bad fruits. This is how people identify and discard defective products. This manual non-destructive inspection method for selecting fruit is manually intensive, and only those with significant experience able to accurately determine fruit quality. The classification accuracy of this method varies according to personal psychological states. Scientific non- destructive inspection techniques for selecting cultural products include ultrasound, magnetic resonance imaging, X-ray, and near infrared spectroscopy (NIRS), which have been developed over decades [1]. Ultrasound is those sound waves or vibrations with frequencies higher than 20 kHz, the upper limit of the human hearing range. Ultrasound is particularly suited to identifying the hollowness and quality of fruits and vegetables [2]. [PERSON] et al. used the ultrasound technology to identify the hardnessand water content of naval oranges. They found that the ultrasound signals were highly correlated to navel oranges' hardness [3]. [PERSON] and [PERSON] et al. exploit the feature of ultrasound in relation to attenuation coefficients of substances and discovered that there was a relationship between dry weights and the ripening of bell peppers and avocados [4; 5]. Magnetic resonance imaging (MRI) uses a strong magnetic field, radio waves and a computer to produce detailed images of the nucleuses in the target and make it possible to gain a deep insight into the real damages inside the agricultural product [6; 7]. [PERSON] et al. used the MRI technology to observe the ripening of tomatoes. They used MR images to observe significant changes in signal strength with tomatoes of different ripening. The ripening of tomatoes was identified based on the T2 relaxation and diffusion weighting MR images [8]. [PERSON] et al. applied the MRI technology to observe the ripening of mangos. The changes in MRI signal strength according to the ripening did not follow a regular pattern due to the differences in fruit peels. Thus, the choices of the regions of interest (ROIs) on the MR images were essential [9]. [PERSON] et al. adopted partial least squares (PLS) to analyze pomerangate MR images to retrieve information on the quality of the collected pomerangates using a non-destructive inspection method such as brix, acidity, and pH scale [10]. The wavelength range of NIRS is between 780 nm and 2500 nm. NIRS can be used to identify the characteristic substance in the target object based on the property that the energy levels of molecules and atoms of the agricultural product are different and may lead to different absorption rates due to different wavelengths. Then, combined with the characteristic spectrum database of the known substance, the composition and structure of each point can be obtained. Most functional groups within molecules, such as C-H, O-H, and N-H, of most substances have fixed vibrational absorption spectra within this range. The NIRS inspection technology for agricultural products utilizes the absorption and transform of spectrum energy to perform qualitative and quantitative analyses on the compositions of agricultural products. Currently, many efforts have been done on the applications of this technology on agricultural products such as apples, cherries, bananas, grapes, peppers, and paddy rice [11; 12; 13; 14; 15; 16; 17; 18; 19]. Since the discovery of X-rays in 1895 by Germany physicist [PERSON], photostimulable substances have been used to transform invisible light energy into visible light energy with the ionizing radiation energy produced from the three basic exposure controlling factors, kV, mA, and s. Different linear attenuation coefficients of substances and different absorption intensities of ionizing radiation can be reflected through film imaging [20].