# Near Infrared Illumination Optimization for Vein Detection: Hardware and Software Approaches
## 1 Introduction  
NIR imaging is one of the emerging technologies to facilitate vein detection. It is especially beneficial for the peripheral IV catheter to gain access to a vein. Although the reviewed devices had demonstrated usefulness for peripheral veins visualization, the other evaluated factors were less definite to preclude any general conclusions about their overall performance. The utilization of NIR technology is a novel technique and started to receive research interest since 2010. However, the availability of these commercial devices related to image acquisition techniques remained an unsolved issue due to the deficiency of the performance and the high costs of the devices. Thus, it is crucial to study the essential parameters for enhancing the image acquisition approach to obtain a higher-quality vein image. This paper presents the proposed enhancement of the vein visualizing system. Four essential parameters were investigated: evaluation of NIR peak wavelength, LEDs arrangement for light illuminationpurposes, the effect of the diffuser and the number of illumination LEDs. This research also focuses on developing a highly affordable, integrated, portable vein visualization device that uses low-cost commercial off-the-shelf electronic components. Venepuncture and intravenous cannulation are among the most common medical procedures that were performed on patients [1]. In a human blood vessel, it contains information for health monitoring and possible diseases that can be detected [2]. However, finding a good visualization of vein structures [3] is often difficult. Thus, the nurse has no choice but to perform based on their anatomical knowledge and experience [3]. This sometimes leads to some errors, which may cause direct or indirect harm to the patient. Infrared radiation is a good preference since it can penetrate up to several centimeters into tissues [1]. The maximum absorption range was found in the near-infrared spectrum (700-900 nm) for NIR-I, as discussed by [PERSON], 2016 [4]. While [PERSON] and [PERSON], 2017, revealed that near-infrared radiation (NIR) is strongly absorbed by both veins and arteries using a narrow radiation window of 750-950 nm, water has a reduced influence on the scanning. Veins strongly absorb NIR radiation based on a narrow optical window. Different wavelengths show different behavior of haemoglobin together with water when illuminated with NIR radiation. Therefore, the optical window can be chosen between 700 and 950 nm. Infrared radiation is absorbed by haemoglobin in the blood vessels while the surrounding tissues other than the blood vessels do not absorb infrared radiation but reflect it [5]. When capturing an image of the blood vessels, it will appear darker than the other parts as they absorb infrared light [2]. Infrared radiation is capable of capturing the superficial vein inside the human body [6]. [PERSON] and [PERSON], 2010, discussed a vein pattern extraction algorithm for biometric identification. Using low-quality sensors, they studied image acquisition and pattern detection techniques for veins and proposed a technique to detect tissue patterns using thermal (IR) imaging. However, the research is much more complicated and requires costly equipment. There is another type of device that uses far-infrared (FIR) light, where a thermal camera is used to obtain images of procedures ranging from visualizing vein structures to performing segmentation; however, it still encounters the disadvantage of high-cost equipment [3]. Other vein visualization devices use penetration methods of NIR light. Nonetheless, current devices have drawbacks, whereby they are big and inconvenient to use during venepuncture [3]. In the latest studies, a vein camera mobile application to obtain NIR images was designed by [PERSON] and [PERSON], 2019 [7]. This was followed by the design of a low-cost system to detect the veins in the palm by [PERSON], 2020 [8]. Further quantitative and experimental studies are needed to achieve the optimal results of the vein image.