Vein indwelling needle online tip defect detection scheme

Time:2020-12-18 Author: hztest

In 1962, the German company Braunule invented the first indwelling needle "Braunule". Because the use of indentation needle can reduce the pain caused by repeated venous puncture in sick children, and then reduce the fear of injection, which is convenient for clinical medication, especially for emergency and critically ill patients. The use of indwelling needles can greatly reduce the pressure of doctors, so intravenous indwelling needles have been widely used in clinic in recent years.

The venous indwelling needle, also known as the venous trocar, consists of a flexible catheter/cannula that can be indwelled in the blood vessel, and a stainless steel puncture guide needle core. When used, the catheter and the needle core are punctured into the blood vessel. When the catheter has fully entered the blood vessel, the needle core is withdrawn and only the soft catheter is indpended in the blood vessel for infusion therapy. Good quality needle tip can reduce the pain of children and relieve the anxiety of parents, which is the premise of successful use and promotion of indentation needle.

Due to the external catheter, the diameter of the design needle is very thin, generally about 0.45mm, its edge surface is enlarged to see the structure is more complex, there is an oval hole in the middle, and the edge surface presents a certain slope. The defects detected generally include whether the tip is sharp, dull, burr, whether the edge surface is dirty, and whether the tip is crooked.

Since the indenture needle is in a state of high-speed motion on the production line, in order to take a clear image of the needle tip in real time, in addition to ensuring a clear image of the edge surface, the edge and the background should have a clear contrast and present a clear outline.

Zhejiang Huazhou Intelligent Equipment Co., Ltd. uses its own research and development of PLS series of far-center parallel light source to provide a good solution for the tip detection. This series of parallel light source uses a telecentric lens, and its lens is specially precision cold machined to ensure that the light emitted by the lamp bead is changed into a nearly parallel beam through the telecentric lens. Because of the cylindrical shape of the needle, the edge imaging has no obvious boundary, and it is difficult to highlight the clear outline of the blade surface and the needle in the ordinary bright field or dark field lighting method. PLS parallel light source with telecentric lens can eliminate the phenomenon of edge blur caused by light source diffusion, obtain clear and sharp images, and greatly improve the measurement accuracy.

In terms of algorithms, the VisionTech platform is used with a high frame rate GigE interface industrial camera with a bilateral telecentric lens.

The software performs image binarization, Gaussian filtering and morphological processing to ensure the contrast of the edge surface and tip edge images. Due to the high-speed movement of the product on the production line, the software algorithm overcomes the adverse effects of product jitter, equipment vibration and light changes, and the software interface design is as simple as possible to achieve operation and design, which is convenient for on-site workers to maintain and switch products. It greatly saves the time of on-site commissioning and maintenance and allows customers to adjust the size of defects in real time to meet the inspection needs of different products.

After the test is completed, the software can also generate statistical reports according to customer needs to quickly calculate the production situation of the day and the distribution curve of various defective products, so as to facilitate customers to improve the production process for different defects and improve product quality in the future.

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