Machine Vision for Blister Pack Inspection
When it comes to the different machine vision applications our setups are used for, one of the more interesting ones is blister inspections with computer vision. Clients use our hardware to inspect the quality of the package, improve quality control and to identify any damage to the surface, which would brand the package as a defect. Naturally, these kinds of inspections require quite a bit of detail and a specific combination of products.
Therefore, this article is written to save time and to avoid potential mistakes when choosing the correct items for the application. Furthermore, this article is based on a past situation that corresponds to the topic, and it will include the advice provided by one of VA Imaging experts both from the side of hardware and software. Furthermore, links will be connected to product titles, whereby clicking them, a person will be able to instantly see the product prices and various other information regarding the product.
In this case, the client who was working on the application wanted to develop an inspection system for capturing images of blisters and inspecting them for any damage. By identifying the damaged blisters using our hardware the customer was able to increase the overall efficiency of the process and minimize the chances of error.
Table of contents
Selecting the Most Optimal Machine Vision Camera
Firstly, when creating an optimal setup, it is essential to choose an industrial machine vision camera, which fits the specifications of the situation at hand. In this scenario, the customer was advised to use the 26MP USB3 camera 'ME2P-2621-15U3C' camera. This product is a 26-megapixel camera, which is equipped with a Gpixel GMAX0505 sensor, a Global Shutter, records color data and has a framerate of 15fps. Furthermore, the customer mentioned that the distance from the camera to the PC is around 3 meters and he emphasized a preference for USB3 interface. Therefore, apart from the customer’s request for a specific interface, our recommendations regarding interfaces are usually based on the distance between the camera and the PC. Also, USB3 interface cameras are focused on high resolution and high speed.
Moreover, the customer specified that there is a need to record color data, therefore, naturally, the customer was proposed to use a color camera. Also, the blisters are inspected while a conveyor is moving them and that is why a Global Shutter was essential for this application.
Furthermore, a very important factor in this situation was the resolution of the camera. The customer mentioned that the blister package inspected has the size of 165x165mm, which in this case was also viewed as the FOV and the smallest detail needed to be seen was 0.1mm. Therefore, based on this information, it was expected that the 26 megapixel camera, equipped with a Gpixel GMAX0505 sensor and a resolution of 5120x5120 pixels, would be a good fit.
Selecting an Industrial Lens for the Application
When it comes to deciding on an optimal lens that would work with the chosen camera, it is important to consider the optical size of the sensor. In this case, the GMAX0505 sensor has a 1.1 optical size. To figure out what lens would be the best fit for the setup, it is advised to use the online lens calculator. Moreover, in this situation, the needed specifications to provide the correct lens were the horizontal field of view and the working distance. Also, the camera’s resolution and the pixel size are used to identify the actual FOV of the setup (See the calculations below for reference).
Furthermore, different working distances were tried out. By doing so, it was identified that with the mentioned camera and lens at a working distance of 700mm, the actual field of view achieved would be 166.4x166.4mm.
Therefore, based on these findings and the calculations seen in the screenshot on the side, the VA-LCM-25MP-50MM-F2.4-120 lens was advised. Also, before continuing with the topic of software, it is important to mention that in this case, the customer already had a machine vision lighting solution set up.
Lens calculator
Computer Vision Software for Blister Inspection
When it comes to the software for the application, the client already had software in mind. Since VA Imaging, products are GenIcam compatible, the customer could use it with their 3rd party software. As an example, VA Imaging products can be compatible with 3rd party software like Arm Board, Cognex Vision Pro, Matlab, MvTec Halcon, Ni Labview and OpenCV. However, to program the system, it was advised to the customer to use the provided free software -the DAHENG IMAGING SDK (SOFTWARE DEVELOPMENT KIT). The SDK was used to set up the required parameters of the camera and to acquire the images. Moreover, programming languages like C++, C#/.NET and Python are supported by the SDK. Also, the software is compatible with ARM platforms, industrial PCs and runs on systems like Android, Linux and Windows.
Help with your machine vision application?
This setup was identified for a specific application – blister pack inspection. If there is a need for a solution to your application, do not hesitate to contact one of our experts. You can do this by using the form below and one of the mentioned machine vision experts will reach out to you.
