Line Scan Products
Line scan products are invaluable tools for test and inspection in industry and amongst the most effective vision solutions available to manufacturers. Line scan technology is ideal when high-resolution pictures are required as part of a vision solution when large objects must be photographed, and when image capture needs to be done at high speeds.
The technology is used in a number of different industries including pharmaceuticals and food and beverage. For instance, it can be used to:
- Virtually “unwrap” cylindrical objects for inspection. After unwrapping, other tools can then be used for fill-level inspections, label-application inspections, date and lot code reading, safety seal inspections, and to ensure size uniformity of objects.
- Meet high-resolution inspection requirements. High-resolution inspection is critical in most tech-oriented industries. You can use line scan vision cameras to inspect and identify large products and also to perform code and text reading.
- Easily inspect objects in continuous motion. This functionality is especially appealing to consumer and food products manufacturers. It allows you to perform inspections on high-speed packaging lines and conveyors and easily verify codes and text.
Additionally, line scan technology is commonly used to inspect continuous web applications for defects, including paper and textile products that are produced in long rolls. It is a standard tool for medical diagnostics and is used for inspection of solar cells, flat panel displays, printed circuit boards, silicon wafers, and so on. It is also used to capture images of “free-falling products,” ranging from postal sorting to molten glass, and for satellite imaging and scanning of surface topography.
How Line Scan Products Work
Unlike normal frame cameras that take two-dimensional images, line scan cameras have one single row of pixels that is used to build the image, either by moving the object or the camera at right angles to the pixels.
Line scan sensors have one line of pixels or more. Individual pixels accumulate photoelectric charges that correspond to the light on the pixel from the imaged object. The charges from the line of pixels are transmitted to a readout register that amplifies, corrects, and digitizes the pixels. This is rapidly repeated for each line of pixels.
Pixel data from line scan cameras is then transferred to a vision processor or “frame grabber” with an acquisition interface that receives data in various formats. It is here that the pixel values are aggregated into a frame that can be processed to read text, check for defects, or complete other machine vision tasks.
Because camera exposure is slower than pixel readout, line scan cameras have the ability to expose new images while data from previous images is still being transferred.
Another benefit is that line scan cameras need simple lighting to illuminate the objects being imaged – typically a “line light” from LEDs that provides high-intensity lighting for short exposure times. Line lights are normally used for back-lighting when checking for pinhole defects, or positioned above the object or product when checking for surface defects.
Time delay and integration (TDI) camera move lines of pixels electronically and provide longer exposure times.
Area Scan Cameras
Unlike line scan cameras that have specialized applications, area scan cameras are considered general purpose. They contain a grid of pixels (rather than a line) that captures images. They are also easier to set up and align. Area scan cameras work particularly well for imaging stationary objects.
The resolution of area scan cameras is fixed, and they can record a specific area very quickly. They offer greater flexibility than line scan cameras as single images can be broken into multiple areas of interest when looking for specific objects, rather than processing the whole image at one time.
Area and Line Scan Products from MESH
MESH Automation offers both line scan and area scan cameras that offer different advantages.
Contact us today to discuss how line scan or area scan cameras can help your business optimize productivity, increase efficiency and potentially cut costs.