A line scan camera has a single line of pixels that image across an object. To build up a two-dimensional image of the object, either the camera or object is moved perpendicular to the line of pixels. This might seem like a complicated way to image an object compared with “frame cameras” that take two-dimensional images (a “frame”). However, when the object is large, continuously moving, or the task needs perfect or high-resolution imaging, a line scan camera is often a much better choice than a frame camera.
When to Use Line Scan Technology Line scan technology is ideally suited to applications in which large, high-resolution, or high-speed image capture is needed, such as in a continuous web application—paper, textiles, metal, or glass tape, for example—or for railway and road inspection, or for satellite imaging or surface topography scanning.
Line scan technology is the method of choice in continuous web applications. Let’s say at a production line for a plastic film that is 12 feet wide and moves at 350 linear feet per minute, we are looking for small defects, such as holes, dirt or contaminants. Attempting this level of inspection with an area scan camera is very challenging due to the wide area and high speed of the web. Doing this by human vision inspection is impossible. Defects are classified based on size range, such as from 50 to 100 microns or 200 microns, and contrast type. A bright object might be a hole and a dark object might be a contaminant. For this level of detail and web width, six Gigabit Ethernet 2048-pixel line scan cameras are needed. Backlight is used, so a line light shining through the web and into the camera.
Setting up multiple line scan camera and image acquisition is a challenging
Qualitas has developed a multi-line scan system which allows to easily set up multiple line scan cameras in an array. This will be useful where you either need to image a large web width with high precision and clarity.
Our patent-pending solution consists of 2 or more line scan cameras along with Windows-based calibration software that allows easy calibration of cameras using a wizard-based application.
Each camera can be aligned with the others with respect to roll, pitch, and yaw using this application. Our indigenous solution also includes calibration tiles for multi-line scan configuration and measurement applications.