Posted to News on 6th Oct 2010, 21:40
Four-CCD linescan camera detects NIR, red, blue and green
Stemmer Imaging UK can now offer the novel JAI LQ-200CL four-CCD colour linescan camera, which uses the prism basis. Already well known for three-CCD colour linescan cameras such as the CV-L108CL, JAI has added a fourth channel to provide NIR (near infrared) imaging. Capable of simultaneous imaging of NIR, red, blue and green light through four independent channels but the same optical path, the innovative LQ-200CL enables identification of an even wider set of defects (including sub-surface imaging) on inspected objects. It can be used in a host of different industries.
NIR imaging allows features below the surface of an object to be viewed, thereby providing different information to the RGB channels and revealing imperfections that the human eye cannot see. Linescan applications include: fruit and vegetable sorting, food inspection, web inspection (wood, textile, paper, glass), tiles inspection, 2D and 3D print inspection, surface inspection of flat panels/displays and PCB inspection.
The camera's innovative dichroic prism-block technology splits the incoming light into the four non-overlapping spectral bands and directs them onto four separate CCD sensors with perfect pixel to pixel alignment, thereby ensuring that the R, G, B and NIR pixels image exactly the same point on the object at all times. This produces high-quality and perfectly aligned line scan images that are independent of the viewing angle to the inspected object, independent of variations on conveyor belt speed and independent of whether the object has a wavy or curved texture. This precise image alignment and colour registration makes inspection systems featuring these cameras faster and easier for end-users to setup, calibrate and maintain.
Each of the four CCD sensors provides 2048 linear pixels with a pixel size of 14 x 14um square. The camera runs at a maximum scan rate of 19048 lines per second with a 40MHz pixel clock, delivering a high signal-to-noise ratio of 58dB. Built-in pre-processing functions include flat-field correction and gamma/gain correction, which, together with the electronic shutter, can be set individually for the red, blue, green and NIR channels. The gamma/gain correction function also allows full advantage to be taken of the sensors' dynamic range to optimise the image.
