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Electronic Imaging Fundamentals: BISCUITS. July 2008. “..any sufficiently advanced technology is indistinguishable from magic.” Arthur C. Clark.
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Electronic Imaging Fundamentals: BISCUITS July 2008 “..any sufficiently advanced technology is indistinguishable from magic.” Arthur C. Clark
Background:Quality control is of major importance in the food industry. Inspection of the biscuit by human inspectors prone to short and long term variations. An automated biscuit inspection system using cameras is proposed.
Requirement:Provide image analysis technology linked to a camera to measure biscuit size / thickness / colour / shape and filling. ALARM when measurement obtained is outside SPEC, allowing biscuit to be rejected.
Why do Image Analysis? Better Definition of Contrasting Areas Improved Precision/Accuracy in Measurements Reproducibility of Results Higher Throughput than Manual Methods
A Word About Our Eyes Eyes are very good contrast adjusters, but not good for distinguishing subtle variations in color Eyes can discern about 30 continuous levels of gray or color in a field of view Eyes are not good judges of distance Eyes cannot accurately reproduce measurements
Electronic Imaging Fundamentals Acquire Process Identify Analyze Report
Acquiring the Image Arguably, the most important aspect of all Proper setup of imaging apparatus is vital Obtain maximum contrast and dynamic range Reduce “noise” and other unwanted artifacts Uniform lighting (light) Product presentation (right way up) Speed (CCTV VS DIGITAL)
Local I/Os: • Trigger input • Results output Illumination control Illumination Acquire Image sensor Pre-processing Digitizing (Lens Iris Video) Cat-5e Ethernet cable up to 100 m Image Processing In PC Lens Power Interface Timing PLC
Calibration Size (length, width) Colour (filling; biscuit) Combinations of the above
Site visit:2 cameras per lane1 for filling, 1 for breakages10-15 biscuits per second10 cm working areaConcern of cream on lens?
Thresholding an Image Select appropriate morphometric characteristics Identify regions of interest to analyse Mask regions Colour Size Shape Intensity
Damaged Biscuits Recorded Rejected % allowed % to alarm % to turn off machine
NEXT STEP: • 2 Options • Option 1: Order System • 3 Payment Options: • Capital (+- R 45 000.00 per line) • Rental per Month (+-R 8 000.00) • Cost per Biscuit (0.08 c) • Option 2: Consulting • @ R 7 500.00 to prove above costs