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Electronic Imaging Fundamentals: Pressure Die Castings. August 2008. “..any sufficiently advanced technology is indistinguishable from magic.” Arthur C. Clark.
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Electronic Imaging Fundamentals: Pressure Die Castings August2008 “..any sufficiently advanced technology is indistinguishable from magic.” Arthur C. Clark
Background:Quality control is of major importance in the pressure die casting industry. Inspection of the item by human inspectors prone to short and long term variations. An automated casting inspection system using cameras is proposed.
Requirement:Provide image analysis technology linked to a camera to measure size / thickness / angle / shape and other parameters as required. REJECT when measurement obtained is outside SPEC, allowing casting 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) Resolution(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
Thresholding an Image Select appropriate morphometric characteristics Identify regions of interest to analyse Mask regions Colour Size Shape Intensity
DATA 20080814_18-25- 0.514 20080814_18-25- 0.514 20080814_18-25- 0.523 20080814_18-24- 0.862 20080814_18-24- 0.504 20080814_18-24- 0.407 20080814_18-24- 0.162 20080814_18-23- 1.17 20080814_18-21- 0.281 20080814_18-21- 1.806 20080814_18-21- 0.169 20080814_18-20- 0.626 20080814_18-20- 0.969 20080814_18-19- 1.121 20080814_18-18- 0.957 Recorded Rejected
NEXT STEP: Consulting@ R 7 500.00 to explore: - CCTV vs DIGITAL (accuracy) - Measurement process (11 measurements) - Image setup - Equipment required - Input Trigger / rejection - Image / data storage