1. Machine Vision Applications Case Study No. 4 Cake Decoration Patterns

2. The Product Manufacturing –Continuous process –Plan of factory floor –Multi-lane production line –How decoration is applied –Cutting cake into fingers –Packing Need for inspection –Many potential inspection points –Many places where product can be spoiled Disposal and re-use of waste product

3. Typical Decoration Patterns

4. Lighting, Optics and Viewing Continuous flow, multi-line, coloured product –Colour line-scan camera, or cameras Linear light source –Fluorescent tube - needs HF driver –Fibre optics - expensive –LEDs - good stability and colour control Turbo-charging inappropriate Chain conveyor - poor back-ground –Angled lighting to improve back-ground (Method 128) Using array camera –Strobing - health and safety problems –Problem of locating defects

5. Preprocessing Fine colour discrimination may be needed –E.g. yellow on yellow –Optical filters –Use of fluorescence to improve contrast Surface rough & uneven for range mapping Crack detection algorithm Thinning –Analysis is independent of line thickness

6. Measurements Euler number Zero crossing count Template matching Grass-fire transform and histogram analysis Morphology –Checking for line thickness –Shaped SEs to detect Crossing points Lines at given orientation Islands Sloppy template aligned by morphology

7. Improving Speed Buy a faster computer –“Wait until next year” Dedicated hardware Change the IP algorithm –Use an approximation to the desired algorithm –Reformulate the algorithm to run faster Local area histogram equalisation SKIPSM

8. Separated Kernal Image Processing by (Finite) State Machine (SKIPSM) Reference: B. G. Batchelor & F. M. Waltz, “Intelligent Machine Vision: Techniques, Implementation & Applications”, Springer- Verlag, London, 2001, ISBN 3-540-76224-8. URL: http://bruce.cs.cf.ac.uk/bruce/Chapter5.pdf Basic concept –Row machine –Column machine Speed improvement Lesson in scientific discovery

9. SKIPSM