Machine Vision Flashcards
In an industrial context, what do we use Machine Vision for?
- Visual Inspection
- Counting
- Measurement
- Locating
- Decoding
What are some of the key factors to consider when selecting a lighting system?
- Target characteristics
- Inspection task
- Colour (or grey tone)
- Feeding speed
- Flash of continuous illumination
- Ambient conditions
What are the two main catagories of light orientations we use for machine vision?
Backlighting and Top Lighting
What are the features of Backlighting?
- Great Contrast
- Contour Projection Independent of the Object Surface
- Suitable for Dimension Measurement
What are the features of Top Lighting?
- Material Properties
- Surface Effect Image
- Sensitive to External Light
What are the five main catagories of Top Lighting used?
- Full / Partial Bright Field
- Dark Field
- Diffuse Dome
- Axial Diffuse
- Flat Diffuse
If each primary colour intensity is discretized with a byte (8 bits), then how many colours can an RGB camera detect?
(2^8)^3 = 16777216
What are the two types of Lenses?
Telecentric and Endocentric (Conventional)
What are the main features of a Telecentric Lens?
- Object size independent of distance
- No distortion, no dependent on external light
- Big lens, very expensive
What are the main features of a Endocentric Lens?
- Cheap and small
- Object size depends on the distance
- Distortions
What is the formula of the working distance of a lens?
g = f (G/B + 1)
f is the focal length
g is the working distance
G is the field view
B is the sensor size
What is the formula for the resolution?
Resolution = Length of part / Number of Pixels
What is the typical accuracy of a lens?
+5 resolution or -5 resolution
What is a Monadic Operation for Image Processing?
An operation where the output image is the same size as the input image, and the same function is applied to all pixels
What is a Diadic Operation for Image Processing?
Two images are combined into a single image, and we can use binary arithmetic operations
