Camera Images Flashcards
Computer Vision
How does the Pinhole Camera principle:
light enters a dark box through a small hole and creates an inverted image on the wall opposite the hole
- Image through a lens:
- all the rays of light that came from an object in direction to the lens, converge
- focal distance is the distance the image converges in the other side of the lens
- focal plane is where all the points that verify this fact are
- Geometry:
- lines project lines
- lines in 3d project to lines in 2d
- distances and angles are not preserved
- Image sensors: What are some considerations to have?
speed, resolution, cost, signal/noise ratio
- What characterize CCD?
- higher dynamic range, high uniformity, lower noise
- and what characterize CMOS?
- lower voltage, higher speed, lower system complexity
What is CMOS?
Complementary metal–oxide–semiconductor
- How is a digital image represented?
by a rectangular matrix of scalar vectors
What is necessary to convert an image (f(x;y)) into a digital image?
It is necessary to perform spatial sampling and amplitude quantization
What is CCD?
Charge-coupled device
What is Digitalization?
- continuous light distribution is spatially sampled
- still image created by time sampling the discrete distribution
- resulting values are quantized to a finite set of numerical values
- Sampling means digitizing the coordinate values
- Quantization means digitizing the amplitude values
What types of -Images are there?
- Black and white (binary) - f(i,j) e {0,1}
- Grayscale - f(i,j) e {0,…,(2^b)-1}
- Color-indexed - f(i,j) e {0,…,(2^b)-1} -> I e {0,…,(2^b’)-1}^3
- Color (RGB) - f(i,j) e {0,…,(2^b)-1}^3
What characterize Color-index images?
they save memory, storage space and transmission time
What does he process of converting analog video into digital video require?
Spatial and temporal sampling, besides amplitude quantization
What are the two Color production systems?
-Additive (monitors) - RGB - Together we have white
-Subtractive (printers) - CMY - Together we have black
