In the HSV colour space, the complementary colour of green is:

- blue
magenta

- cyan
- yellow

In OpenCV, if Y indexes lines, X columns and C channels, the right nesting >of loops is

- X inside Y inside C
- C inside Y inside X
- Y inside X inside C
C inside X inside Y

An image which is under-exposed will have a histogram that

- has a peak at high grey-level values
- has a peak towards the middle
has a peak at low grey-level values

- has no significant peaks

What is contrast stretching?

expanding the available grey levels to fill the range used for displaying images

- the range of grey level values
- the standard deviation
- re-scaling the data to a given mean and standard deviation

With additive colours, yellow is a mixture of

- cyan and red
- red and cyan
- blue and green
red and green

After contrast-stretching, an over-exposed image which has only a few grey levels occupied will have a histogram that

- has a concentration of large values near high grey-level values
tends to show small spikes across the entire range of grey levels

- has a nice peak of grey levels in its middle region
- has all grey-level bins roughly equally occupied

OpenCV was initially developed in

- Australia
- UK
Russia

- USA

What is plotted along the abscissa (x-axis) of a histogram?

grey level

- standard deviation
- mean value
- number of occurrences

For an image of unsigned bytes, how can it be contrast-reversed?

- subtract each pixel from 127
- negate each pixel
- subtract 255 from each pixel
subtract each pixel from 255

Histogram equalization involves:

- using the histogram as a look-up table
- using the reciprocal of the histogram as a look-up table
using the cumulative histogram as a look-up table

- using the inverse of the histogram as a look-up table