Histogram equalization involves:

using the cumulative histogram as a look-up table

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

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

- negate each pixel
subtract each pixel from 255

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

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

- has a peak at high grey-level values
- has no significant peaks
has a peak at low grey-level values

- has a peak towards the middle

OpenCV was initially developed in

- USA
Russia

- Australia
- UK

What is contrast stretching?

- the range of grey level values
- the standard deviation
expanding the available grey levels to fill the range used for displaying images

- re-scaling the data to a given mean and standard deviation

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

- blue
- cyan
- yellow
magenta

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

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

- C inside Y inside X

With additive colours, yellow is a mixture of

- blue and green
red and green

- red and cyan
- cyan and red

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
- has all grey-level bins roughly equally occupied
- has a nice peak of grey levels in its middle region
tends to show small spikes across the entire range of grey levels

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

grey level

- number of occurrences
- mean value
- standard deviation