Chapter 4 Flashcards
What scene factors influence image quality?
The object and the amount of light exposure
What camera factors influence image quality?
The sensor characteristics/sensitivity, aperture, exposure time and frame rate (video)
What is image resolution?
The number of pixels recorded in an image
What is the frame rate of a video?
The number of images recorded per second
What is the aspect ratio?
The ratio of horizontal dimensions to vertical dimensions
What three elements are on the exposure triangle, and greatly impact image quality?
ISO, aperture and exposure time
What is ISO?
A measure of camera sensitivity.
Slow film has low sensitivity and fast film has a high sensitivity
What is aperture?
The aperture is a mechanical device that can open or close and increase or decrease the amount of light coming into the lens
To reduce blurry images, what should be done?
Reduce the amount of exposure time.
For capturing human movement, how should the iso, shutter speed (exposure) and aperture be manipulated?
High shutter speed (reduce blurring), closed aperture (increasing the depth of field) and lower ISO (reducing ‘grain’/‘noise’)
What are the characteristics of a scientific experiment?
Independent, respondent and controlled variables
What are the types of errors that can occur from improperly positioned cameras?
Parallax error
Perspective error
Lens distortion error
What is parallax error?
Parallax error occurs when the sensor is not parallel to the motion (perpendicular to the camera).
What is the FOV determined by?
The distance between the lens and the sensor - closer = larger FOV, farther = smaller FOV
What is perspective error?
When near objects appear larger and far objects appear smaller.
What is lens distortion error?
Has to do with irregularities in the lens shape, with distortion being greatest towards the edges of the lens.
How can you mitigate lens distortion error?
By aligning the optical axis (centre of lens) with the movement of interest.
What is digitization?
Assigning Cartesian coordinates to important landmarks.
