Image J/Fiji

Question 1

Define “Segmentation” and “thresholding”

Answer 1

Segmentation is a means of separating image pixels into different subsets
Thresholding is the method of segmenting an image

Question 2

Define a bin or binning

Answer 2

A container or range that used to group data (in image analysis, pixels or pixel intensities) into intervals

Question 3

Definition of a pixel

Answer 3

Short for “picture element” - the smallest unit of an image displayed on a screen or captured by camera

Question 4

Concept of bits and bytes

Answer 4

Bit (binary digit) is the most basic unit of information in computing, either a 1 or 0, ie binary system.
8 bits = 1 byte
1kb = 1024 bytes
1mb = 1024 kbs

1024 bytes because 2^10 = 1024. ^10 because closest to 1000. Borrowed term from metric system but actually binary powers

Question 5

How does bits relate to images (eg 8-bit image)

Answer 5

Relates to concept of “bit depth” - ie amount of info stored per pixel
8-bit image = each pixel is represented by 8 bits (1 byte), ie 2^8 = 256 values.
2 types of 8-bit images: greyscale and colour
In greyscale, each pixel has an intensity value between 0 (black) and 256 (white), and shades of grey in between
In colour, each pixel represent an INDEX in a colour palette of 256 colours - actual colour depends on the palette.