Pixels Flashcards
How does imaging work?
The image from the lens is focused on a CCD, a light sensitive microchip or charge coupled device, with millions of pixels.
Depending on the charge, the pixel could be numbered from 0 to 255.
What is binary?
Binary is on or off, with 1=on, and 0=off. If one pixel records on or off, depending on light intensity and charge, only one memory location is required.
How many bits are needed for 256 alternatives?
The number of bits for 256 alternatives is 8, and this is equal to one byte.
What’s the formula relating number of alternatives to bits?
N = 2^b
What’s resolution and what’s its formula?
Resolution = width represented in image/pixels across
Resolution is the smallest detail that can be distinguished.
What’s the formula for image information?
Information = bits per pixel * number of pixels.
How can brightness of an image change?
Increase the number across each pixel until the brightest reach 255.
How is noise reduction achieved?
Noise can be removed with mean/median smoothing.
What is edge detection?
Edges are removed by taking away the mean value of a pixel’s neighbours from each pixel, removing areas of uniform brightness where gradient changes abruptly.
How do you increase contrast?
Increase the range, from 75-150 turn 75 into 0, (black), and 150 to 255, (white).
