There are two potential ways to interpret the word "contrast" here, and I confused the two in lecture. So let me clarify!
I mentioned in lecture today that contrast can be defined as the ratio between the brightest pixel and darkest pixel. This contrast ratio is used to characterize displays or TVs, where a higher contrast ratio is better (blacks are darker and whites are brighter).
In this slide though, the word "contrast" is defined slightly differently. It refers to the difference between the brightest and darkest pixel. When multiplying the range by a factor 2, we raise the contrast (but it doesn't actually affect the contrast ratio). Similarly, if we divide by 2, we lower the contrast (but not the contrast ratio).
To distinguish the two, we'll use the term "contrast ratio" for the ratio of brightest/darkest pixels, and "contrast" for the difference between brightest/darkest pixels.
There are two potential ways to interpret the word "contrast" here, and I confused the two in lecture. So let me clarify!
I mentioned in lecture today that contrast can be defined as the ratio between the brightest pixel and darkest pixel. This contrast ratio is used to characterize displays or TVs, where a higher contrast ratio is better (blacks are darker and whites are brighter).
In this slide though, the word "contrast" is defined slightly differently. It refers to the difference between the brightest and darkest pixel. When multiplying the range by a factor 2, we raise the contrast (but it doesn't actually affect the contrast ratio). Similarly, if we divide by 2, we lower the contrast (but not the contrast ratio).
To distinguish the two, we'll use the term "contrast ratio" for the ratio of brightest/darkest pixels, and "contrast" for the difference between brightest/darkest pixels.