Tag
color-spaces
2 posts · browse all tags
Fundamentals The Camera Response Curve: Why Your JPEG Is Not Proportional to Light
Raw counts are proportional to the light that arrived. The developed file is not: on the same six neutral patches, a linear ratio of 42 to 1 comes out as 187 against 14 code values. Measured here — a single exponent misses by 9.6 code values, because the curve is a gamma with a contrast S stacked on it.
computer-visionimage-processingsensorscolor-spaces
Read more → 
Fundamentals Colour Spaces: Choosing Axes You Can Threshold
Lesson 4 of The Image as Data. A colour space is a choice of axes for the same three numbers, and the choice is what makes a question easy or impossible. Worked on one measured chart patch: RGB (149.8, 58.3, 34.0) becomes luma 82.8, hue 12 degrees stored as 6, and a Lab triple — plus the five-line red detector that is brittle in RGB and robust in HSV.
computer-visionimage-processingopencvcolor-spaces
Read more →