System to display gamut excursion
A test and measurement device includes a graphical display that may act as an adjunct to a CIE chromaticity diagram 100 when analyzing color images. The graphical display shows indications of excursions of pixel color that are outside the boundary of a selected gamut. The graphic display may show the indications of excursions relative to one or more reference points.
1. A display for showing information from a video frame relative to a selected gamut, the selected gamut including a defined set of colors, the display comprising:
an indication of a pixel location for a pixel color in the video frame that exceeds those within the selected gamut, in which the indication of the pixel location includes constructing a line having a rotation angle indicating the pixel color and a location reference indicating an excursion of the pixel location outside the selected gamut that is referenced from a reference point, and in which the indication is an element on a graph including an angular location reference indicated along a first axis of the graph and a distance reference to the pixel location from the reference point indicated along a second axis of the graph.
2. The display for showing information from a video frame according to claim 1 , in which the reference point is within the selected gamut.
3. The display for showing information from a video frame according to claim 1 , in which the reference point is a white point.
4. The display for showing information from a video frame according to claim 1 , in which the distance reference is a distance from an outside edge of the selected gamut to the pixel location.
5. The display for showing information from a video frame according to claim 4 , in which the distance is a relative distance of the pixel location between an outside edge of the selected gamut and a second reference point.
6. The display for showing information from a video frame according to claim 5 , in which the relative distance is a linear or non-linear representation.
7. The display for showing information from a video frame according to claim 5 , in which the second reference point is an edge of a non-selected gamut.
8. The display for showing information from a video frame according to claim 5 , in which the second reference point is an edge of a chromaticity diagram.
9. The display for showing information from a video frame according to claim 1 , in which the representation is colored to match a color of the pixel color in the video frame that exceeds those colors within the selected gamut.
10. The display for showing information from a video frame according to claim 1 , further comprising a color bar indicating an individual color of the selected gamut for each angular location reference.
11. The display for showing information from a video frame according to claim 1 , further comprising a visual representation of the video frame in which colors of individual pixels outside of the selected color gamut appear as falsely colored pixels.
12. The display for showing information from a video frame according to claim 11 , in which colors of individual pixels within the selected color gamut retain their original color.
13. The display for showing information from a video frame according to claim 1 , in which the graph further comprises:
a color bar extending along the first axis of the graph indicating an individual color of the selected gamut for each angular location reference; and
a bar at the angular location reference for the pixel location, the bar extending along the second axis and indicating excursion of the pixel location outside the selected gamut.
14. A video waveform monitor, comprising:
an input for receiving a video including one or more video frames;
a video processor for analyzing the one or more frames of the video; and
a display for showing information from the one or more video frames relative to a selected gamut including a defined set of colors, the display including an indication of a pixel location for a pixel color in the video frame that exceeds those within the selected gamut, in which the indication of the pixel location includes constructing a line having a rotation angle indicating the pixel color and a location reference indicating an excursion of the pixel location outside the selected gamut that is referenced from a reference point, and in which the indication is an element on a graph including an angular location reference indicated along a first axis of the graph and a distance reference to the pixel location from the reference point indicated along a second axis of the graph.
15. A method of illustrating an amount of gamut excursion of a pixel in a frame of video that has a color that is not within a defined set of colors for a selected gamut, the method comprising:
determining a color of a pixel in the frame;
evaluating whether the color of the pixel is within the defined set of colors for the selected gamut;
generating a location graph; and
adding an indication on the location graph for only those pixels of the frame that have a color that is not within the defined set of colors for the selected gamut, the location graph including a first axis indicating an angular location of the pixel and a second axis indicating an excursion of the pixel outside the selected gamut.
16. The method according to claim 15 , in which the indication on the location graph includes a location reference for each pixel of the frame that has a color that is not within the defined set of colors for the selected gamut.
17. The method according to claim 16 , in which the location reference is an element on the location graph that includes angular location references and distance references from a predefined reference point.
18. The method according to claim 17 , in which the predefined reference point is a color point within the selected gamut.
19. The method according to claim 18 , in which the distance references indicate a scaled distance between an edge of the gamut and a second reference point.
20. The method according to claim 19 , in which the second reference point is an edge of a non-selected gamut.