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Exact same code producing different color scheme MATLAB plot

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Palash Agrawal
Palash Agrawal on 25 Jun 2019
Commented: Image Analyst on 26 Jun 2019
Hello
When a colleague below runs the code attached, they claim to get a figure 4 with a color scheme that look likes attached image 1. When I run the exact same conde on MATLAB online, I get firgure 4 that looks like attached image 2. I cannot figure why this is and need my code's figure 4 output too look like that in image 1.

  2 Comments

Geoff Hayes
Geoff Hayes on 26 Jun 2019
Palash - which version of MATLAB is your colleague using? What is the version of MATLAB online?
Palash Agrawal
Palash Agrawal on 26 Jun 2019
Geoff I am using Matlab 2018b and he is using Matlab 2016 I believe.

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Answers (1)

Image Analyst
Image Analyst on 26 Jun 2019
You're using imagesc(), which I hate and never use because it applies default colormaps that you never asked for. The one image you had uses the "jet" colormap, which was the default before release 2014b, and the other image uses parula which is the current default colormap. I suggest you use imshow() and/or colormap() and apply whatever colormap YOU want instead of using the default.
See Steve's blog for the reasoning behind the change: Steve on Image Processing

  3 Comments

Palash Agrawal
Palash Agrawal on 26 Jun 2019
Hi
I changed the colormap to jet in MatLab using the colormap and got the exact same image. Is there any chance that the jet color map also changed after the 2014 release? Thanks
Walter Roberson
Walter Roberson on 26 Jun 2019
imagesc() and image() both apply the current or default colormap, and it is imshow() that imposes colormaps that you never asked for (such as imposing grayscale in some situations.)
Image Analyst
Image Analyst on 26 Jun 2019
I don't think it changed, but you can print it out and check it
jet(256) % No semicolon so it will print to command window.
or however many colors you think there are.

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