Imatest esfrChart. Detected gray patches may not be correct.

Hi, I'm trying to use the esfrChart() function to analyze a set of images. On roughtly 20% of the images, matlab throws the following error:

Detected gray patches may not be correct. Check if image is valid and consider changing detection sensitivity in case no registration points are provided.

The images are extremely similar. This first image works:

This second one throws the error:

I've tried inputting the registration points myself as well as changing the sensitivity, which didn't help. I also tried cropping the images in case the distortion near the edges was affecting things, but cropping didn't change which images work and don't work either.

What is this verification step where this error is thrown and is there a way around it? Is there anything that could be done when taking the images to make them work better?

Answer 1

[Keerthana Chiruvolu]

Hi Sara,

I understand that adjusting the sensitivity, registration points were of no help.

Refer the Tips section in the esfrChart function, to know more about the valid input to the function.

For more information, refer the sample examples for esfrChart, displayChart, displayColorPatch functions.

[Sara nagelberg]

None of this helps; we had a bit of distortion in the image and the error went away for a while once we corrected the distortion. It is reappearing again now, even though there is minimal distortion. Really I just want a way to skip the verification step.