Hello everybody,
I apologize if this has been answered previously.
I am converting a RGB image to 8 bit image. I assume that the resultant intensity values should be integers between 0 and 255. However I get numbers with decimal values, like. Min 54.752 Max 241.427
In Image Info it says:
Bits per pixel: 8 (grayscale LUT)
Display range: 0-255
Does anybody understand why I get decimal values?
Thanks in anticipation for any help
Hi
@Axonopsis_1
You will find some answers here:
With RGB images, results are calculated using brightness values. RGB pixels are converted to brightness values using the formula value = (red + green + blue) ⁄ 3 or value = 0.299 × red + 0.587 × green + 0.114 × blue if Weighted RGB Conversions is checked in Edit▷Options▷Conversions…↑.
Hope this helps
Thank you
Does the image have a calibration function? It would help if could save the image in TIFF format and post it.
I just discovered that this happens (the decimal gray value) if I define an area within the image with the segmented line tool, that, by the way, I am not able to close. If I define rectangle or oval tools (that are closed by definition),then the gray values are integer within 0 and 255
Hi Mathew and Wayne,
I think that the problem is with open segmented areas, as I said before, not with the conversion from RGB to GRAY.
I am including a RGB tiff image whose closed outer square has Min 133 Max 249. The inner open square has Min 161.642 Max 247.920. I still don`t understand where those decimal numbers come from.
Thanks in advance for the help
A.
Hi, again.
I solved the problem using the polygon selection tool.
However, I still don’t understand where decimal gray values come in the segmented line tool.
Thank you very much!!
A.
ImageJ uses interpolation to measure pixel values along line selections.
Understood!
Thank you very much!
A.
