Radiomics for entire image- not only on segmentation

Operating system:Windows 10
Slicer version:4.10.2
Expected behavior: Features extracted from whole image
Actual behavior: Need segmentation

I am using radiomics to analyze grayscale confocal microscopy images and I do not want to use a segmentation. I would like to analyze the whole image so that i can compare different histogram processes to one another (HE, CLAHE, WL). I want to show quantitatively that structures present in original image are best preserved/enhanced using CLAHE and when other methods are used, structures in the image are lost.
When I segment the images- for example using a threshold, then the darkest regions of the image not captured by the threshold are not being analyzed? I want to compare the entire grayscale images to one another- not just a thresholded region of the images. Is it possible to extract the radiomic features from the whole image without using a segmentation or binary label?