Assistance needed converting raw images with DCRaw

[javalor]

Hi,
I am just started using DCRaw to convert images taken with a Canon
Powershot D20 and CHDK to get pictures into a raw format. I took pictures
of a spherical light integrating sphere, and am having some difficulties
with importing the photos. I use DCRaw to open the photos with settings:
use directory for processing {checked}, white balance {checked}, do not
automatically brighten the image {checked}, output colorspace {raw},
document mode (no color, no interpolation) {unchecked}, document mode
without scaling (totally raw) {unchecked}. interpolation quality
{high-speed, low-quality bi-linear}, half size {unchecked}, do not rotate
or scale pixels (preserve orientation and aspect ratio) {checked), show
metadata in result window {checked}. The problem that I am having is that
not all of the pixels are the same, or generally the same, as there are
some pixels with 0 values and max values; I would expect all of the pixels
to be fairly uniform as it is a picture of a light integrating sphere, or
environment of equal light distribution. Are there any settings I am
missing, or is there another problem I am not considering?
I have attached a sample photo for reference.
Thanks!

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