Just did some digging into the JPEGs from this camera, using a hex editor, and Gimp (using its raw image loader feature, which lets you specify offset, width, height, and raw pixel format), and have figured out a way to get to the raw data in the DT-9885 thermal imager.
Scan the file for the unicode string FPZdnx (yes, it is case sensitive). Because it is unicode, it's 2 bytes per letter. So this is a 12 byte string you are looking for, with the following hexidecimal values:
46 00 50 00 5A 00 64 00 6E 00 78 00
After finding this byte string, the raw 16-bits-per-pixel image data starts exactly 96 bytes past the last byte of that string. So after your byte string scan finds this byte string, jump to the end of the byte string (12 byte jump), and then skip 96 bytes (the raw image header is 96 bytes long) to get to the start of the actual raw image pixel data. Alternatively do a 108 byte jump from the start of the 12 byte string (this will eliminate one step in writing a program that is designed to load the raw data). Unlike FLIR's FFF format, which (when embedded in a JPEG) is split up into JPEG sized chunks (each with a header that states the size of that chunk), the format used by the CEM DT-9885 doesn't use JPEG format in any way for the raw data. It's simply appended to the JPEG section of the image file. To find where it starts, use the technique I mentioned above. Not sure where the width and height are stored though, as I've not reverse engineered the header yet. I will be sure to provide more info as I dig deeper into the header of the raw data section. I assume the same basic format is used for other thermal imagers made by CEM (including their 160x120, and 640x480 thermal imagers). The DT-9885 is a 384x288 thermal imager. The JPEGs it saves have 640x480 for the JPEG compressed image, because they use upscaling, but the raw image stored at the end of the JPEG file is not upscaled at all (unlike the cropped then upscaled raw thermal image saved by the FLIR One).
It was great that you attached pics from your DT-9885 in your posts here. If you, or anybody else here has any other CEM thermal imagers in various resolutions, please post pics from them here too. It would help me to reverse engineer their format.