1. Canon's RAW visible area is slightly larger than in-camera JPEG
2. Jpeg preview, two smaller previews (to show on camera screen), RAW image.
3. unpack() just unpacks opened file to unprocessed bayer data array. Use dcraw_process to convert to RGB (internally) and dcraw_mem_image() to export 3-channel RGB bitmap.
4-5. know nothing about OpenCV, sorry.
1. Canon's RAW visible area is slightly larger than in-camera JPEG
2. Jpeg preview, two smaller previews (to show on camera screen), RAW image.
3. unpack() just unpacks opened file to unprocessed bayer data array. Use dcraw_process to convert to RGB (internally) and dcraw_mem_image() to export 3-channel RGB bitmap.
4-5. know nothing about OpenCV, sorry.