ISOCAM Interactive Analysis User's Manual Version 5.0 - ISO - ESA

166 CHAPTER 15. CIA DATA STRUCTURE HIGH-LEVEL ARCHITECTURE
11. SIZE: Number of IMAGEs in the SPD SCD, and the number of FRAMEs in the ERD
SCD. Type: integer.
12. DATA: Cube containing IMAGEs in the SPD SCD. Does not exist for ERD SCD 5 . Type:
integer IDL cube. Unit: ADU.
13. EOI: Cube containing EOI FRAMEs. Only exists for ERD SCD 5 . Type: integer IDL
cube. Unit: ADU.
14. RESET: Cube containing RESET FRAMEs – present in both ERD SCD and SPD SCD 5 .
Type: integer IDL cube. Unit: ADU.
15. MODEL: Cube available for holding processed images. MODEL has the same dimensions
as DATA or RESET and is only present in an SPD SCD. Type: float IDL cube.
16. EOI MODEL: Similar to MODEL, though used for processed EOI frames. EOI MODEL
is only present in ERD SCD. Type: float IDL cube.
17. RESET MODEL: Similar to MODEL, though used for processed RESET frames. RE-
SET MODEL is only present in ERD SCD. Type: float IDL cube.
18. MASK: A cube of the same dimensions as DATA, EOI or RESET. Each pixel in the
MASK corresponds to a pixel in DATA (SPD SCD), or to a pair of pixels in EOI/RESET
(ERD SCD), and records the status of that pixel. Masked pixels have one of two possible
byte representations in the MASK. This is determined by the value of the system variable
!MASK. Setting !MASK to 0 selects the simple MASK and 1 selects the complex MASK
(for configuring !MASK see Section 2.3.4). In both cases the first bit of the MASK value
determines if a pixel is good or bad: 0 is good and 1 is bad. The simple representation
only uses this first bit so the MASK will be filled with ones or zeros. The complex
representation uses the remaining 7 bits to record more information about the masked
pixel. For example, if MASK[16,16,0] = 2, then pixel [16, 16] is dead in the first IMAGE
of DATA. If MASK[16,16,0] = 4 then the same pixel has been deglitched. In the complex
representation a pixel is still only considered to be bad if the first bit of the corresponding
MASK pixel is 1, so this means odd MASK values are bad and even are good regardless of
what other status the pixel may have. A list of possible types or keywords of flagged pixels
is given in the table below. Section 16.4 describes how the MASK may be manipulated.
Type: integer IDL cube.
type / keyword rank description
bad 1 bad pixel
dead 2 dead pixel
glitch 4 deglitched pixels
memory 8 pixel affected memory effects/transients
blind 16 blind pixel (i.e. not illuminated)
qla 32 pixels flagged as bad by qla or csh
spare 64 spare
ext source 128 extended source
5 Do not modify this field directly. It contains a reference copy of your CAM image data.