IBM CF Series manual G Gain Memory, NG Normalize Gain

5.1.14.3 G : Gain Memory

Gain control allows light response equalization for each CCD photosite in the scanner. This is required because the amount of light transmitted through the lens is greatest in the center and tapers off towards the edges. Also, the response of individual photosites varies somewhat due to limitations in the manufacturing process. Each byte in the Gain Memory holds a corrective value for a corresponding photosite.

If you enter <D> and a <CR> for “Display”, the contents of the Gain Memory will displayed starting from address 0000. This memory contains 64K 8-bit words. They are displayed 320 at a time. To view the next 320, press <D> and <CR> again. To view the memory starting at an address other than 0000, enter D command followed immediately by the address. You do not need a <CR>, for example, “D2000”.

If you choose <F> for “Fill”, enter, separated by commas, the starting and ending memory locations, and the two-bit hexadecimal value you want to fill the memory. It will write over any values that are already there. You do not need to enter a <CR>. For example,“1000,2000,03”

Choice <M> runs a memory test. If no errors are found , the test indicates “OK”.Otherwise the test indicates “ERROR” and displays the addresses of the bad memory locations.

If you press <Z> to “Clear the Whole Memory”, the entire memory will be filled with zeroes.

If you enter <CTRL+E> the flash memory containing the gain values is erased. All memory locations are set to FF .

5.1.14.4NG : Normalize Gain

If you enter “NG” for “Normalize Gain”, the prompt “Target Pixel Value [E0]:” will appear. Enter “E0”and press <CR> or just press <CR>.

Next , the prompt “Clear Gain Memory [Y]” will appear. If you do not clear the memory, it will use whatever is there for the basis of the new normalization. Scangraphics recommends that you clear the memory before normalization.

The scanner then does a normalization pixel-by-pixel, calculating the gain values required to bring each pixel to the target.Upon completion, it beeps three times, and returns to Camera System Diagnostics Menu.