Sheet Validity
All images in an input file may not be score images: we can find illustration pages, blank pages, etc. Generally, the SCALE step is smart enough to detect that there is not enough “staff material” in a sheet and thus detect an invalid sheet from the OMR point of view.
When running in batch, the engine sets the invalid flag for the sheet. When in interactive mode, we are prompted to confirm whether the sheet is really invalid.
How to know if a given sheet has been set to valid or invalid?
In the Sheet pull-down menu, we can look at the Current status item:
- It indicates the sheet current validity status
- By pressing on the menu item, we toggle the sheet validity status.
| Valid sheet | Invalid sheet |
|---|---|
 |  |
Also, the text on the sheet tab turns red for an invalid sheet.
We can decide to display or not the tabs for invalid sheets, via the menu item View | Display invalid sheets.
A sheet declared as invalid is no longer processed: no transcription, no export, no printing, nothing! Unless of course if we realize we’ve made a mistake and decide to set it back to valid after all!
But validity is supposed to represent the real status of the sheet from the OMR perspective; we should not use it to include or exclude this sheet for some processing. A side effect of modifying the validity status of a sheet is to nullify all its OMR data!
Instead, we should use the sheet selection mechanism or the even more powerful Split and Merge tool.