Split and crop jpg using black background

[onidarbe]

I'm looking for a way to split and crop scanned images to smaller jpg's using a black background. This way I'd like to devide several shop-tickets scanned together as one jpg, into seperate jpg-files.

I hoped to do this in Excel-VBA, but I can't seem to find out how. Now maybe I can do this with writing some *.vbs using the build-in Windows API, can I?

Thanks

[LaVolpe]

Splitting an image into smaller images is easy in theory. Determining where to split can be exremely difficult depending on the requirement. If only splitting say "in half" or "in quarters" then that is easy enough. Howver, VB does not support saving to JPG format. So you'd be able to read a JPG file, but not save in JPG format without help. There is a JPG DLL floating about, though I have never used it. Using GDI+ can save in JPG format. If JPG format is not a concern, VB can save in bitmap format without any problems.

Bottom line, can you be much more specific and descriptive with what you are trying to do, maybe even provide a sample of these shop tickets?

P.S. I think I can visualize what you are attempting. I think this has potential to be a major undertaking. Hopefully the background the tickets are layed over, compared to the foreground of the actual tickets, is sharply contrasted.

[onidarbe]

My project:
I'm trying to automate Excel, putting all my bills, payments, invoices and shop-tickets into one sheet. When I click a line in the sheet the scanned jpg-image pops open.
I've found a way in Excel-VBA to change jpg's into a readable pdf's using a OCR-shell. Then the pdf's are written with regular expressions using data in a second sheet to create a line for each existing pdf, with company/shop-name, date and total price, .... Atferwards it renames these pdf-files with these found keywords.
So I get a file like "20090828 Supermarket food 45.12.pdf" linked to a line in the excel-sheet to be calculated with all the other bills and bank-transfers...

Problem:
Now I'm trying to also scan many small sales-tickets together with a black background, saving time. Automaticly devide them into smaller jpg's on the darker background found within every jpg scanned. Using my Excel-VBA code with help of the SHELL-commands to standard Windows API's or installed programs and *.vbs-scripts.

So what shell-instruction or *.vbs can I write to test split, crop and read the color of pixels from a jpg-file. If I know how to read the color of a jpg and know how to crop and save it, then I can try to write some code to find where to crop the image....

Maybe there is already some code that does this or a small program. But so far I only found Photoshop-Elements which it expensive and not a standard program in Windows.

Can't I use Paint or some DLL in XP?

Thanks.

[LaVolpe]

Can't I use Paint

If this doesn't need to be automated. Paint is ideal
1. Open the JPG in Paint
2. Use the rectangular selection tool
3. Drag/crop the smaller image with the tool
4. Use menu: Edit | Copy To
5. Save the selection to a new jpg file
6. Repeat for the other images

Image processing via code is no small task.

[onidarbe]

Well, it has to be automated

So how can I:
1) Read a color of a specific pixel
2) crop a image
3) save it as a jpg

[LaVolpe]

1. Extract the pixels to an array and process the array. Each pixel is a RGB value expressed in either 3 or 4 bytes depending on how you extract those pixels.
This site is where I began learning about image storage and manipulation. Jump to the lower half of the screen for topics related to bitmaps. JPGs when read by VB are converted to bitmaps internally.

2. You will need to process the pixels to determine that. You probably want to look for lighter pixels to help distiguish the ticket from the background. You might want to google for Magic Wand to see if you can find any VB examples. Most graphics programs use magic wands for crop selection.

3. Use GDI+ or locate any 3rd party DLLs to save as JPG. As I already mentioned, VB cannot save images to JPG format.