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Date Posted: 18:05:43 10/04/02 Fri
Author: Michel
Subject: Re: Memory problems in envision??? By the way...
In reply to: Dave Bracken 's message, "Re: Memory problems in envision??? By the way..." on 09:54:46 10/03/02 Thu

Hi Dave,

I also worked on a document capture program which was similar. The main bottleneck is the saving of the images. As the tiff file gets bigger, the saving becomes slower and slower. I would not write directly to a tiff file during the scanning. What I used was a the freeware Qdb database components. I don't recall the exact web site, but if you search on www.google.com for "TQdb and Delphi" you should find it. TQdb is very fast to store raw binary data to disk. You need a temporary store that will not compress the file and have minimum index overhead.

The zooming and antialiasing are another factor, but probably not as significant. You could make this an option in the user interface to give the user a choice.

Best regards,


>>I am having a problem with the envision library. I am
>>using a Pegasus ScanXpress ISIS tool to do high speed
>>scanning. I then create a dib graphic and assign it to
>>the envision control. Then i save the image out to a
>>Here is the problem:
>>After about 10 images going through the scanner, the
>>software slows down considerably. If i turn off the
>>anti-aliasing, and also make sure the zoom factor is
>>set to an easily dividable number (such 50%) it seems
>>to work fine. But i really need the ability to scan
>>and display the images at different zoom factors, and
>>really need the anti-aliasing turned on.
>>We are a document imageing company and some of the
>>files we scan can be anywhere from 10 to 500 pages. My
>>software scans each image and puts it in the
>>imagescrollbox, and saves the file out to a
>>single-page tiff.
>>The ScanXpress control has an afterscan event. After
>>each image is pulled in, i have the image put into a
>>Tdibgraphic and assigned to the imagescrollbox. Then i
>>free the Tdibgraphic. Then i immediately save the
>>image out to a Tiff File.
>>In the Before Save event of the imagescrollbox, i set
>>the compression of the ttiffgraphic to tcGroup4.
>>It is as if the imagescrollbox is not freeing up the
>>memory after the savetofile call. Do i need to call
>>some method or something that will free up the memory
>>allocated by the image scrollbox after the save?
>>This does not happen on my p.c. But my p.c. is the
>>development box. It only happens when i put the
>>software on other machines.
>>Please advise what i can do to speed up the software.
>>Thank you,
>Also wanted to let you know that i ran the software
>through MemProof, and memproof says there are no
>memory leaks detected. So i wonder if its maybe due to
>the fact that the office pc's here are just inferior
>in memory and processer speed.
>Thanks again in advance for any light you can shed on
>this subject.
>I am using version 2 beta 1, with Delphi 5 Enterprise,
>on windows 2000 pro.

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