WIA with Access VBA slow - ms-access

Question

I have a macro running in MS Access 2013 which was created to scan documents from an HP Scanjet Enterprise Flow 7500 scanner, save the results as a PDF and automatically email the file to someone else in our organization.
The macro itself runs as it should, however compared to the HP software which comes with the scanner, the scanning portion of the macro takes much longer. With the HP software, the time to scan 23 pages was about 30 seconds. With the macro, I had about 3-4 sheets scanned in that time. Please find below the code I'm using to control the scanner. Does anyone see anything that could be improved or changed to increase the speed of execution?
Const WIA_FORMAT_JPEG = "{B96B3CAE-0728-11D3-9D7B-0000F81EF32E}"
Private Sub cmdOK_Click()
Dim intPages As Integer 'number of pages
Dim img As wia.ImageFile
Dim strPath As String
Dim strPathImg As String
Dim strFileJPG As String
Dim txt_id As String
Dim strRPTScan As String
strPath = "H:\Scan\" 'set path to save files
strPathImg = "H:\Scan\Images\"
intPages = 1
On Error GoTo ErrorHandler
'scan
ScanStart:
Dim DialogScan As New wia.CommonDialog
Dim DPI As Integer
Dim PP As Integer
Dim l As Integer
Dim Scanner As wia.Device
Dim intVerticalExtent As Integer
Dim intOneTwoSided As Integer
Set Scanner = DialogScan.ShowSelectDevice(wia.WiaDeviceType.ScannerDeviceType, False, False)
'Set page length
Select Case fraPaperFormat
Case 1
intVerticalExtent = 1650
strRPTScan = "rptScan11"
Case 2
intVerticalExtent = 2100
strRPTScan = "rptScan14"
End Select
'Set single or two-sided scanning
Select Case fraSingleTwoSided
Case 1
intOneTwoSided = 1
Case 2
intOneTwoSided = 5
End Select
'Set scanner properties depending on userform letter format values
With Scanner
.Properties("3088").Value = intOneTwoSided 'determined above
.Items(1).Properties("Horizontal Resolution").Value = 150
.Items(1).Properties("Vertical Resolution").Value = 150
.Items(1).Properties("6149").Value = 0 'x point to start scan
.Items(1).Properties("6150").Value = 0 'y point to start scan
.Items(1).Properties("Horizontal Extent").Value = 1275
.Items(1).Properties("Vertical Extent").Value = intVerticalExtent 'determined above
End With
'Start Scan if err number -2145320957 Scan document finish
Do While Err.Number <> -2145320957 'error number is ADF status don't feed document
On Error GoTo here
Set img = Scanner.Items(1).Transfer(WIA_FORMAT_JPEG)
strFileJPG = strPathImg & CStr(intPages) & ".jpg"
img.SaveFile (strFileJPG) 'save files .jpg in temp folder
DoCmd.SetWarnings False
DoCmd.RunSQL "insert into scantemp (picture) values ('" & strFileJPG & "')" 'insert picture temp to table scan temp
intPages = intPages + 1 'add number pages
here:
Loop
'after finish scan start convert to pdf
Any help would be appreciated.

Answer 1

Obviously, the HP application can do a faster job than any VBA code, as the HP application can probably command the scanner to scan all the pages in the ADF, and you're just doing it one by one. As far as I know, using WIA, you can't work around this.
One way you might be able to optimize your code, is to first scan all the images and add them to a collection, then to save all the files in the collection to temporary files, then add them to the database in a single query, instead of processing each image separately.
A more optimized scanning solution would implement multithreading to scan and process scans simultaneously. VBA has no native implementation of multithreading, but there are a couple of solutions around there on the web, each having their own limitations.