Home/ Questions/Q 8773639
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-06-13T18:21:03+00:00

I am using Logitech pro9000 HD webcam. Which have 2 mp zeiss lence and

  • 0

I am using Logitech pro9000 HD webcam. Which have 2 mp zeiss lence and can capture HD video etc. blaa blaa
My code [not exactly the same but integrated in single function.

Now the problem if I use resolution up to 1600 x 1200 everything works fine. And received byte size as follows 

for 640 x 480 VideoHeader.dwBytesUsed are 921600
for 1600 x 1200 VideoHeader.dwBytesUsed are 5760000
from 1600 x 1200 to 3264 x 2448 VideoHeader.dwBytesUsed are 5760000

But for higher resolution from 1600 x 1200 the byte size is same as 1600 x 1200 but my program can’t covert that data to bitmap I event try to set size of bitmap to 1600 x 1200 but nothing works I get only fuzzy at bottom or stretched multiple images at bottom of preview bitmap.
I know this is called interpolation
My question is where the interpolations is implemented actually in driver which I am accessing or the camera application given by company
Means do I am getting the interpolated data or I have to implement the algorithm in my program.
What confused me is if driver is still returning 1600 x 1200 images and software from Logitech is interpolating image to 3264 x 2448 size if this is a case then why I am not getting the 1600 x 1200 image from device event I set video format at init code to 3264 x 2448
[I have set bit to 24 and camera is using Format24bppRgb Pixel Format]
can anyone help me !….

my code is 

Private Sub FrameCallBack(ByVal lwnd As IntPtr, ByVal lpVHdr As IntPtr)
    Dim _SnapSize As Size = New Size(640, 480)
    'Dim _SnapSize As Size = New Size(1600, 1200)
    Dim _SnapSize As Size = New Size(3264, 2448)
    Dim VideoHeader As New Avicap.VIDEOHDR
    Dim VideoData(-1) As Byte
    VideoHeader = CType(Avicap.GetStructure(lpVHdr, VideoHeader), Avicap.VIDEOHDR)
    VideoData = New Byte(VideoHeader.dwBytesUsed - 1) {}
    Marshal.Copy(VideoHeader.lpData, VideoData, 0, VideoData.Length)
    Dim _SnapFormat As System.Drawing.Imaging.PixelFormat = PixelFormat.Format24bppRgb
    Dim outBit As Bitmap
    If Me.IsValidData Then
        outBit = New Bitmap(_SnapSize.Width, _SnapSize.Height, _SnapFormat)
        Dim bitData As BitmapData
        bitData = outBit.LockBits(New Rectangle(Point.Empty, _SnapSize), ImageLockMode.WriteOnly, _SnapFormat)
        outBit.UnlockBits(bitData)
        GC.Collect()
        GC.WaitForPendingFinalizers()
    End If
End Sub
Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    First really sorry that I completely forgot about this question

    The answer is – these structures are for native APIs.

    My camera was 2 mega pixel lens and I was getting proper image at resolution of 1600 x 1200
    The math is simple

    1600 x 1200 = 1920000 Total Pixels

    Pixel format is 24 bpp means 3 bytes for each pixel total size of image is 5760000

    This lens can no longer produce data more than 2 mb that’s why 1600×1200 is the hardware resolution limit for this camera and hardware is not responsible for interpolation for higher resolution image that’s why I have to do it manually after getting original image from camera.

    This is what exactly I did; I capture image of 1600×1200 and write image processing algos to create interpolation and improving quality of that image.
    Project was creating a cheap book scanning device for document scanning. Was done successfully and in use by our clients.

    • 0