GetImageLine

Description

Returns the array of pixel values at the specified horizontal line of the currently acquired frame.


Syntax

[VB]
Value=objActiveGige.GetImageLine( Y )

[C/C++]
HRESULT GetImageLine( short Y, VARIANT* pArray );


Data Types [VB]

Y: Integer
Return value: Variant (SAFEARRAY)


Parameters [C/C++]

Y [in]

The y-coordinate of the line in the image

pArray [out,retval]

Pointer to the SAFEARRAY containing the pixel values in the line

Return Values

S_OK

Success

E_FAIL

Failure.

E_INVALIDARG

Invalid input argument.

Example

This VB example grabs a frame, retrieves the 33th row of pixels and displays the value of 11th pixel in the row.

Dim pix as Long
ActiveGige1.Grab
Line=ActiveGige1.GetImageLine(32)
pix=Line(10)
if pix < 0 then
pix=65535-pix
endif
MsgBox Line(10)

Remarks

The array returned by GetImageLine is a copy of the actual raw of pixels. Modifying elements of the array will not change actual pixel values in the frame buffer. The type of data and dimension of the array returned by GetImageLine depends on the output format of the video as specified in the following table:

Camera Pixel Format	Output Format	Data type	Dimension
Mono8	8-bit monochrome	Byte	0 to SizeX -1
Mono10, Mono12, Mono16	16-bit gray monochrome	Integer (word)	0 to SizeX -1
YUV411, YUV422, YUV444, RGB8, BGR8, Bayer8	24-bit RGB	Byte	0 to SizeX * 3 - 1
RGB10, RGB12, RGB16, BGR10, BGR12, Bayer10, Bayer12, Bayer16	48-bit RGB	Integer (word)	0 to SizeX * 3 - 1

The value of the y coordinate must not exceed the height of the video frame, or the error will occur. For integer (word) type of data you can receive negative numbers if pixel values exceed 32767. In C and C# you can convert signed integers to unsigned ones by using data casting. To get rid of negative values in VB and Delphi, subtract them from 65535 (see example above).

Note that in C/C++ applications it is required to call SafeArrayDestroy() to delete the SAFEARRAY returned by GetImageLine.