Image Acquisitionand Proces

12 Image Acquisition Processing with LabVIEW
1.3.2 CUSTOM AND OTHER IMAGE FORMATS
Working with images Þles that are not included in the Þve standard types supported
by IMAQ ReadFile can be achieved either by using a third-party toolkit, or decoding
the Þle using IMAQ ReadFile’s advanced features. Consider the example in Figure
1.9, which shows an image being saved in a custom Þle format. The size of the
image (x,y) is Þrst determined and saved as a Þle header, and then the image data
is converted to an unsigned 8-bit array and saved as well. Opening the resulting Þle
in an ASCII text editor shows the nature of the data (Figure 1.10)
FIGURE 1.9 Save an image in a custom format — wiring diagram.
FIGURE 1.10 A custom Þle format image.
The Þrst four characters in the Þle specify the x size of the image, followed by
a delimiting space (this is not required, but has been included to demonstrate the
technique), then the four characters that represent the y size of the image. When
reading this custom Þle format, the header is Þrst read and decoded, and then the
remaining Þle data is read using IMAQ ReadFile (Figure 1.11).