xiQ - Technical Manual Version 1.35
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4.2.
Video Formats
4.2.1.
Full Resolution
By default, each camera outputs a full resolution image based on its sensor specification.
However, on some sensors, the actual output resolution can deviate from the specification if a color mode is used (see.
4.2.2.
ROIs – Region Of Interest
ROI, also called area-of-interest (AOI) or windowing, allows the user to specify a sub-area of the original sensor size for read-out.
Depending on the sensor xiQ cameras support the definition of one single ROI by specifying the size (width and height) as well as
the position (based on upper left corner) of the of the sub-area. Since the utilized CMOS sensors rely on the output of full lines,
only the decrease of lines, i.e. the vertical resolution, results in an increase of frame rate.
Please note
3.5 Model Specific Characteristics
4.2.3.
Downsampling Modes
Downsampling describes the possibility of reducing the image resolution without affecting the sensors physical size, ie. without
cropping the image. This feature is useful when optics are used, that are particularly fitted to a certain sensor size and if it is
necessary to maintain the full image circle on the sensor.
Downsampling can be achieved in two ways: binning and skipping.
4.2.3.1.
Binning
When binning is applied, the image is divided into cluster of k×k pixels, where all pixels in each cluster are interpolated and result
in the value of one output pixel. For example, a 2×2 binning produces 2×2 pixel clusters and results in images with ¼ of the
original resolution.
4.2.3.2.
Skipping
When skipping is chosen, only every n-th pixel is used to create the output image.
For example, with a 2×2 skipping, every odd number line used and every even number line is skipped, every even number pixel
in line is skipped as well, resulting in an image with ¼ of the original resolution. Skipping is a faster binning mode, but also
introduces more aliasing effects.
