The Pixel Addressing feature controls the number of pixels that are read from the ROI.
Pixel Addressing is controlled by two parameters – a Pixel Addressing mode and a value. The mode of Pixel Addressing can be decimation (0), averaging (1), binning (2) or resampling (3). The Pixel Addressing value ranges from 1 to 6. Not all Pixel Addressing values are supported on all cameras.
With a Pixel Addressing value of 1, the Pixel Addressing mode has no effect and all pixels in the ROI will be returned. For Pixel Addressing values greater than 1, the number of pixels will be reduced by the square of the value. A Pixel Addressing value of 2 results in 1/4 of the pixels; a value of 3 results in 1/9 of the pixels; a value of 4 results in 1/16 of the pixels; a value of 6 results in 1/36 of the pixels.
The Pixel Addressing mode determines how the number of pixels is reduced. The decimation mode will skip all the pixels in the block except for the first group of four. At the highest Pixel Addressing value of 6, a 12 x 12 block of pixels is reduced to 2 x 2. At this level of reduction detail in the scene can be lost and color artifacts introduced on a color sensor.
In decimation mode, the Pixel Addressing values produce the following results:
Value of 2: Read out 2 pixels, skip 2 pixels
Value of 3: Read out 2 pixels, skip 4 pixels
Value of 4: Read out 2 pixels, skip 6 pixels
Value of 6: Read out 2 pixels, skip 10 pixels
Pixel Addressing value of 2
Pixel Addressing value of 3
Pixel Addressing value of 4
Pixel Addressing value of 6
For monochrome cameras, examples of the blocks of pixels to be reduced (when using decimation) or summed (when binning) are shown below:
Pixel Addressing Value of 2 x 1
Pixel Addressing Value of 1 x 2
Pixel Addressing Value of 2 x 2
The averaging mode (available on some PL-B cameras) will average pixels at the same location of the 2x2 kernels within the larger block of pixels. On a color camera, the averaged pixels are all the same color, resulting in a 2x2 Bayer pattern kernel. This allows details in the blocks to be detected and reduces the effects of the color artifacts.
The binning mode will sum pixels at the same location of the 2x2 kernels within the larger block of pixels. On a color camera, the binned pixels are all the same color, thus reducing the block to a 2x2 Bayer pattern kernel. Unlike binning with CCD sensors, this summation occurs after the image is digitized, so that no increase in sensitivity will be noticed but a dark image will appear brighter.
The resampling mode is only applicable to some color cameras. This mode uses a different approach involving the conversion of the Bayer pattern in the blocks to RGB pixels. With a Pixel Addressing value of 1, resampling has no effect. With a Pixel Addressing mode of 2 or more, resampling will convert the block of 10-bit pixels to one 30-bit RGB pixel by averaging the red, green and blue channels. The 30-bit RGB value is output from the camera when the video format is set to YUV mode. Resampling will create images with the highest quality and the least artifacts.
Pixel Addressing will reduce the amount of data coming from the camera. However, only the Decimate mode will permit an increase in the frame rate. Averaging, binning and resampling modes will have the same frame rate as if the Pixel Addressing value was 1.
When to Use
Use this feature when:
You want to reduce the amount of data output from the camera while maintaining a large region of interest
For decimation only: you want to increase the frame rate while maintaining a large region of interest
How to Use