Sometimes less means more – Subsampling, binning, or scaler
To reduce the image resolution and still having the same field of view, you have different ways depending on the sensor model: subsampling, binning, or scaler. But how do they differ?
Subsampling skips multiple sensor pixels when reading out the image data. This reduces the amount of data to be transferred and enables higher camera frame rates. The captured image has a lower resolution but still the same field of view compared to the full-resolution image.
Monochrome sensors and some colour sensors ignore the Bayer pattern and the colour information gets lost (mono subsampling).
Subsampling can also be done in the pixel preprocessing on the camera. This process reduces the data volume per image, but does not increase the frame rate.
- If the pixel values are added, the image brightness increases.
- If the pixel values are averaged, the image noise is reduced.
Most monochrome sensors and some colour sensors combine neighboring Bayer pattern pixels; in this case, the colour information gets lost (mono binning).
With the scaler, the image resolution can be reduced in adjustable factors. Thus, the data volume can be reduced. The captured image has a lower resolution but still the same field of view compared to the full-resolution image. Unlike subsampling or binning, the image is reduced almost continuously and the image brightness will not change.
Setting the image resolution in uEye Cockpit
Open the camera properties in uEye Cockpit via “uEye > Properties”. Depending on the opened camera model, you can configure subsampling, binning, or scaler in the “Size” tab.
Tip: Image profiles
In the “Size” tab, you can set a predefined resolution via a profile. Depending on the profile and sensor model, the camera driver sets automatically the requested size via AOI, binning, subsampling, or scaler to receive the best image quality.
The advantage of subsampling is that the frame rate can be increased without changes in image brightness or contrast. The scaler allows the same as subsampling but with finer intermediate steps. However, the scaler is only supported by certain sensors.
The advantage of binning is that image brightness can be increased. This advantageous in applications in which a flash cannot be used for example for light-sensitive samples or reflective surfaces. Also you can use a shorter exposure time which is important for moving objects.
|Field of view||unchanged||unchanged||unchanged|
|Frame rate||may increase||may increase||may increase|
|Image contrast||unchanged||may increase||unchanged|
|Image brightness||unchanged||may be brighter||unchanged|
|Image noise||unchanged||may be better||unchanged|
For more information on the settings, refer to the uEye manual at http://en.ids-imaging.com/manuals-ueye.html.