Considerations When Using Binning - Basler GIGE VISION ace acA640-100gm/gc Manual

Area scan cameras

Table of Contents

10.6.1

Increased Response to Light

Using binning can greatly increase the camera's response to light. When binning is enabled, ac-

quired images may look overexposed. If this is the case, you can reduce the lens aperture, reduce

the intensity of your illumination, reduce the camera's exposure time setting, or reduce the camera's

gain setting.

When using vertical binning, the limits for the minimum gain settings are automatically lowered. This

allows you to use lower gain settings than would otherwise be available.

For the lowered limits for the minimum gain settings, see Section 10.1 on

Reduced Resolution

Using binning effectively reduces the resolution of the camera's imaging sensor. For example, the

sensor in the acA640-100gm camera normally has a resolution of 659 (H) x 494 (V). If you set this

camera to use horizontal binning by 3 and vertical binning by 3, the effective resolution of the sensor

is reduced to 219 (H) by 164 (V). (Note that neither dimension of the sensor was evenly divisible by

3, so we rounded down to the nearest whole number.)

Possible Image Distortion

Objects will only appear undistorted in the image if the numbers of binned lines and columns are

equal. With all other combinations, the imaged objects will appear distorted. If, for example, vertical

binning by 2 is combined with horizontal binning by 4 the widths of the imaged objects will appear

shrunk by a factor of 2 compared to the heights.

If you want to preserve the aspect ratios of imaged objects when using binning you must use vertical

and horizontal binning where equal numbers of lines and columns are binned, e.g. vertical binning

by 3 combined with horizontal binning by 3.

Binning's Effect on AOI Settings

When you have the camera set to use binning, keep in mind that the settings for your area of interest

(AOI) will refer to the binned lines and columns in the sensor and not to the physical lines in the

sensor as they normally would. Another way to think of this is by using the concept of a "virtual sen-

sor." For example, assume that you are using an acA640-100gm camera set for 3 by 3 binning as

described above. In this case, you would act as if you were actually working with a 219 column by

164 line sensor when setting your AOI parameters. The maximum AOI width would be 219 and the

maximum AOI height would be 164. When you set the X Offset and the Width for the AOI, you will

be setting these values in terms of virtual sensor columns. And when you set the Y Offset and the

Height for the AOI, you will be setting these values in terms of virtual sensor lines.

For more information about the area of interest (AOI) feature, see Section 10.5 on

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