Basler L100k User Manual

Contents

Basler L100k User Manual Manual pdf 43 page image

Operation and FeaturesBASLER L100k Series 3-11DRAFT3.5.1 Balancing the Gain on Odd and Even PixelsAs described on the previous page, gain alignment between the channels is important to maintainuniform output data with minimal gray value differences between odd and even pixels.In some applications, multiple cameras are used, for example, when several line scan camerasare used next to each other to form one large image. Another example is that a camera in anexisting application is replaced. In these cases, it is also necessary to balance the gain betweencameras.To meet the goals of balanced channels and comparable camera output, each Basler camera iscalibrated before it leaves the factory. This calibration procedure has the following effects:• The factory gain settings for the odd and even channels are aligned so that they equallyamplify the signal and a uniform output is achieved on both channels. In addition, they areset to a low gain value to obtain an optimal operating point (low noise, good odd/even chan-nel match)• There are reference gain values which can be used to calculate higher or lower odd andeven gain settings so that the channels remain balanced.• All cameras have default gain settings and reference gain values which match the output of afactory master camera of the same type. This output is referred to as 0 dB. So if a camera’sgain is set to 2 dB, this means 2 dB more than the gain of the master camera.The reference gain values can be used to calculate higher or lower gain settings that will keep theodd and even channels in balance and comparable to other cameras of the same type.If you use the Gain setting in the Camera Configuration Tool Plus (see Section 4.1) to set the gainon your camera, an “auto-balance” feature will automatically use the stored reference values tokeep the channels in balance. If you want to set the camera so that the channels are not balanced,you can use the Gain Balance setting to change the gain on the even pixels only.If you use binary commands (see Section 4.2) to set the gain, you can use the reference valuesto calculate gain settings that will keep the channels in balance. To do this, you must select adesired gain in dB to achieve and then use the reference values along with the formulas shownon pages 3-12 through 3-15 to calculate the required settings for the odd pixel gain and for theeven pixel gain. You can then enter the calculated settings into the camera using the appropriatecommands.3.5.1.1 Refresher on dBA value given in dB is basically a factor. The generalformula to calculate a gain factor in dB is as follows:Or, in other words, an increase by 6 dB corresponds to afactor of 2. A decrease by 6 dB corresponds to a factor of0.5.Gray value [DN]light intensity+ 6 dB- 6 dBx 2x 0.5dB 20 camera outputreference camera output-----------------------------------------------------------------⎝ ⎠⎛ ⎞log×=