Sigma LBA-300, LBA-710, LBA-714PC, LBA-712, LBA-708, LBA-500PC Digital Camera and Ultracal Operation

Adjust the Vertical Start value according to the following rules. (Remember you must input even values.) To move the image DOWN, decrease the Vertical Start value. To move the image UP, increase the Vertical Start value.

Adjust the Horizontal Start value according to the following rules. (Remember you must input even values.) To move the image LEFT, decrease the Horizontal Start value. To move the image RIGHT, increase the Horizontal Start value.

When the image is centered be sure to save a <camera>.cam and a <config>.cfg configuration so that you can restore these setup conditions.

7.4 Digital Camera and Ultracal Operation

The Ultracal! operation can be adversely affected by how your digital camera is adjusted. Some digital cameras will have their A to D converter black levels set such that some or all of the negative pixel energy is clipped at Zero. Some may even clip a portion of the positive signal region. From the LBA-PC’s point of view, a properly adjusted camera will never generate a Zero pixel value, thus preserving all of the black baseline negative temporal noise. If your camera has a straight binary output then the Ultracal! operation will yield one of the following three results:

1.If your output image data contains zero pixel values, you will get a warning message that the calibration will not be as accurate as normal. The Ultracal enunciator will turn GREEN to indicate that the obtained calibration results are being used as best as possible

2.If your output image does not contain zero pixel values and the signal is fairly low in magnitude, then the calibration will proceed normally and the results will be good. The Ultracal enunciator will turn GREEN.

3.If your output image does not contain zero pixels, but the image is bright due to a high offset, then a warning message will appear that will ask you to block your beam from the camera. Click OK to accept these conditions. The Ultracal enunciator will turn GREEN.

If the first or third result occurs you may be able to correct this condition by adjusting the black threshold of your camera’s A to D converter. Here is how to proceed. With the LBA uncalibrated and your laser energy blocked from reaching the camera detector, observe the “Min” and “Max” energy values. If Zero’s appear, your camera is set to clip some or all of the negative baseline noise. If these values are running too high the LBA will think you have laser energy hitting the imager. Check your camera operator’s manual to see if a black level adjustment is provided. If you can adjust the black level, do so until the Min. energy value never indicates Zero and the Max. energy value is as low as possible. Now try to run an Ultracal! and see if the results are as in 2 above.

Note: Almost all cameras will exhibit baseline drift. When making adjustments to your camera always allow the camera to come to thermal equilibrium and allow a little headroom on the adjustments to accommodate additional drift over time and temperature variations

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If your camera does not have a black level adjustment, and gives on of the above warnings then you must either accept the reduced accuracy or have your camera manufacturer modify the camera for you.

Operator’s Manual 154 LBA-PC