Camera Controls

Main

The Main tab of the camera controls dialog gives the user access to the main camera controls including exposure, region-of-interest, bit-depth, decimation (subsampling) and data rate:

Exposure

Exposure is the primary control and should be set according to the subject image and current lighting. The scale is logarithmic in order to provide the greatest amount of control to the user. You can either use the slider to control the exposure, or you can type the exposure into the text box located to the right of the slider.

Autoexposure

Autoexposure has two modes indicated by the buttons "Manual" and "Automatic". When Manual is selected, pressing the Auto-Expose button cause the camera to optimize its exposure once for the current live view. After this, the camera maintains that resulting exposure level. When Automatic is selected, the camera will operate in continuous autoexposure mode whereby the camera continues to adjust the exposure of the camera to optimize the current live view so long as the camera is imaging in this mode.

Region of Interest Readout (ROI)

Region of Interest Readout is a means of telling the camera to send only a portion of the image data corresponding to a user-defined, rectangular region. To define a region of interest, draw a rectange on the active camera image holding down the left mouse button. The region should be visible as a red-and-white marque. Defining a region of interest and then depressing the "Set ROI" button on the control panel will cause the camera to send only the image data corresponding to the defined region. An ROI is useful for increasing framerates and for reducing the amount of image data that the host computer needs to handle.

Subsampling (Decimation)

The camera is capable of decimation. When the subsampling value is changed to 2x, then the camera only reports every 2nd pixel in both the horizontal and vertical directions resulting in an image that is ¼ of the size of the full image. Subsampling is useful when you want a higher frame rate while maintaining the full field of view (at the cost of lower resolution). A higher framerate can also be achieved by employing a region of interest. Note: With Prosilica's EC-CCD cameras that have binning functionality, the Subsampling feature causes the camera to enter 2x2 binning when 2x is selected.

Limit Frame Rate

The Frame Rate control can be used to regulate the framerate to a fixed rate. The frame rate limit must be set to some value less than the free running rate that would be acheived at the given exposure settings. The free running frame rate will generally increase as the exposure time is decreased. The limit frame rate function can be used to set the framerate to a desired setting regardless of the exposure time (as long as exposure time is not limiting the framerate to an even lower rate).

Bandwidth

The Bandwidth control is used to control how fast the data moves from the camera to the host computer to which it is connected. You may need to regulate the bandwidth if you have multiple cameras connected to a single firewire computer interface. If you have two cameras daisy-chained together, you would need to use a Frame Rate value of 1/2 so that each camera takes 1/2 of the bandwidth of the firewire bus. If you had four cameras, then you would use a Frame Rate value of 1/4, etc.

Color Balance

The color balance tab on the control dialog gives access to color balance controls for color cameras. This tab does not appear when controlling a monochrome camera.

Automatic White Balance

To white balance the camera, place a white object in the field of view that completely fills the image. Then click the "Automatic White Balance" button on the "Color Balance" control tab. The camera will automatically white balance. These white balance settings will remain until the camera is powered down. Note, if a white object cannot fill the whole field of view, you may also select a Region of Interest (ROI on Main tab) that shows a white object. The color balance may then be executed on the ROI instead of the whole image. The camera can then be switch back to the desired field of view and the camera will maintain the color balance. If you wish the camera to maintain the color balance settings even after power has been disconnected, you can save the camera settings using the Configuration Memory settings descibed below.

Red / Blue slide bars

The camera white balance can also be manually adjusted using the "Red" and "Blue" slder bars.

ADC

The ADC tab on the control dialog gives the user access to internal camera controls that govern how the analog "real-world" image is converted to digital data before being sent to the host computer. These slider controls are main image quality controls and should be used in conjunction with the live histogram to acheive the best image results.

Exposure

As above, exposure is the primary control and should be set according to the subject image and current lighting. This control also appears on the "Main" tab, but is repeated here for convenience. You can either use the slider to control the exposure, or you can type the exposure into the text box located to the right of the slider.

Gain

Generally speaking, the Gain control should be left at "0" since the camera is calibrated at the factory to give the most intuitive response at zero gain. As the gain is increased, the camera appears more sensitive. Remember that as the gain is increased, it magnifies not only the image signal but also magnifies any noise that may be in the image. It is generally better to add more illumination to the scene than to increase the gain.

Offset

When the Offset is set to "Calibrated" then the camera chooses a factory calibrated offset which is correct when gain is set to "0". If the Gain is not set to zero, then Offset should be set to "Manual Control" and adjusted using the slider bar. The adjustment should be made while viewing the live histogram to maximize image quality.

Gamma

The Gamma checkbox should be left unchecked. Gamma is a concept familiar to film photographers as a means of boosting the brightness of the grey pixels while maintaining the value of the darkest and brightest pixels. It is a non-linear function and is useful for creating a more visually pleasing image. However, since it is applied to the data after imaging, it does not improve the analytical quality of the data.

External Trigger

In most machine vision applications external events control when the camera should acquire an image. Prosilica cameras have a complete and versatile set of external trigger controls. These controls tell the camera how to configure the physical inputs and outputs of its various trigger lines. By default, the camera starts up in self-trigger, or free-running, mode whereby the camera takes images as fast as it can without reference to external events. When the trigger is activated then the camera will only acquire images when it receives signal on a external trigger input. This control feature also determines what type of signals are sent to the trigger outputs as well.

Trigger Mode

The Trigger input can be configured as "Off", "Edge", or "Integrate". When set to "Off" the camera runs in continuous mode as fast as it can. When set to "Edge" the camera will respond by grabbing an image when the trigger input signal becomes active. When set to "Integrate", the camera will capture an image and will expose it for as long as the trigger input is active (analogous to the "bulb" function on a film camera).

Polarity

The trigger inputs can be configured as "active-high" or "active low". When active-high, the trigger will capture an image when the signal on the trigger input moves from low to high (TTL levels). When active-low, the camera will capture an image when the external signal changes from high to low.

Sync-Out

The Sync control determines the behavior of the trigger output signals. The trigger outputs can be configured as "Trigger-in", "Exposing" and "Trigger-ready". The "Trigger-in" setting means that the Trigg-out port of the camera will mimic whatever appears on the Trigg-in line. This can be useful for triggering multiple cameras by daisy-chaining the triggers. It can also be used to trigger other devices such as flash lamps. The "Exposing" setting sets the Trigg-out port to report a high signal so long as the camera is exposing an image. This can be useful for controlling lighting or for feedback to factory controls. The "Trigger-ready" setting means that the Trigg output signal will go high as soon as the camera is ready to be triggered again.

Trigger Delay

Trigger delay controls the time between the signal change on the external trigger input and the start of image capture. In many cases it is necessary to adjust the delay to properly sequence and external event and the capture of an image.

EDR - Extended Dynamic Range

Prosilica cameras include a sensor function called Extended Dynamic Range (EDR) that is usefull in certain difficult lighting situations. EDR reduces the camera response to very bright parts of the subject image while maintaining full exposure for those parts of the subject that are not so bright. In situations where there may be saturation from glare or bright reflections, EDR can be applied effectively.

EDR is also called "Multislope Integration". It is fairly difficult to set up properly, but it can make a big difference in certain situations.

Note: The EC750 camera has only limited EDR capability at this time. Contact Prosilica for details.

Memory - Non-volatile Configuration Memory

Newer models of Prosilica cameras have a non-volatile configuration memory that can be used to set up the camera prior to use. This can be especially useful when the camera is being used with software that does not provide full camera controls. In such a case the camera can be set up with the correct exposure, color balance, and trigger settings independently of third party software. When the camera is subsequently powered up, it will load the "Current Configuration"

Modify Configuration Memory

In order to use this function, first configure the camera settings to achieve the designed result. Then chose a 'configuration' by choosing a configuration ID number beside "Save as configuration". The camera can hold several different configurations. Clicking "Save" will save the camera configuration under the ID selected. Clicking "Erase All" will reset the camera to the factory settings.

Current Configuration

After saving a configuration under the "Modify Configuration Memory", you can choose which configuration the camera will load when powered up. Selecting a configuration ID beside "Load configuration from non-volative memory" will determine which configuration is loaded.