Kiralux™ Polarization Camera with 5.0 MP Monochrome CMOS Sensor

Features

• Monochrome 5.0 MP CMOS Sensor with Integrated 4-Directional Wire Grid Polarizer Array
• High Quantum Efficiency: 72% from 525 to 580 nm (Typical)
• 3.45 µm x 3.45 µm Pixel Size
• Fan-Free, Passive Thermal Management Reduces Dark Current Without Vibration and Image Blur
• <2.5 e^- RMS Read Noise (Unprocessed Images)
• Triggered and Bulb Exposure Modes
• Global Shutter
• USB 3.0 Interface
• ThorCam™ Software for Windows^® 7 and 10 Operating Systems
• Available Polarization Imaging Modes:
  • Intensity (Optical Power) / Stokes Vector S0
  • Degree of Linear Polarization (DoLP; Shown in the Video Below)
  • Azimuth / Angle of Linear Polarization (AoLP; Shown in the Screenshot Above)
  • Unprocessed (Raw)
  • QuadView (Unprocessed, Separated by Polarization)
• SDK and Programming Interfaces Provide Support for:
  
  • C, C++, C#, Python, and Visual Basic .NET APIs
  • LabVIEW, MATLAB, and µManager Third-Party Software
• Azimuth Orientation Engraved on Housing
• SM1-Threaded (1.035"-40) Aperture with Adapter for Standard C-Mount (1.000"-32)
• Compatible with 30 mm Cage System

Jason Mills
General Manager,
Thorlabs Scientific Imaging

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Thorlabs' polarization-sensitive CS505MUP Kiralux™ Camera features a 5.0 MP monochrome CMOS sensor with a polarizer array between the on-chip microlenses and the photodiodes. The wire grid polarizer array is comprised of a repeating pattern of polarizers (0°, 45°, -45°, and 90° transmission axes) and is present on the sensor chip between the microlens array and the photodiodes. The integrated polarizer array and software image processing enable the creation of images that express degree of linear polarization (DoLP), azimuth, and intensity at the pixel level. These features enable many advanced techniques using polarization, for example: stress-induced birefringence detection, surface reflection reduction, materials inspection. The housing features engraved references for the polarization azimuth for ease of alignment.

The camera also offers extremely low read noise and high sensitivity for demanding imaging applications. The global shutter scans the entire field of view simultaneously, allowing for imaging of fast moving objects. The compact housing has been engineered to provide passive thermal management for the sensor, reducing dark current without the need for a cooling fan or thermoelectric cooler.

The approximate axial position of the sensor is indicated by the engraved line on top of the camera body. Each camera includes a USB 3.0 interface for compatibility with most computers. Included with each camera is our ThorCam software for use with Windows 7 and 10 operating systems. Developers can leverage our full-featured API and SDK.

The CS505MUP camera includes an AR-coated window that can be removed and replaced with any Ø1" (Ø25 mm) optic up to 4 mm thick. The aperture has SM1 (1.035"-40) threading for compatibility with Ø1" Lens Tubes; an adjustable C-Mount (1.000"-32) adapter is factory installed for out-of-the-box compatibility with many microscopes, machine vision camera lenses, and C-Mount extension tubes. Four 4-40 tapped holes provide compatibility with our 30 mm cage system. Two 1/4"-20 tapped holes on opposite sides of the housing are compatible with imperial Ø1" pedestal or pillar posts. These flexible mounting options, and compact size, make the CS505MUP camera the ideal choice for integrating into custom imaging systems.

Camera Mounting Features
Click to Enlarge Removing the C-Mount adapter and locking ring exposes the SM1 (1.035"-40) threading that can be used for custom assemblies using standard Thorlabs components.	Click to Enlarge A compact scientific camera with an MVL50M23 machine vision lens installed.	Click to Enlarge An SM1 Lens Tube installed using the SM1-threaded aperture.	Click to Enlarge Four 4-40 tapped holes allow 30 mm Cage System components to be attached to the camera. Pictured is our CP13 Cage Plate with C-Mount threading.

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The four-directional wire grid polarizer array is present on the sensor chip between the microlens array and the photodiodes.

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Wire grid polarizers transmit radiation with an electric field vector perpendicular to the wire and reflect radiation with the electric field-vector parallel to the wire

Polarization Features

• CMOS Sensor with Integrated 4-Directional Wire Grid Polarizer Array
• ThorCam™ Software Polarization Imaging Modes:
  • Intensity (Optical Power) / Stokes Vector S0
  • Degree of Linear Polarization (DoLP)
  • Azimuth / Angle of Linear Polarization (AoLP)
  • Unprocessed (Raw)
  • QuadView (Unprocessed, Separated by Polarization)

The CS505MUP polarization camera's image sensor incorporates an integrated, linear micropolarizer array to detect the linear polarization states within the image. Integrating the polarizers between the microlenses and photodiodes minimizes crosstalk and increases alignment accuracy between the polarizer orientations and their respective pixels compared to a polarizer array placed in front of the microlens array. The polarizer array is composed of wire grid polarizers fabricated directly on the sensor and arranged in a mosaic pattern, as shown in the drawing to the far right. These polarizers consist of an array of parallel metallic wires that transmit radiation with an electric field vector perpendicular to the wire and reflect radiation with the electric field-vector parallel to the wire, as illustrated in the drawing above. Each pixel is covered with one of four linear polarizers with orientations of -45°, 0°, 45°, or 90°. These pixel values are then used to compute the three polarization parameters for the light incident at every pixel: intensity, degree of linear polarization, and azimuth.

The images below depict the hinge on a pair of plastic safety glasses and reflection reduction on a vehicle windshield. The upper left image was acquired in intensity mode, while the upper right and lower left software screenshots were taken in DoLP and azimuth image modes. Refer to the ThorCam user guide (included with the software documentation or accessible through the Support Docs () icon below) for more information on operating the polarization camera and interacting with polarization images. Note that images are saved in the image type selected and include any processing that the image type applies. Save images in Unprocessed or QuadView modes if separate processing is necessary.

Note that high-bit-depth images like the full-resolution images available for download below may be viewed using ThorCam, ImageJ, or other scientific imaging software. They may not be displayed correctly in general-purpose image viewers.

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Intensity Image of Hinge on a Pair of Plastic Glasses
Click Here to View the Full-Resolution Image

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ThorCam Screenshot of Degree of Linear Polarization View
Click Here to View the Full-Resolution Image

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ThorCam Screenshot of Azimuth View
Click Here to View the Full-Resolution Image

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ThorCam Screenshot of QuadView

Camera Back Panel Connector Locations

For the I/O connector pin assignments, please see the Auxiliary (I/O) Connector section below.

TSI-IOBOB and TSI-IOBOB2 Break-Out Board Connector Locations

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TSI-IOBOB

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TSI-IOBOB2

TSI-IOBOB and TSI-IOBOB2 Connector	8050-CAB1 Connectors	Camera Auxiliary (I/O) Port
Female 6-Pin Mini Din Female Connector	Male 6-Pin Mini Din Male Connector (TSI-IOBOB end of Cable) Male 12-Pin Hirose Connector (Camera end of Cable)	Female 12-Pin Hirose Connector (Auxiliary Port on Camera)

Auxiliary (I/O) Connector

The camera and the break-out boards feature female connectors; the camera has a 12 pin Hirose connector, while the break out boards have a 6-pin Mini-DIN connector. The 8050-CAB1 cable features male connectors on both ends: a 12-pin connector for connecting to the camera and a 6-pin Mini-DIN connector for the break-out boards. Pins 1, 2, 3, 5, and 6 are each connected to the center pin of an SMA connector on the break-out boards, while pin 4 (ground) is connected to each SMA connector housing. To access one of the I/O functions not available with the 8050-CAB1, the user must fabricate a cable using shielded cabling in order for the camera to adhere to CE and FCC compliance; additional details are provided in the camera manual.

Triggered Camera Operation

Our scientific cameras have three externally triggered operating modes: streaming overlapped exposure, asynchronous triggered acquisition, and bulb exposure driven by an externally generated trigger pulse. The trigger modes operate independently of the readout (e.g., binning) settings as well as gain and offset. Figures 1 through 3 show the timing diagrams for these trigger modes, assuming an active low external TTL trigger.

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Figure 1: Streaming overlapped exposure mode. When the external trigger goes low, the exposure begins, and continues for the software-selected exposure time, followed by the readout. This sequence then repeats at the set time interval. Subsequent external triggers are ignored until the camera operation is halted. For the definition of the TTL signals, please see the Pin Diagrams tab.

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Figure 2: Asynchronous triggered acquisition mode. When the external trigger signal goes low, an exposure begins for the preset time, and then the exposure is read out of the camera. During the readout time, the external trigger is ignored. Once a single readout is complete, the camera will begin the next exposure only when the external trigger signal goes low.

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Figure 3: Bulb exposure mode. The exposure begins when the external trigger signal goes low and ends when the external trigger signal goes high. Trigger signals during camera readout are ignored.

Camera Specific Timing Considerations

Due to the general operation of our CMOS sensor cameras, as well as typical system propagation delays, the timing relationships shown above are subject to the following considerations:

1. The delay from the external trigger to the start of the exposure and strobe signals is typically 270 ns for all triggered modes (standard and PDX/Bulb).
2. For PDX/Bulb mode triggered exposures, in addition to the 270 ns delay at the start of the exposure, there is also a 13.72 µs integration period AFTER the falling edge of the external trigger. This is inherent in the sensor operation. It is important to note that the Strobe_out signal includes the additional 13.72 µs integration time and therefore is a better representation of the actual exposure time. Our suggestion is to use the Strobe_out signal to measure your exposure time and adjust your PDX mode trigger pulse accordingly.

External Triggering

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Figure 4: The ThorCam Camera Settings window. The red and blue highlighted regions indicate the trigger settings as described in the text.

External triggering enables these cameras to be easily integrated into systems that require the camera to be synchronized to external events. The Strobe Output goes high to indicate exposure; the strobe signal may be used in designing a system to synchronize external devices to the camera exposure. External triggering requires a connection to the auxiliary port of the camera. We offer the 8050-CAB1 auxiliary cable as an optional accessory. Two options are provided to "break out" individual signals. The TSI-IOBOB provides SMA connectors for each individual signal. Alternately, the TSI-IOBOB2 also provides the SMA connectors with the added functionality of a shield for Arduino boards that allows control of other peripheral equipment. More details on these three optional accessories are provided below.

Trigger settings are adjusted using the ThorCam software. Figure 4 shows the Camera Settings window, with the trigger settings highlighted with red and blue squares. Settings can be adjusted as follows:

• "Hardware Trigger" (Red Highlight) Set to "None": The camera will simply acquire the number of frames in the "Frames per Trigger" box when the capture button is pressed in ThorCam.
• "Hardware Trigger" Set to "Standard": There are Two Possible Scenarios:
  • "Frames per Trigger" (Blue Highlight) Set to Zero or >1: The camera will operate in streaming overlapped exposure mode (Figure 1).
  • "Frames per Trigger" Set to 1: Then the camera will operate in asynchronous triggered acquisition mode (Figure 2).
• "Hardware Trigger" Set to "Bulb (PDX) Mode": The camera will operate in bulb exposure mode, also known as Pulse Driven Exposure (PDX) mode (Figure 3).

In addition, the polarity of the trigger can be set to "On High" (exposure begins on the rising edge) or "On Low" (exposure begins on the falling edge) in the "Hardware Trigger Polarity" box (highlighted in red in Figure 4).

Example Camera Triggering Configuration using Scientific Camera Accessories

Figure 5: A schematic showing a system using the TSI-IOBOB2 to facilitate system integration and control.
While the diagram shows the back panel of our Quantalux™ sCMOS Camera, our Scientific CCD cameras can be used as well.

As an example of how camera triggering can be integrated into system control is shown in Figure 5. In the schematic, the camera is connected to the TSI-IOBOB2 break-out board / shield for Arduino using a 8050-CAB1 cable. The pins on the shield can be used to deliver signals to simultaneously control other peripheral devices, such as light sources, shutters, or motion control devices. Once the control program is written to the Arduino board, the USB connection to the host PC can be removed, allowing for a stand-alone system control platform; alternately, the USB connection can be left in place to allow for two-way communication between the Arduino and the PC. Configuring the external trigger mode is done using ThorCam as described above.

About Thorlabs Scientific Imaging

Thorlabs Scientific Imaging (TSI) is a multi-disciplinary team dedicated to solving the most challenging imaging problems. We design and manufacture low-noise, high performance scientific cameras, interface devices, and software at our facility in Austin, Texas. In addition, we are leveraging the engineering experience across Thorlabs, a vertically integrated photonics products manufacturer, to bring to market a line of integrated imaging systems, including our forthcoming, patent-pending system for whole-slide scanning.

A Message from TSI's General Manager

As a researcher, you are accustomed to solving difficult problems but may be frustrated by the inadequacy of the available instrumentation and tools. The product development team at Thorlabs Scientific Imaging is continually looking for new challenges to push the boundaries of Scientific Cameras using various sensor technologies. We welcome your input in order to leverage our team of senior research and development engineers to help meet your advanced imaging needs.

Thorlabs' purpose is to support advances in research through our product offerings. Your input will help us steer the direction of our scientific camera product line to support these advances. If you have a challenging application that requires a more advanced scientific camera than is currently available, I would be excited to hear from you.

Sincerely,

Jason Mills
General Manager
Thorlabs Scientific Imaging