Using LUCID's TRI054S IMX490 in ArenaView

Introduction

The Triton TRI054S featuring the IMX490 (BSI) back-illuminated stacked CMOS sensor allows for simultaneous 120 dB HDR imaging and LED flicker mitigation. With the large 5.4 MP, 2880 x 1860 px resolution this camera enables wide-angle shooting in both daytime and nighttime for Advanced Driver Assistance Systems(ADAS) / Autonomous Driving. This camera model is also well suited for other applications that demand very high HDR imaging such as electrical fuse inspection; high contrast medical imaging; live visible welding analysis; as well as other ITS applications.

These instructions explain how to use the TRI054S-CC in ArenaView.

Requirements

Triton TRI054S-CC camera
ArenaView v1.0.27.0 or newer

Setting up cameras in ArenaView

Step 1: Initial Setup

Please make sure you have read and completed the initial setup section found in the Arena SDK documentation. In particular, make sure you have turned on jumbo frames and set your receive buffer size.

Step 2: Connect Camera and Launch ArenaView

Once Arena SDK is installed, the system is properly configured, and the camera is plugged in and powered, you can open ArenaView in Windows and toggle the connect button.

Step 3: Open Pixel Format Options Window

Open the Pixel Format Options window by clicking View -> Toolbars -> Options.

Step 4: Acquire Images

Press the button to acquire a single image in ArenaView.
Press the button to continuously acquire images in ArenaView.
Press the button to stop acquisition and close the current tab.

Pixel Formats

The TRI054S supports up to 24-bit Bayer and Mono pixel formats as well as 24-bit on-camera processed formats. Change the camera’s pixel format in the Features window, under Image Format Control -> Pixel Format.

You must stop image acquisition before changing the Pixel Format selection.

Imaging with TRI054S IMX490

If using the TRI054S IMX490 indoors, the image may appear dark because the default Exposure Time of the camera is set to a value that is intended to be reasonable for many outdoor settings.

You can use a higher bit depth pixel format and choose to display the brighter parts (the higher pixel values) of the image data. See the Bit Depth Display in ArenaView or LUT Control sections for further information.

The automatic exposure algorithm is turned off by default on the TRI054S IMX490.

HDR Processing

The TRI054S IMX490 sensor features the capability to output HDR images. This sensor function captures four images at different Exposure Time and Gain settings and outputs a single combined image, allowing the user to take advantage of the wide-ranging illumination conditions from low to high.

The TRI054S IMX490 has default analog gains programmed which provide linear 24-bit HDR output with over 120dB of dynamic range. The default values should be close to optimal for most use cases. However advanced users may wish to customize the HDR Channel Exposure Time and Gain of each channel, as explained below.

You can customize HDR controls by navigating to the camera’s HDR Control category.

HDR Output

You can choose which HDR image the camera outputs by changing the HDR Output node.

HDR: The camera generates a 24-bit HDR image by combining the 4 channels
Channel 0: Outputs the 1st image used in the HDR output. This image is collected from high-sensitivity sub pixel with high conversion gain (most sensitive).
Channel 1: Outputs the 2nd image used in the HDR output. This image is collected from high-sentitivity sub pixel with low conversion gain.
Channel 2: Outputs the 3rd image used in the HDR output. This image is collected from low-sensitivty sub pixel, where SNR is prioritized.
Channel 3: Outputs the 4th image used in the HDR output. This image is collected from low-sensitivity sub-pixel, where illuminance is prioritized (least sensitive).

Set HDR Output to Channel 0, 1, 2, or 3 to view a single uncombined image.

You must stop image acquisition before changing the HDR Output selection.

HDR Tuning Enable

When HDR Tuning Enable is False, you can set the Exposure Time node which changes the HDR Channel Exposure Time of all four channels at once. You cannot change the Gains of the channels in this setting.

You can customize each HDR image’s Exposure Time and Gain with the following steps:

Set HDR Tuning Enable to True
Set the HDR Tuning Channel Selector to the desired image (0-3)
Change the image’s HDR Channel Exposure Time
Change the image’s HDR Channel Analog Gain or HDR Channel Digital Gain

HDR Image Enhancement Enable

The TRI054S IMX490 sensor can perform image processing for the HDR image which include:

Dark shading compensation (assists in image uniformity)
Motion-based artifact compensation (reduce artifacts where moving subjects were detected)
False color compensation (reduces false colors where motion-based artifact compensation is applied)
Dynamic spot pixel correction
Noise reduction

This processing is only applicable for the HDR image, in other words when HDR Output = HDR.

To turn off this additional processing, set HDR Image Enancement Enable = False.

HDR Digital Clamping Enable

The TRI054S IMX490 sensor also has a Analog Clamp and Digital Clamp feature to reduce black level fluctuations. The sensor compensates for black level by using the information of the preceding frame and the current frame.

The sensor’s Analog Clamp function occurs on after the ADC step and cannot be disabled. To turn off the Digital Clamp function, set HDR Digital Clamping Enable to False.

LED Flicker Mitigation

Traditional HDR output techniques combine low and high exposures of the same pixels. The short exposure would be used to capture the bright parts of a scene, but the output can result in flickering artifacts.

The TRI054S IMX490 sensor is equipped with low-sensitivity subpixels to reduce LED flickering. This allows longer exposures to be used while still averaging out the LED flicker. This technique is applied when HDR Output is set to HDR.

Incorrectly setting the HDR Exposure Time and Gain of each channel can cause HDR artifacts such as non-linear response, color banding or other color artifacts, and HDR output which does not use the full 24-bit output range.

Bit Depth Display in ArenaView

When capturing in an image in ArenaView, it will process the image and display it as a BGR8 (8-bits per color channel) image. When using a pixel format that is greater than 8-bits you can use ArenaView’s Bit Depth display option to choose which bits are shown in your image.

The following instructions will explain how to use ArenaView’s Bit Depth display option.

1. Open the Bit Depth options by going to the Options window and selecting the Bit Depth tab.

2. Enable the Bit Depth control and use the slider in the Bit Depth options to choose which bits to display. The bits that are displayed in the image highlighted on screen in green.

Use Arena SDK code similar to the following on an image to achieve the same effect:

// In BayerRG24 pixel format
Arena::IImage* pImage = pDevice->GetImage(2000);
double offset = (double)pImage->GetBitsPerPixel() - 1.0;
Arena::IImage* pScaled = Arena::ImageFactory::SelectBitsAndScale(pImage, 8, offset - 20.10);

LUT Control

A Lookup Table (LUT) allows the user to remap an input pixel value to a different output pixel value. There are two options available for a lookup table which are explained below.

Using a Camera LUT

The TRI054S features an on-camera LUT to allow mapping of input pixels to output pixels.

When using a single channel output image, you can map 12-bit raw sensor pixel values to 12-bit user-specified pixel values. Users input values for the even indices including the last index 4095 while averaging is used to calculate rest of the odd indices.

When using an HDR output image, you can map 24-bit raw sensor pixel values to 24-bit user-specified values. 4096 knee points are provided in the mapping. These knee points spread evenly in the input pixel space. Pixel values between knee points are mapped with interpolation.

The following instructions demonstrate how to define a Camera LUT with ArenaView:

1. Open the Camera LUT options by going to the Options window and selecting the LUT tab.

2. Select points in the graph to quickly map an input pixel value to an output pixel value.

Press the button to apply the LUT to the camera.

The TRI054S IMT490 has a pre-defined Camera LUT that is enabled by default. This LUT is meant to look reasonable for many outdoor settings.

On the camera, set LUT Enable to True to enable the Camera LUT.

You must stop image acquisition before changing LUT Enable.

LUT Tone Mapping

The dynamic range of a display is narrower than the the dynamic range of the TRI054S IMX490. The LUT Tone Mapping control performs tone mapping to allow the brightness of the images to be suitable for display based on the histogram of the captured image. Several Gamma curve tone mapping options are available to choose for display. A Linear tone mapping option is available as well.