Animal Cage Camera[03-JAN-25] The Animal Cage Camera (ACC) operates with our Videoarchiver to provide video that is synchronous with telemetry data to within ±100 ms. The ACC is a Power-over-Ethernet (PoE) device. It requires only one network cable for power and communication. We place the ACC in a Faraday enclosure, connect it with a shielded network cable to an Ethernet feedthrough at the wall of the enclosure, and with a shielded or unshielded network cable we connect it to an external PoE switch. We connect this switch to our data acquisition computer, and so allow the data acquisition computer to control the camera and download video the video it generates.
The Neuroplayer program makes sure that telemetry recordings are synchronized to ±50 ms with the data acquisition computer clock. The Videoarchiver makes sure that the ACC video is synchronouse with the same computer clock to within ±50 ms. The result is synchronization between video and telemetry to within ±100 ms.
The ACC provides both white and infrared illumination. Twelve white and twelve infrared LEDs are arranged on either side of the camera lense. The Scheduler component of the Videoarchiver allows us to brighten and dim the infrared and white lights automatically on separate twenty-four hour cycles of our choosing.
We can place the ACC right up against an animal cage wall, from which vantage point we can view and illumnate the entire cage with the ACC lamps and camera. Commercial webcam lenses do not provide the depth of field required to view an entire animal cage from so close to the wall, and when we move them back from the wall, reflections of their their built-in infrared lights obscure our view of the cage, so that we are forced to provide separate illumination from above or the sides.
[03-JAN-25] Low-cost webcams provide synchronization of no better than ±60 s per day. Commercial Closed Circuit Television (CCTV) systems produce video files that are supposed to span a specified length of time, but when we view these files, we find that time spanned by each file is a few seconds longer or shorter than specified. Each file has a name that gives its time of creation, and the difference in creation time from one file to the next differs by a few seconds from length of the video contained in each file. Furthermore, when we start viewing a file recorded by a CCTV system, we often find we must wait a few seconds before the picture establishes itself. As a result of these problems, we cannot rely upon synchronization between CCTV video and telemetry, nor indeed any other clock. The two chronologies can disagree by tens of seconds, and in a manner that we cannot predict or correct. Our Animal Cage Camera (ACC) is designed to solve these synchronization and viewing problems, and provide superb image quality in both light and darkness. Our ACC recordings are compatible with our Neuroplayer, so we can navigate from one location to another in our telemetry recordings and view simultaneous video automatically.
[03-JAN-25] We connect ACCs to a PoE switch, along with our data acquisition computer and our telemetry server. The video below shows how to set up a telemetry and video recording in one of our bench-top Faraday enclosures.
In the diagram below, we see an example of how ACCs and a telemetry system can be set up to operate together. Each ACC shipped from our facility will be programmed with an IP address of the form 10.0.0.x, where x is the last two or three digits of its serial number.
To operate an ACC, we must use the Videoarchiver tool in the LWDAQ Software. Follow software installation instructions in the LWDAQ User Manual. Then download and unzip the Videoarchiver Libraries. Place these libraries in a Videoarchiver folder next to your LWDAQ folder. Consult the Videoarchiver manual for further instructions on communicating with the cameras.
The ACC provides video that is synchronous with our subcutaneous transmitter recordings over any recording duration. The camera streams its video as compressed segments of length one or two seconds, depending upon the exact version of the ACC. These are received by the Videoarchiver on the data acquisition computer, where they are concatinated into videos of a precise length. When we want to view the video and telemetry signals together, we use the Neuroplayer program. We specify a directory containing the video files, as well as a directory containing the telemetry recordings. Now we can navigate through the telemetry and see the synchronous video displayed automatically.
| Version | Lens | Field of View |
Video |
|---|---|---|---|
| A3034C2-A | DSL227 | 148° | 820 × 616, 20 fps, H264, crf=27 |
| A3034C2-B | DSL215 | 180° | 820 × 616, 20 fps, H264, crf=27 |
The image quality we obtain from the ACC is superior to that of low-cost CCTV systems. The ACC lens's depth of field and sharpness of focus, and the superb exposure compensation of its image sensor, provide clear, sharp images of laboratory animals in poorly-lit cages, even when the camera is pressed up against the wall of the cage. By default, we ship the ACC with focal range 40 cm and depth of field 10 cm to infinity. We can adjust the focus for closer or farther viewing by loosening two screws on either side of the lens, rotating the lens, and tightening the screws again.
The ACC provides both white and infrared illumination that we can use to enhance image contrast, take pictures at night, or generate twenty-four hour illumination cycles. In order to view animals at night in infrared light, our lenses must not include an infrared-blocking filter. Without an infrared-blocking (NoIR) filter, the colors we record will be affected by infrared light from any source. The standard ACC does a poor job of recording colors in sunlight, or when its infrared lights mixes with ambient white light. We recommend operating the ACC in white LED or flourescent lighting during the day, and infrared at night. The Videoarchiver's Scheduler allows us to set up twenty-four hour programs of alternating white and infrared illumination.
The field of view of the ACC lens is such that it will view the entire animal cage form one end, even if we press the lens right up against the wall. When we place an ACC right up against a cage wall, we will see reflections of its white and infrared lights around the periphery of our image, but we still see the entire cage in the view between the lights.
When we move the camera five centimeters away from the cage, our reflections appear right in the middle of our view of the cage. Thus it is important for the lens to permit us to move right up to the wall. Our 148° diagonal field of view cameras are designed to illuminate their own cages while viewing from close to the wall.
The streaming latency of a video camera is the delay between movement in its field of view and the moment we see that movement displayed. We measure the streaming latency of the ACC by pointing the camera at its own live view and rotating the camera. The live view provided by the Videoarchiver sets the camera to stream uncompressed video directly to our computer. The recording latency is the delay between an event occuring in telemetry time and the event occuring in video time. We measure recording latency with the help of an Implantable Stimulator-Transponder (IST). The recording latency of the ACC is ±50 ms.
For more details of ACC operation and performance, see the A3034 Manual.
[03-JAN-25] One use of video recordings is to track the movements of individual animals. We can usually treat animals as blobs in image analysis, and track them with blob-tracking algorithms. When we have more than one animal in a cage, the animals are near-identical in appearance, the animals often vanish beneath obstacles, and often cluster together, video blob tracking fails. But if we have Subcutaneous Transmitters (SCTs) implanted in our animals, we can use an Animal Location Tracker (ALT) to measure the approximate movements of each animal, compare these approximate movements to those of the blobs produced by blob tracking, and so determine which blob corresponds to which transmitter. We call this application of ALT tracking information disambiguation of video blob tracking. This disambiguation is possible because the ACC videos are well-synchronized with the our SCT telemetry system.
There are many groups working on the video blob-tracking problem. Some of our customers are well-satisfied with their commercially-purchased blob-tracking software, such as Ethovision Video Tracking. We produced our own blob-tracking software some years ago. You will find our open-source software in our Video Blob Tracking repository. An example of its successful application is available here.
[03-JAN-25] We sell the ACC for US$1200 each, with no volume discount. If you can tolerate ±60 s synchronization between telemetry and video, you may prefer to use a Telemetry-Compatible Webcam (TCW). A TCW is any webcam we have tested for compatibility with our telemetry system. Only power over ethernet (PoE) cameras are compatible with our telemetry system. But some PoE webcams generate so much noise that they interfere with telemetry reception. In one case, we observed that telemetry reception dropped to 50% when our customer turned on an expensive commercial camera's infrared lights. To avoid such problems, purchase one of our TCWs and follow the manufacturer's instructions to set up the cameras. Although we guarantee these cameras are compatible with our telemetry system, we do not warranty their performance in any way, nor do we offer any assistance in their configuration or use.
Test_21AUG20.zip: Fifty-five 20-s videos with accompanying telemetry from two transmitters mounted on mouse toys.
Test_13JUN19.zip: Four 600-s videos with accompanying telemetry from an animal with an Implantable Sensor with Lamp (ISL). We see the light flashing, and unwanted lamp artifact in the recorded EEG signal, which is perfect for checking synchronization of video.
Test_05JUN18.zip: Ten 60-s videos with accompanying telemetry from four transmitters being handled in a Faraday enclosure.
