Cameras & Imaging

Terms, Definitions, Etc

CMOS vs CCD

In short, both are imaging sensors that convert light into electrical charge. However, they have differing characteristics. For more detail see this.

CMOS

• Every pixel transmits its charge in parallel
• Higher FPS
• Lower noise
• Smaller

CCD

• Every pixel's charge transferred through limited number of output nodes
• More sensor surface area for light capture

Performance in low light

One of the primary requirements for our camera is low-light performance. This article explains how to compare different cameras (Pt Grey cameras, at least).

Video Imaging

Video cameras onboard the sub will primarily be used for navigation and obstacle detection. However, they maintain a secondary purpose of recording each underwater excursion.

Requirements

Numbered by importance:

1. Cost - I’m bankrolling this thing myself!
2. Light sensitivity
3. FPS - As out primary method of obstacle detection and navigation, anything more than 60 FPS suffices.
4. Latency - The higher the latency, the more of delay on which the sub operates.
5. Controls - It should have manual controls for every setting, but also great auto-controls. This way, I don't need to fiddle with camera setting control software at the start, but can later.
6. FOV - The larger the field of view, the more the sub sees. Duh.
7. Interface - One wire for power and data is ideal. I choose USB 3 over ethernet because I’m afraid to add network latency.
8. Size/Weight - The smaller and lighter, the better.
9. Temperature - How hot will the interior of the hull get without batteries in it?

Nice to haves

• Onboard recording
• Waterproofing

Candidates

• Point Grey
  • https://www.ptgrey.com/grasshopper3-23-mp-color-usb3-vision-sony-pregius-imx174
  • https://www.ptgrey.com/blackfly-23-mp-color-usb3-vision-sony-pregius-imx249
  • https://www.ptgrey.com/grasshopper3-50-mp-color-usb3-vision-sony-pregius-imx250
  • https://www.ptgrey.com/grasshopper3-32-mp-color-usb3-vision-sony-pregius-imx252
• Matrix Vision
  • https://www.matrix-vision.com/USB3-vision-camera-mvbluefox3-2.html?camera=mvBlueFOX3-2024C
  • https://www.matrix-vision.com/USB3-vision-camera-mvbluefox3-2.html?camera=mvBlueFOX3-2024aC
  • https://www.matrix-vision.com/USB3-vision-camera-mvbluefox3-2.html?camera=mvBlueFOX3-2051C
  • https://www.matrix-vision.com/USB3-vision-camera-mvbluefox3-2.html?camera=mvBlueFOX3-2032C
• IDS Imaging
  • https://en.ids-imaging.com/store/produkte/kameras/ui-3060cp-rev-2.html
  • https://en.ids-imaging.com/store/produkte/kameras/ui-3260cp-rev-2.html
• Others
  • http://www.theimagingsource.com/en_US/products/cameras/usb-cmos-ccd-color/dfk23ux174/, $600
  • http://subcimaging.com/product/1cam-3d/ (too expensive, $30k)
  • http://www.oemcameras.com/enclosed-cameras/, $various

Still Imaging

Any still imaging devices onboard will only operate as high definition frame grabbers for scenes of interest (or merely intermittently).

Requirements

Numbered by importance:

1. Cost - Again, my money.
2. Controls - Same as with video imaging.
3. Resolution - More.
4. Size/Weight - Once again, the smaller and lighter, the better.
5. Temperature - Most cameras will operate within the NYC oceans temperature range (~0C to ~25C)