Question - does the CBMS use radar, camera or both to determine if an obstacle exists?
CMBS uses both the radar and camera.
For a visual these working together, check out
this (non-Honda) video which shows how radar and camera look individually AND when used in "fusion" together. The combined systems improve detection BUT also requires more programming choices from Honda to tune the inputs.
To share some thoughts / observations for further input from this group:
- LKAS, RDM, and Sign Recognition use ONLY the Camera.
- CMBS and ACC/LSF rely on BOTH Radar and Camera (like the "fusion" method shown in video).
- CMBS has the highest number of 'conditions and limitations' among Honda Sensing options, and most of the limitations relate to camera (lighting, pedestrian detection).
Taking the CMBS 'heavy camera reliance' together with the
'outsourcing to improve pedestrian detection' article andrew28 shared - could CMBS/"Brake Alert" be oversensitive because Honda tuned the system to favor camera input (pedestrian risk detection) instead of radar input (physical object detection) - ?
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If helpful, below is a topline summary comparison from re-reading the Honda Sensing section of Manual. CMBS is the only one that is "multi-tiered" by speed, object direction, and specifically calls out pedestrian detection.
CMBS = Radar + Camera, starting at speeds >3 mph
- for 3 to 62 mph: monitors for stationary, oncoming, OR same direction
- for 62+ mph: monitors same direction only
- turns on every time power system starts, regardless of prior selection
- camera is designed/used for pedestrian detection (p484)
- 47 'conditions and limitations' listed, with more than half (~30) being camera-specific (e.g. temperature, pedestrian) or lighting-related (e.g. shadow, contrast)
ACC/LSF = Radar + Camera, for speeds up to 90 mph
- retains "off" setting if selected during prior drive
- 23 'conditions and limitations' listed, of which majority are radar-related (only ~4 camera related ones, so less dependence/risk on camera)
LKAS = Camera only, for speeds 45-90 mph
- system suspends when turn signals or brake pedal are activated, or wipers are continuously running
- 26 'conditions and limitations' listed, of which most (~22) are camera-related
RDM = Camera only, for speeds 45-90 mph
- system suspends when turn signals or wipers are continuously running, or when there's active acceleration, braking or steering
- remembers "off" setting if selected during prior drive
- 27 'conditions and limitations' listed, of which most (~22) are camera-related
Sign Recognition = Camera only
- camera needs to be recalibrated after windshield is replaced
- 30 'conditions and limitations' listed, almost all of which are camera-related