Hand recorder: ask for Daylight when sunlight comes in; the cameras can't tell it

The first daylight round (dataset PR #5, a room with big sunlit windows) read 2.38 ambient IR
and was labelled indoor: the windows are a small part of each picture, so the dark frames' mean
barely moves. The checklist no longer says the cameras tell daylight themselves, and the docs
say how review corrects the label (hub_review.py lighting) from how much hands stand out.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

hands/rec/DESIGN.md

@@ -283,7 +283,7 @@ Before section 7: "Put on both controllers and tighten the straps". Before secti
 - **Hands seen:** from the hands file. A hand counts as seen if its flags match the side and the file is fresh (publish within 0.3 s). Prompts with `hands` set show the `hands` chips. If an asked-for hand is lost for more than 1.5 s, the note says "I can't see your left hand: bring it into view".
 - **Controller tracking:** in sections 8 and 9, `devices` is polled once a second. A result other than 200 for more than 1 s says "The left controller lost tracking: turn your palm slightly toward you". Each such stretch goes into `prompts.jsonl` as `feedback` with `"controller": {...}`.
 - **Lighting, measured:** the checklist page measures the light when it opens, starting ft-camd (`frametop-handrec-camd.service`) if nothing runs it; the window stops it again on quit if it started it. The mean of every mono camera's `mean` and `dark_mean` from the ring (`hands/tools/ring.py` layout; struct only, no numpy) is compared with the person's earlier sessions. If it matches an earlier round's within 15%, the window says so before starting.
-- **Lighting label:** "Measured by the cameras" is the default. `ambient_ir`, the mono cameras' mean `dark_mean` (the room's infrared), labels the round `daylight` from 6.0 and `indoor` below (`session.classify_lighting`). Lamps and LEDs give off hardly any infrared, so a dim room and a lit one read about the same (1.8 by one lamp, 2.2 in a lamp-lit room) and the cameras can't tell them apart; the person can pick dim, room or daylight instead (`source: "picked"`). The 6.0 threshold is a guess until a daylight round is measured.
+- **Lighting label:** "Measured by the cameras" is the default. `ambient_ir`, the mono cameras' mean `dark_mean` (the room's infrared), labels the round `daylight` from 6.0 and `indoor` below (`session.classify_lighting`). Lamps and LEDs give off hardly any infrared, so a dim room and a lit one read about the same (1.8 by one lamp, 2.2 in a lamp-lit room) and the cameras can't tell them apart; the person can pick dim, room or daylight instead (`source: "picked"`). The 6.0 threshold was a guess, and the first daylight round (dataset PR #5, 2026-10-05, a room with big sunlit windows) read 2.38 and was labelled `indoor`: the windows are a small part of each picture. So the checklist now asks people to pick Daylight when sunlight comes in, and the maintainer corrects the label in review (`hub_review.py lighting`) when hands stand out far less than in lamp light (PR #5: hands a median 1.15x as bright as their surroundings, against 1.5-1.7x).
 
 ### Camera check
 

hands/rec/main.qml

@@ -362,7 +362,8 @@ Kirigami.ApplicationWindow {
                     wrapMode: Text.Wrap
                     opacity: 0.7
                     text: "Each round in a different light helps the most: dim, a normal room, daylight. The cameras "
-                          + "tell daylight from indoor light themselves; to say dim or a normal room, pick it here."
+                          + "can't tell daylight on their own (a sunlit room has measured as indoor light), so if "
+                          + "sunlight comes into the room, pick Daylight here; dim or a normal room the same way."
                 }
                 Kirigami.InlineMessage {
                     Layout.maximumWidth: Kirigami.Units.gridUnit * 26

hands/rec/session.py

@@ -292,7 +292,7 @@ def similar_lighting(base_dir, lighting):
     return None
 
 
-DAYLIGHT_IR = 6.0   # ambient IR (the mono cameras' mean dark_mean) from which it's daylight
+DAYLIGHT_IR = 6.0   # ambient IR (the mono cameras' mean dark_mean) from which it's daylight; see classify_lighting
 
 
 def ambient_ir(ring):
@@ -306,7 +306,12 @@ def ambient_ir(ring):
 def classify_lighting(ring):
     """"daylight" or "indoor" from the room's infrared light, "" if it can't tell. Sunlight
     carries a lot of infrared; lamps and LEDs hardly any, so a dim room and a bright one read
-    about the same (2026-10: 1.8 by one lamp, 2.2 in a lamp-lit room) and aren't told apart."""
+    about the same (2026-10: 1.8 by one lamp, 2.2 in a lamp-lit room) and aren't told apart.
+    Nor does a sunlit room reliably: the first daylight round (dataset PR #5, big sunlit windows)
+    read 2.38, since the windows are a small part of each picture and the mean barely moves. So
+    "indoor" means "no strong daylight on the cameras", and the window asks people to pick
+    daylight themselves. What did show it there: hands only ~1.15x as bright as their surroundings
+    (1.5-1.7x in lamp-lit rooms), which needs hands in view, so it's measured on the dataset side."""
     ir = ambient_ir(ring)
     if ir is None:
         return ""