Domain: Engineering — Optical Engineering
Target concept: Imaging Exposure Experiment

Video generation prompt: Set up a focal plane array CCD imaging system, place a colored object in front of the system, adjust the exposure time (1ms → 10ms → 100ms), and observe the imaging effect on the CCD display. Overexposed regions are marked in red, underexposed regions are marked in blue, and normally exposed regions are marked in their original color.

Evaluation guide:
Target Concept: Exposure time in CCD imaging is the controlled integration duration determining photon-derived pixel intensity; its manipulation directly governs whether scene radiance maps to underexposed (noise-dominated), normally exposed (linear-response), or overexposed (saturated) digital values. Minimum mechanistic assumptions: (1) CCD pixels respond linearly to incident photons within full-well capacity; (2) false-color overlay is a deterministic, threshold-based visualization (blue <5%, red >95%, else original); (3) object reflectance and illumination are invariant across exposures. Phased Storyline: [Phase 1: Baseline] 1ms exposure → insufficient integration → most pixels fall below noise floor → blue dominates shadows/textures, original colors lost. [Phase 2: Optimal] 10ms exposure → ideal integration → pixel values span usable dynamic range → original colors preserved with full detail. [Phase 3: Saturation] 100ms exposure → excessive integration → full-well overflow in bright zones → red floods highlights, compressing detail, while only deepest shadows retain blue. Visibility constraints: Observer must view false-color-coded monitor (not raw sensor), with exposure labels temporally locked to frame onset; verification requires comparing spatial extent and proportion of red/blue overlays across frames, not absolute brightness, to infer exposure status.

Manual:
Imaging Exposure Experiment Demonstration Instructions
I. Basic Demonstration Information
Demonstration Title: CCD Imaging Exposure Effect Visualization (1ms → 10ms → 100ms) Demonstration
Subject: Engineering - Optical Engineering - Imaging Exposure Experiment
Demonstration Purpose: By setting up a focal plane array CCD imaging system, placing a colored object (e.g., a red-green-blue patterned card with high-contrast regions) in front of it, and sequentially adjusting exposure time from 1ms → 10ms → 100ms, this demonstration visually reveals how exposure time governs pixel intensity saturation; it enables direct observation of overexposed (red-marked), underexposed (blue-marked), and normally exposed (original-color) regions on the CCD display; and it establishes foundational visual recognition skills for exposure-based feature segmentation in optical imaging systems.

II. Demonstration Carrier/Equipment
Core Carrier: Focal plane array CCD imaging system (monochrome or color CCD with real-time false-color overlay capability), standardized colored test object (e.g., ISO 12233 chart variant with red/green/blue patches and grayscale steps, placed at fixed distance ~50 cm)
Auxiliary Equipment: Adjustable exposure control interface (software or hardware dial), calibrated monitor displaying live CCD output with real-time false-color encoding: red = pixel value > 95% saturation (overexposed), blue = pixel value < 5% saturation (underexposed), original color = 5–95% (normally exposed); stable optical bench with vibration isolation; uniform ambient illumination (no direct glare on object or lens).

III. Demonstration Content Description
Layout: Mount CCD system on optical bench; position colored test object perpendicular to optical axis at fixed working distance. Connect CCD output to monitor with false-color overlay enabled. Ensure no motion blur — object and camera are static throughout.
State Control: Maintain constant illumination, focus, aperture (fixed f-number), and gain (unity/0 dB) — only exposure time varies. System must be in manual exposure mode; auto-exposure and HDR modes disabled.
Sequence Protocol: Perform three discrete exposures in strict ascending order: (1) Set exposure = 1ms → acquire & hold frame; (2) Set exposure = 10ms → acquire & hold frame; (3) Set exposure = 100ms → acquire & hold frame. Each frame remains displayed ≥2 s for observation before transition.

IV. Observation of Core Phenomena
1ms Exposure Frame:
– Dominant visual state: large blue-marked regions (especially in dark patches/shadow areas); minimal red; most colored patches appear desaturated or near-black; original colors visible only in brightest highlights.
– Visual verification features: Blue dominates >70% of object area; red appears only as tiny specks on specular highlights; overall image is low-contrast and dim; false-color map clearly separates underexposed (blue) from nominal (original) zones.
10ms Exposure Frame:
– Balanced visual state: blue regions shrink significantly (now <20% of object area); red regions remain rare (<5%); majority of object displays original colors with accurate hue/saturation; grayscale steps show smooth progression without clipping.
– Visual verification features: Original-color regions dominate central patches (e.g., red square retains red hue, green square retains green hue); blue confined to deep shadows; no red in midtones — confirms optimal exposure window.
100ms Exposure Frame:
– Dominant visual state: widespread red-marked regions (especially in bright/midtone patches); blue nearly absent; original colors vanish from most areas except deepest shadows; highlights are clipped and non-informative.
– Visual verification features: Red covers >60% of object (e.g., entire red/green patches turn solid red; white zones fully saturated red); blue persists only in extreme shadow corners; loss of chromatic detail confirms overexposure.
Characteristic Stability & Causal Transition:
– Progressive, monotonic change: increasing exposure → expanding red → shrinking blue → compression of dynamic range → irreversible highlight clipping.
– No flicker, jump, or spatial misalignment between frames: same object geometry, consistent false-color mapping logic, identical field-of-view across all three exposures.

V. Summary of Key Knowledge Points and Principles
Core Concept Definition: Exposure time is the duration during which photons integrate on CCD pixels; it directly determines signal amplitude per pixel. Underexposure occurs when integrated charge < read-noise floor (rendering data unrecoverable); overexposure occurs when charge exceeds full-well capacity (causing saturation and clipping). False-color overlay is a diagnostic visualization tool mapping pixel intensity to intuitive color codes.
Principle of Visual Feature Recognition Comparison:
– Human observers identify exposure status not by absolute brightness, but by *spatial distribution* and *proportion* of red/blue overlays relative to object structure.
– Recognition relies on comparative contrast: e.g., “red spreading from highlight into midtone” signals overexposure onset; “blue encroaching from shadow into texture” signals underexposure.
– Critical inference: Normal exposure is defined *relationally* — where original color fidelity coexists with full shadow-to-highlight detail retention.

VI. Demonstration Precautions
– Must disable all automatic corrections (auto-gain, auto-white-balance, gamma correction) to preserve raw exposure response.
– Monitor must use linear LUT (no tone mapping) so false-color thresholds (5%, 95%) correspond precisely to digital counts.
– Object must contain known high-dynamic-range features (e.g., black-to-white gradient + saturated color patches) to unambiguously trigger all three exposure states.
– Exposure transitions must be discrete (not ramped) and labeled on-screen (e.g., “t=1ms”, “t=10ms”, “t=100ms”) to anchor temporal causality for learners.
– Total demonstration duration ≤10 s: 2 s per frame × 3 frames + 1 s transition labels = 7–9 s total.

Prompt Grounding rubric:
level_1: No CCD imaging system is shown, no colored test object appears, no exposure-time labels are shown changing, and no red/blue overlay coloring appears anywhere on screen. The video does not depict any part of the described experiment.
level_2: A camera-like device or monitor appears, but the object in front of it has no color (monochrome or absent); exposure-time labels (1ms, 10ms, 100ms) may appear but nothing about the image visibly changes between them; no red or blue overlay markings appear anywhere, or the same color is used for both bright and dark regions.
level_3: The CCD system and a colored test object are both shown, roughly positioned as described; the three exposure labels appear in the correct order (1ms, then 10ms, then 100ms); red and blue overlay regions appear somewhere in at least one frame, but overlay coloring is missing or clearly wrong in at least one of the other two frames (e.g., the 1ms frame shows no blue at all, or the 100ms frame shows no red at all).
level_4: The CCD system, the colored test object, and the three exposure labels (1ms, 10ms, 100ms shown in that order) are all present; each of the three frames shows some red overlay, some blue overlay, and some original-color region, changing recognizably across the three exposures; minor flaws such as slight object distortion, a brief label flicker, or an uneven hold time on one frame do not prevent the viewer from telling the three frames apart.
level_5: The focal-plane-array CCD system (visible sensor housing, lens, and cable) and a stationary, multi-colored test object are clearly shown; the three frames (1ms, 10ms, 100ms) appear in strict order with on-screen labels that change exactly when each new frame begins; each frame visibly shows a different balance of red, blue, and original-color regions from the other two; overlay regions have clear, legible boundaries rather than being smeared or illegible.

Scientific and Causal Correctness rubric:
level_1: The image's brightness or color response has no link to the stated exposure time: for example the 100ms frame looks darker than the 1ms frame, or red/blue marks appear in places that contradict how bright those spots actually look, or all three frames look identical or run in reverse of what longer exposure should produce.
level_2: Exposure labels are shown but the overlay response contradicts basic exposure physics: the 1ms (shortest exposure) frame shows heavy red saturation, or the 100ms (longest exposure) frame shows overlay dominated by blue instead of red; a colored patch changes to a completely different hue between frames (e.g., a red patch turns cyan at 10ms) with no explanation.
level_3: Brightness clearly increases with exposure time overall, but the red/blue mapping is only loosely tied to it: for instance red appears in a shadow region at 100ms while blue lingers in a mid-brightness region at 1ms, or the original object colors look shifted (e.g., a green patch reads as yellow); the link between longer exposure and a larger red-marked area is present but inconsistent across the three frames.
level_4: Longer exposure visibly produces more red-marked area and less blue-marked area, in that order across 1ms, 10ms, 100ms; the object's original colors read correctly in the 10ms frame; red overlay grows outward from the brightest regions and blue overlay shrinks back into the darkest regions as exposure increases; only small deviations remain, such as a slight color cast in the 100ms frame or a small red patch bleeding a little past where the brightest object region actually is.
level_5: The three frames follow the exposure-color relationship exactly as described: at 1ms, blue overlay covers most of the darker/textured regions and colors look mostly washed out; at 10ms, the object's original colors are visible with clean detail and only small red or blue patches at the very brightest or darkest spots; at 100ms, red overlay covers the bright and mid-tone regions that previously showed original color, while only the very darkest areas still show blue; the boundary between red/blue/original-color regions in each frame lines up with where the object is actually brightest or darkest, matching a roughly 5% (blue cutoff) / 95% (red cutoff) split with no unexplained hue shifts.

Spatiotemporal Consistency rubric:
level_1: The object or the CCD/monitor jumps to a different location or size between frames, or the display flickers wildly or spins; exposure labels appear behind the object or in the wrong screen layer; the three frames have different aspect ratios or camera angles; the clip cuts abruptly between frames with no visible hold or fade.
level_2: The object and CCD mostly stay put but visibly grow, shrink, or rotate between frames; a label shows the wrong exposure time for the frame it's attached to (e.g., '10ms' appears during the 1ms frame); the field of view or image resolution visibly changes between frames; transitions between frames look jarring or stutter instead of flowing; the red/blue overlay noticeably drifts away from the object's edges.
level_3: The object and CCD setup look stable in position and size; exposure labels are correctly placed and change at the right time; there may be a small amount of visible drift between the overlay coloring and the object's edges, or brief jitter in a label's position, and the three frames are held for noticeably uneven lengths of time, but the 1ms → 10ms → 100ms order is preserved.
level_4: The object's position, size, and orientation look identical across all three frames; the red/blue overlay tracks the object's outline closely with no visible drift; exposure labels sit in a fixed spot, stay crisp, and are easy to read; the three frames are held for roughly equal, consistent durations; the video moves between frames with a clean fade or cut rather than a jarring jump.
level_5: The camera framing, object position, and lighting look completely unchanged across all three exposures; the red/blue overlay boundaries visibly track the object's actual bright/dark regions with no drift or misalignment in any frame; the three frames are held for clearly equal-looking durations with a smooth, consistent transition between each; there is no visible distortion, jitter, or mismatched timing anywhere in the sequence.