Binning Introduction

Binning (pixel binning) is a common technique in industrial cameras to trade spatial resolution for sensitivity. Simply put, it combines several adjacent pixels on the sensor into one larger pixel.

Imagine an 8×8 chessboard where each square represents one pixel. With 2×2 binning, every four adjacent small squares are merged into one large square. The chessboard becomes 4×4. The number of squares decreases, but each "super‑pixel" has a larger light‑collecting area.

Core benefits of Binning:

• Higher sensitivity — Each merged "super‑pixel" collects more photons and delivers stronger signal
• Improved Signal‑to‑Noise Ratio (SNR) — Signal increases while noise rises more slowly for cleaner images
• Higher frame rate — Fewer output pixels reduce data transfer and processing load

The obvious trade‑off is reduced image resolution. After 2×2 binning, width and height are each halved, and total pixel count drops to 1/4 of the original.

2 How Binning works on C15550‑22UP

The C15550‑22UP supports independent horizontal and vertical Binning control, and provides two merging modes. Users can configure Binning behavior flexibly via GenICam parameters.

2.1 Binning Selector

The C15550‑22UP includes two internal Binning engines:

BinningSelector determines which engine is controlled by BinningHorizontal and BinningVertical. For C15550‑22UP, Sensor‑level Binning is used by default.

2.2 Binning Factor

BinningHorizontal and BinningVertical control binning multiplier for horizontal and vertical directions respectively:

Example: Raw sensor resolution is 2048×2048. Setting H‑Binning=2, V‑Binning=2 produces output resolution of 1024×1024.

2.3 Binning Mode (Sum)

How are multiple pixel values combined into one output? C15550‑22UP supports Sum mode:

Simple numeric example:

Assume four adjacent pixels with values: 1000, 1200, 1100, 1300:

Sum mode delivers higher output values for improved sensitivity. However, strong raw signals may exceed 65535 and cause saturation. Average mode keeps output values within the original value range without extending dynamic range while averaging out noise.

2.4 Important Note: Vertical Mode follows Horizontal Mode

On C15550‑22UP, BinningHorizontalMode is read‑write (RW), while BinningVerticalMode is read‑only (RO). Vertical binning mode automatically follows horizontal settings and cannot be configured independently. If BinningHorizontalMode = Sum, vertical binning also uses Sum automatically.

3 Where Binning occurs inside the camera

Binning processing runs inside the camera before image data is sent to PC:

Sensor → Photoelectric conversion → [Binning merge] → ADC sampling → Dark correction → Pixel gain correction → CoaXPress output → PC

This means:

• Merging runs in sensor/FPGA hardware with no CPU load on host PC
• Images transmitted to PC are already binned at reduced resolution
• Binning cannot be software‑undone to restore original resolution
• Binning affects valid ranges for Width/Height/OffsetX/OffsetY parameters

4 Practical Effect Demonstration

4.1 Scenario 1: No Binning (Baseline)

Settings: BinningHorizontal = 1, BinningVertical = 1

Effect: Full native sensor resolution, each pixel output independently.

Use case: Inspection tasks requiring maximum spatial resolution e.g. tiny defect detection.

4.2 Scenario 2: 2×2 Binning + Sum Mode

Settings: BinningHorizontal = 2, BinningVertical = 2, Mode = Sum

Effect: Output resolution halved (1024×1024). Each output pixel equals sum over a 2×2 pixel region.

Visual behavior: Image brightness increases significantly (~4×), making faint signals visible. Strong input signals may saturate (pixel value clamped at 65535).

Use case: Extremely low‑light applications such as single‑molecule fluorescence for maximum sensitivity.

5 Important Notes

5.1 Acquisition must be started

When TimerTriggerSource is set to FrameEnd or ExposureEnd, timer events depend on running frame acquisition. If acquisition is not started (AcquisitionStart), no frame events will be generated, timers never trigger, and no pulses appear on timing outputs.

Correct workflow: Configure parameters → AcquisitionStart → Measure with oscilloscope

5.2 Explicit LineSource configuration required

This is a frequently‑missed step. Configuring Timer0 parameters alone is insufficient. You must route Timer0Active signal to physical output:

LineSelector = Line1 → LineSource = Timer0Active

If omitted, Timing 1 outputs default signal (likely UserOutput) instead of timer pulses.

Watch output polarity (LineInverter)

TimerActive is high‑active by default (idle = low level, active = high level). Output polarity can be inverted via LineInverter:

• LineInverter = False: Idle at 0 V, pulse at 3.3 V
• LineInverter = True: Idle at 3.3 V, pulse at 0 V

If oscilloscope shows constant 3.3 V idle level, first check whether LineInverter is enabled.

Select timer before modifying parameters

TimerDuration, TimerDelay, TimerTriggerSource are indexed by TimerSelector. After switching timer index, re‑verify these three parameters; values do not auto‑refresh.

Avoid excessive TimerDuration

If TimerDuration exceeds frame period, the timer may get re‑triggered before completion and hold constant high output. Keep Duration ≤ 1/2 of frame period for reliable operation.

6 Configuration in ImgGrab

Example: Configure Timer0 to output frame‑sync pulses on Timing 1:

Step 1: Signal Routing (DigitalIOControl)

1. LineSelector = Line1
2. LineInverter = False
3. LineSource = Timer0Active

Step 2: Timer Parameters (CounterAndTimerControl)

1. TimerSelector = Timer0
2. TimerTriggerSource = FrameEnd
3. TimerDelay = 0 µs
4. TimerDuration = 1000 µs

Step 3: Start Acquisition

1. AcquisitionMode = Continuous
2. Click AcquisitionStart
3. Verify frame rate and live image streaming

Step 4: Oscilloscope Measurement

1. Connect probe to Timing 1 SMA port
2. Trigger: Normal, rising‑edge, threshold 1.6 V
3. Time base: Adjust for frame rate (e.g. 120 fps → 2 ms/div)
4. Expected result: Period = frame period, Pulse width = 1000 µs, Amplitude = 3.3 V

7 Summary

CounterAndTimerControl is powerful but requires careful configuration. It enables the camera to generate accurate timing signals for synchronizing external hardware. Proper signal routing and trigger setup are mandatory. Well‑suited for industrial inspection and scientific imaging setups with multi‑device coordination.