> For the complete documentation index, see [llms.txt](https://stage-precision.gitbook.io/grid/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://stage-precision.gitbook.io/grid/camera-calibration/using-the-calibration-object/capture-window-breakdown.md). # Capture Window Breakdown The **Capture Window** is used to collect calibration data, inspect marker detection, monitor map values, and evaluate the current solve status. The available panels and views depend on the selected calibration workflow. Some workflows show lens information, some show tracking information, and others only show the image and capture status. {% hint style="info" %} The calibration process may start as soon as the Capture Window is opened if **Auto Calibrate** is enabled. {% endhint %}

*** ## Top Bar The top bar of the Capture Window contains the main capture controls and process status readouts. #### Auto Calibrate The **Auto Calibrate** toggle enables or disables automatic acquisition of new calibration captures.

When Auto Calibrate is enabled, Grid Studio continuously collects suitable calibration data and refines the calibration. Disable Auto Calibrate when you want to pause the process and inspect the current result. {% hint style="info" %} If you want to pause and evaluate the calibration, turn **Auto Calibrate** off and wait until **Capture**, **Analyse**, and **Solve** all show **Idle**. {% endhint %} #### Number of Captures The **Num Captures** readout shows how many captures were taken in the current Capture Window session.

If the Capture Window is closed and opened again, this number may reset to zero. This means it can be different from the number of captures shown in the Solve Status. #### Process Status The top right of the Capture Window shows the current status of the calibration process.

Typical status readouts include: * **Capture** * **Analyse** * **Solve** These indicate which part of the calibration process is currently busy or idle. When Auto Calibrate is enabled, Grid Studio can continue capturing, analysing, and solving automatically. *** ## Image Capture Controller The **Image Capture Controller** shows the camera image and different analysis views used during calibration. It helps you check whether the camera image is correct, whether Calibration Pattern markers are detected, and how the current solve aligns the virtual setup with the real image. {% hint style="info" %} You can double-click the Image Capture Controller to expand it for a larger view. {% endhint %} #### Media Input View The **Media Input** view shows the clean camera image from the selected Media Input. Use this view to check that: * the correct camera source is selected * the image is visible * the image is sharp enough * the Calibration Pattern is readable * the image is not cropped, scaled, or processed unexpectedly

#### April Analyze Engine The **April Analyze Engine** view shows which Calibration Pattern markers are detected by the system. Detected markers are visualized with colored overlays. Partial, incomplete, or invalid marker detections are ignored. Use this view to check whether the Calibration Pattern is detected reliably across the image.

{% hint style="info" %} If only a small part of the Calibration Pattern is detected, check focus, exposure, marker size, viewing angle, and whether the Calibration Image is displayed correctly. {% endhint %} #### Solve Engine Camera View The **Solve Engine Camera View** shows how the virtual calibration geometry aligns with the real camera image. This view is useful for checking whether the current calibration result is improving and whether the virtual Calibration Screens line up with the real Calibration Pattern.

{% hint style="info" %} For easier visual comparison, it can help to invert or adjust the color of the Calibration Screens after exporting the Calibration Images. {% endhint %} #### Close Expanded View When a view is expanded, use the **Close Viewer** button in the top right corner to return to the normal Capture Window layout.

*** ## Map Capture Controller The **Map Capture Controller** shows the current values received from the maps used by the calibration workflow. This can include tracking, rotation, lens encoder, or other mapped values.

#### Lens Encoder Readouts If the workflow uses lens encoder data, the Map Capture Controller can show values such as: * **Zoom** * **Focus** These values are usually received as Custom Data from the selected Input Map. #### Tracking State The tracking state indicates whether the mapped tracking data is currently active. Use this to check whether the selected map is providing live data. If the tracking state is inactive or not updating, check the map setup on the Camera Object or source object. #### Position and Rotation For tracked camera workflows, the Map Capture Controller can show position and rotation values. These values help confirm that the calibration workflow is receiving the expected camera movement data. Use this area to check that: * position values update when the camera moves * rotation values update when the camera rotates * zoom and focus values update when the lens changes * the correct map is selected in the Calibration Object {% hint style="warning" %} If the values in the Map Capture Controller do not update, the Calibration Object may be referencing the wrong Input Map or the map may not be configured correctly. {% endhint %} *** ## Solve Status The **Solve Status** area shows the current quality and coverage of the calibration. It helps you decide whether enough useful data has been collected or whether additional captures are needed.

#### Number of Captures The solve status can show how many captures are currently used by the calibration solve. This can differ from the top bar **Num Captures** value, because the top bar readout is based on the current Capture Window session. #### Reprojection Error The reprojection error describes how well the solved calibration matches the detected image points. Lower reprojection error usually indicates a better match. However, reprojection error should not be evaluated alone. Good coverage across the sensor, screen area, lens range, and movement volume is also important. #### Sensor Coverage Sensor coverage shows how much of the camera sensor area has been covered by useful calibration data. Try to collect captures that cover as much of the image sensor as possible. This usually improves the calibration, especially for lens distortion and wide-angle behavior. #### Screen Coverage Screen coverage shows how much of the Calibration Screens has been observed during the calibration. If some screens or screen areas are not covered well enough, capture more data where those areas are visible. #### Repositioned Screens For workflows that can reposition Calibration Screens, the solve status can show whether the connected screens have been sufficiently observed and repositioned. Red screens or red screen areas indicate that more captures are needed. {% hint style="info" %} Red areas usually indicate missing or insufficient data. Capture more images from positions where those areas are visible. {% endhint %} #### Rejected Points Some detected points may be rejected by the solver. Rejected points are usually ignored because they do not fit the current solve well enough. This can happen because of incorrect detections, motion blur, bad focus, partial markers, reflections, or inaccurate reference data. *** ## Zoom Focus Steps The **Zoom Focus Steps** view shows which zoom and focus positions have been captured and how the calibration behaves at those lens positions. This view is mainly relevant for workflows that use zoom and focus encoder data.

#### Zoom / Focus Map The view shows calibration coverage across the zoom and focus range. Captured lens positions are shown as points in the graph. This helps you see which parts of the lens range are already covered and which areas may still need more calibration data. #### Inspecting a Step You can expand the Zoom Focus Steps view by double-clicking it. After expanding the view, click a point in the graph to inspect the calibration information for that zoom/focus position. The readout can include information such as: * zoom value * focus value * number of captures * reprojection error * sensor coverage * screen angle or related quality information #### Sensor Coverage per Step Try to capture useful sensor coverage at each important zoom/focus position. A lens position with low sensor coverage may need additional captures from different camera angles, distances, or screen positions. {% hint style="info" %} For lens calibration, try to cover as much of the sensor as possible across the relevant zoom and focus range. {% endhint %} *** ## How to Use the Capture Window Feedback The Capture Window is not only used to collect data. It also helps you decide what data is still missing. #### Check Detection First Before collecting many captures, check that the Calibration Pattern is detected reliably. Use the Media Input view and April Analyze Engine view to verify that markers are visible and detected. #### Watch the Map Values Use the Map Capture Controller to confirm that tracking, rotation, zoom, focus, or axis values are updating correctly. If the values are wrong or not updating, fix the map setup before continuing. #### Capture Missing Coverage Use the Solve Status and Zoom Focus Steps views to identify missing coverage. Capture additional data where: * sensor coverage is low * screen coverage is incomplete * reprojection error is high * zoom/focus areas are missing * red screen areas indicate insufficient observations #### Pause Before Evaluating When Auto Calibrate is enabled, the calibration may still be capturing, analysing, or solving. Turn Auto Calibrate off and wait until all process states are idle before evaluating the current result. *** ## Before Continuing Checklist Before collecting a large amount of calibration data, check the following: * The correct Media Input is visible in the Capture Window. * The Calibration Pattern is clearly visible. * The April Analyze Engine detects enough markers. * The Map Capture Controller shows the expected map values. * Tracking state is active if tracking is required. * Position and rotation update if required by the workflow. * Zoom and focus update if required by the workflow. * The Solve Engine Camera View roughly matches the real image. * Auto Calibrate is enabled only when you are ready to collect data. * Capture, Analyse, and Solve are idle before evaluating the result.