---
title: "How To: Find a Part from a Camera Image"
product: "LumiScan Object Finder"
component: "lumiscan-object-finder"
version: "1.1.0"
display_version: "1.1.0.7"
latest_version: true
language: "en"
url: "https://docs.hdvisionsystems.com/en/lumiscan-object-finder/1.1.0/how-tos/find-a-part-from-a-camera-image.html"
---

# How To: Find a Part from a Camera Image – LumiScan Object Finder

Start to finish: teach a part from a live camera, find it, and make the settings survive a restart.

## Before you start

- LumiScan Cam Driver is installed on the same device and publishing an image, for example at `hdvisionsystems/lumiscan-cam-driver/camera1/output/image`.
- LumiScan Object Finder is installed - on ctrlX OS also licensed - and `system/modules` lists `module-1`.
- The part is in front of the camera, in the lighting the installation will actually use.

## Step 1: teach the first view

Look at the live image and note the pixel rectangle the part occupies - on ctrlX OS the ctrlX web interface shows the image - or read `width` and `height` from the image node.

Set the inputs and execute:

```
system/create-object/input/input-image-address = hdvisionsystems/lumiscan-cam-driver/camera1/output/image
system/create-object/input/object-id           = screw-m6
system/create-object/input/crop/startX         = 820
system/create-object/input/crop/startY         = 400
system/create-object/input/crop/width          = 160
system/create-object/input/crop/height         = 120
write system/create-object/execute
```

Check `system/create-object/output/status-code` is `1`, and `output/object-path` names the file. `system/objects` should now include `screw-m6`.

Crop tightly. Background inside the template is background the detector will expect to see.

## Step 2: teach the other orientations

The detector does not rotate a picture, so each orientation the part arrives in needs its own **object**. Repeat step 1 with a different `object-id` - `screw-m6-tilted`, say - and search for it in its own run.

If the part only ever arrives one way up, one object is enough.

## Step 3: find it

```
module-1/find-object/input/input-image-address = hdvisionsystems/lumiscan-cam-driver/camera1/output/image
module-1/find-object/input/object-id           = screw-m6
module-1/find-object/input/nms-min-dist        = 40
write module-1/find-object/execute
```

Read `module-1/find-object/output/status-code`. `1` means the run completed; then read `output/result`.

`nms-min-dist` at roughly half the part’s size in pixels stops one part being reported as a cluster of matches.

## Step 4: set the threshold from real parts

Run step 3 several times with real parts and note the `score` of the genuine matches. Then set

```
module-1/find-object/input/confidence-threshold = <a little below the worst genuine score>
```

If genuine scores hover near the threshold, turn on blurring - set `module-1/find-object/input/preprocess/blur-sigma-x` to `1.0` - and measure again. See [Tuning the Search](https://docs.hdvisionsystems.com/en/lumiscan-object-finder/1.1.0/lumiscan-object-finder/tuning-the-search.html).

## Step 5: make it permanent

Settings take effect immediately but are not saved until you ask:

```
system/save-module-inputs/input/module-id = module-1
write system/save-module-inputs/execute
write system/save-current-modules/execute
```

Both should report status `1`. The module and its settings now come back after a restart.

## Step 6: run it from a control program

Per cycle:

1. Write to `module-1/find-object/execute`.
2. Read `module-1/find-object/output/status-code`.
3. If it is negative, the run failed - read `output/status-text` for the reason and do not use the result.
4. If it is `1`, read `output/result`. An empty `matches` list means the part was not there.

Read the outputs **before** triggering the next `execute`: a run empties them as it starts.

To have every frame of the camera searched without a call per image, see [Finding Objects on an Image Stream (Experimental)](https://docs.hdvisionsystems.com/en/lumiscan-object-finder/1.1.0/lumiscan-object-finder/processing-an-image-stream.html).

## If the part is not found

Problems are described step by step in [Troubleshooting](https://docs.hdvisionsystems.com/en/lumiscan-object-finder/1.1.0/troubleshooting.html):

- [The result is empty although the status code is `1`](https://docs.hdvisionsystems.com/en/lumiscan-object-finder/1.1.0/troubleshooting.html#faq-empty-result) - scores just below the threshold, a part found in some orientations or at some working distances only, or never found at all
- [One part is reported several times](https://docs.hdvisionsystems.com/en/lumiscan-object-finder/1.1.0/troubleshooting.html#faq-duplicate-matches)
- [Status codes and error messages](https://docs.hdvisionsystems.com/en/lumiscan-object-finder/1.1.0/troubleshooting.html#ts-status-codes) - when `status-code` is negative