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Simple Capture Configuration

This configuration defines a camera, configures the camera, and then captures some images. It's the minimum needed to do something useful.

Camera Definition

This block creates the camera with the specified parameters. It shows the use of the __target__ tag to specify a python class to instantiate.

The configuration is jinja2, which is expanded to yaml and then imported into the application as a dict. The jinja2 defaults can be overridded by passing a key=value argument tock-run. For example:

ck-run configs/simple-capture.yaml camera_mode=0

The variable camera can be referenced later in the configuration file with the __instance__ tag.

Configuration Equivalent Python Code 
camera:
  __target__: picamkit.camera.Camera
  camera_id: {{ camera_id | default(0) }}
  mode: {{ camera_mode | default(1) }}
  vflip: false
  hflip: false
  preview: false
    
camera = picamkit.camera.Camera(
  camera_id=0,
  mode=1,
  vflip=False,
  hflip=False,
  preview=False
)

Configure the Camera

This block simply calls several functions that perform specific configurations on the camera itself.

It finishes by saving all the camera configuration settings to files in the output directory so you have a record of all the settings the images were captured with. The variable output_dir is automatically set by the ck-run application, defaulting to local/<timestamp>.

This can be overridded in either of two ways. In the first example, the ouput directory will be ../capture/<timestamp>:

$ ./ck-run -o ../capture configs/simple-capture.yaml

In this example, the ouput directory will be ../capture:

$ ./ck-run configs/simple-capture.yaml output_dir=../capture
Configuration Equivalent Python Code 
configure_cam:
  - __target__: picamkit.camera.set_whitebalance
    camera:
      __instance__: camera
    mode:
      __enum__: picamkit.camera.AwbModeEnum.AUTO
  - __target__: picamkit.camera.set_exposure
    camera:
      __instance__: camera
    metering_mode:
      __enum__: picamkit.camera.MeteringModeEnum.SPOT
    wait: true
  - __target__: picamkit.camera.set_focus
    camera:
      __instance__: camera
    mode:
      __enum__: picamkit.camera.AfModeEnum.AUTO
    not_available_ok: true
    wait: true
  - __target__: picamkit.utils.save_camera_configs
    camera:
      __instance__: camera
    outdir: {{ output_dir }}
    
configure_cam = [
  picamkit.camera.set_whitebalance(
    camera=camera,
    mode=picamkit.camera.AwbModeEnum.AUTO
  ),
  picamkit.camera.set_exposure(
    camera=camera,
    metering_mode=picamkit.camera.MeteringModeEnum.SPOT,
    wait=True
  ),
  picamkit.camera.set_focus(
    camera=camera,
    mode=picamkit.camera.AfModeEnum.AUTO,
    not_available_ok=True,
    wait=True
  ),
  picamkit.utils.save_camera_configs(
    camera=camera,
    outdir='local/1715125743'
  )
]

Capture Pipeline

This final section builds the capture pipeline. This is a number of generators that are linked to each other in the order specified in the configuration.

Configuration Equivalent Python Code 
pipeline:
  - __target__: picamkit.ops.control.simple
    max_frames: {{ max_frames | default(10) }}
  - __target__: picamkit.ops.camera.capture
    camera:
      __instance__: camera
    arrays:
      - main
    immediate: true
  - __target__: picamkit.ops.imaging.resize
    width: 1280
    height: 720
    preserve_aspect: true
  - __target__: picamkit.ops.sink.save_item
    outdir: {{ output_dir }}
  - __target__: picamkit.ops.sink.save_rgb
    outdir: {{ output_dir }}
    
pipeline = picamkit.ops.control.simple(
  max_frames=10
)
pipeline = picamkit.ops.camera.capture(
  pipe=pipeline, 
  camera=camera, 
  arrays=['main], 
  immediate=True
)
pipeline = picamkit.ops.imaging.resize(
  pipe=pipeline,
  width=1280,
  height=720,
  preserve_aspect=True
)
pipeline = picamkit.ops.sink.save_item(
  pipe=pipeline,
  outdir='local/1715125743'
)
pipeline = picamkit.ops.sink.save_rgb(
  pipe=pipeline,
  outdir='local/1715125743'
)

Running the Pipeline

Once the pipeline is built, ck-run runs the pipeline with code as simple as this:

for item in pipeline:
  pass

The output from running this configuration looks like this:

$ ./ck-run configs/simple-capture.yaml 
Loading config
Building config
Setting white balance
Setting exposure
Building picamkit.ops.control.simple
- max_frames: 10
Building picamkit.ops.camera.capture
- arrays: ['main']
- immediate: True
Building picamkit.ops.imaging.resize
- image_key: main.image
- width: 1280
- height: 720
- preserve_aspect: True
Building picamkit.ops.sink.save_item
- outdir: local/1715125743
- prefix: img
- mdata_key: metadata
Building picamkit.ops.sink.save_rgb
- outdir: local/1715125743
- file_format: png
- image_key: main.image
- format_key: main.format
- prefix: img
Running
Saving local/1715125743/img-0000.json
Saving local/1715125743/img-0000-rgb.png
Saving local/1715125743/img-0001.json
Saving local/1715125743/img-0001-rgb.png
Saving local/1715125743/img-0002.json
Saving local/1715125743/img-0002-rgb.png
Saving local/1715125743/img-0003.json
Saving local/1715125743/img-0003-rgb.png
Saving local/1715125743/img-0004.json
Saving local/1715125743/img-0004-rgb.png
Saving local/1715125743/img-0005.json
Saving local/1715125743/img-0005-rgb.png
Saving local/1715125743/img-0006.json
Saving local/1715125743/img-0006-rgb.png
Saving local/1715125743/img-0007.json
Saving local/1715125743/img-0007-rgb.png
Saving local/1715125743/img-0008.json
Saving local/1715125743/img-0008-rgb.png
Saving local/1715125743/img-0009.json
Saving local/1715125743/img-0009-rgb.png

The json files that are saved contain all the metadata from the image capture. These are saved by the operator picamkit.ops.sink.save_item included in the pipeline. An example is like this:

{
  "idx": 0,
  "main": {
    "format": "RGB888",
    "framesize": 8957952,
    "size": [
      2304,
      1296
    ],
    "stride": 6912
  },
  "metadata": {
    "AeLocked": true,
    "AfPauseState": 0,
    "AfState": 0,
    "AnalogueGain": 3.029585838317871,
    "ColourCorrectionMatrix": [
      1.5383427143096924,
      -0.3521742522716522,
      -0.18616284430027008,
      -0.3317224383354187,
      1.6765234470367432,
      -0.3447909653186798,
      0.0037013564724475145,
      -0.5590126514434814,
      1.5553213357925415
    ],
    "ColourGains": [
      1.7750877141952515,
      2.0837767124176025
    ],
    "ColourTemperature": 4058,
    "DigitalGain": 1.0024760961532593,
    "ExposureTime": 59989,
    "FocusFoM": 878,
    "FrameDuration": 199995,
    "LensPosition": 1.0,
    "Lux": 179.4264373779297,
    "ScalerCrop": [
      0,
      0,
      4608,
      2592
    ],
    "SensorBlackLevels": [
      4096,
      4096,
      4096,
      4096
    ],
    "SensorTemperature": 26.0,
    "SensorTimestamp": 83126207467000
  },
  "stamp": 83126151379817
}