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73 lines
2.1 KiB
Markdown
73 lines
2.1 KiB
Markdown
node-red-node-annotate-image
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==================
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A <a href="http://nodered.org" target="_new">Node-RED</a> node that can annotate
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a JPEG image.
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The node is currently limited to drawing rectangles and circles over the image.
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That can be used, for example, to annotate an image with bounding boxes of features
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detected in the image by a TensorFlow node.
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Install
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-------
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Run the following command in your Node-RED user directory - typically `~/.node-red`
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npm install node-red-node-annotate-image
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Usage
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-----
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The JPEG image should be passed to the node as a Buffer object under `msg.payload`.
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The annotations are provided in <code>msg.annotations</code> and are applied in order.
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Each annotation is an object with the following properties:
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- `type` (*string*) : the type of the annotation - `rect` or `circle`
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- `x`/`y` (*number*) : the top-left corner of a `rect` annotation, or the center of a `circle` annotation.
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- `w`/`h` (*number*) : the width and height of a `rect` annotation
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- `r` (*number*) : the radius of a `circle` annotation
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- `bbox` (*array*) : this can be used instead of `x`, `y`, `w`, `h` and `r`.
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It should be an array of four values giving the bounding box of the annotation:
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`[x, y, w, h]`. If this property is set and `type` is not set, it will default to `rect`.
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- `label` (*string*) : an optional piece of text to label the annotation with
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- `stroke` (*string*) : the line color of the annotation. Default: `#ffC000`
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- `lineWidth` (*number*) : the stroke width used to draw the annotation. Default: `5`
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- `fontSize` (*number*) : the font size to use for the label. Default: `24`
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- `fontColor` (*string*) : the color of the font to use for the label. Default: `#ffC000`
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Examples
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--------
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```javascript
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msg.annotations = [ {
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type: "rect",
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x: 10, y: 10, w: 50, h: 50,
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label: "hello"
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}]
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```
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```javascript
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msg.annotations = [
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{
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type: "circle",
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x: 50, y: 50, r: 20,
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lineWidth: 10
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},
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{
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type: "rect",
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x: 30, y: 30, w: 40, h: 40,
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stroke: "blue"
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}
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]
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```
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```javascript
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msg.annotations = [ {
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type: "rect",
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bbox: [ 10, 10, 50, 50]
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}]
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```
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