https://github.com/techascent/tech.opencv
Opencv bindings via the tech.datatype library and javacpp
https://github.com/techascent/tech.opencv
Last synced: 7 months ago
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Opencv bindings via the tech.datatype library and javacpp
- Host: GitHub
- URL: https://github.com/techascent/tech.opencv
- Owner: techascent
- License: epl-1.0
- Created: 2018-10-02T17:07:05.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2020-06-15T16:33:52.000Z (about 6 years ago)
- Last Synced: 2024-07-13T04:46:57.251Z (almost 2 years ago)
- Language: Clojure
- Size: 393 KB
- Stars: 19
- Watchers: 5
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# tech.opencv
[](https://clojars.org/techascent/tech.opencv)
OpenCV bindings via javacpp.
You can read a bit more about it [here](http://techascent.com/blog/opencv-love.html).
## Usage
### Basic
Load/save, resize, clone. Becase opencv matrixes need to be released and thus aren't garbage collected they are bound to a think.resource.core/resource-context which unwinds in a way similar to C++ RAII or with-open.
Bindings to clojure.core.matrix and tech.datatype allow you to get into the properties of
a loaded matrix.
```clojure
(require '[tech.opencv :as opencv])
(require '[tech.v2.datatype :as dtype])
(require '[tech.v2.datatype.functional :as dfn])
(let [src-img (opencv/load "test/data/test.jpg")
dest-img (opencv/clone src-img)
num-elems (dtype/ecount src-img)
;;Save as jpg and spend an hour scratching head...
test-fname "darken.png"
convert-fn (fn [input]
(float (Math/floor (* 0.5 input))))]
;;darken img. Float data is range 0-255
(delete-test-file! test-fname)
(-> (unary-op/unary-reader :int16 (unchecked-short (quot x 2)) src-img)
(dtype/copy! dest-img)
(opencv/save test-fname))
(let [result (opencv/load test-fname)
result-data (float-array num-elems)]
(dtype/copy! result result-data)
(is (dfn/equals (take 10 result-data)
(map convert-fn (take 10 (dtype/->reader src-img)))))))
```
### Datatype Tensors
Integrated with the tech.v2.tensor math system:
```clojure
(require '[tech.v2.tensor :as dtt])
(let [test-image (opencv/load "test/data/test.jpg")
;;Select is in-place so this did not change the image at all.
bgr-image (dtt/select test-image :all :all [2 1 0])
;;Copy src dest
dest-image (dtype/copy! bgr-image (dtype/from-prototype test-image))]
;;The datatype library has the convention that the thing that is mutated
;;is returned from the function.
(opencv/save dest-image "bgr.jpg"))
```
A bit more involved example:
```clojure
(let [test-image (opencv/load "test/data/test.jpg")
result
(-> test-image
(dtt/select :all :all [2 1 0])
(dfn/+ 50)
;;Clamp top end to 0-255
(dfn/min 255)
(dtype/copy! (dtype/from-prototype test-image)))]
(opencv/save result "bgr-lighten.jpg"))
```
### Further Reference
Please refer to the [tests](test/tech/opencv_test.clj),
[tensor tests](test/tech/opencv_compute_test.clj),
and [opencv.clj](src/tech/opencv.clj).
## License
Copyright © 2019 [Tech Ascent, LLC](https://github.com/tech-ascent).
Distributed under the Eclipse Public License either version 1.0 or (at
your option) any later version.