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This article shows you the example analysis of changing pictures to grayscale in OpenCV Android, which is concise and easy to understand, which can definitely brighten your eyes. I hope you can get something through the detailed introduction of this article.

First, copy a picture logo.jpeg under the drawable of res.

Then add a button and a picture to the activity_main.xml interface

Return to the code file

First initialize the OpenCV

OpenCVLoader.initDebug ()

Then load the button and write the button event

Public void onClick (View view) {

BitmapFactory.Options options = new BitmapFactory.Options ()

/ / set the image read to argb8-bit

Options.inPreferredConfig = Bitmap.Config.ARGB_8888

/ / read the original resource picture

Bitmap bmp = BitmapFactory.decodeResource (getResources (), R.drawable.logo, options)

/ / create a Mat object scr as the source image resource dst as the target image resource

Mat src = new Mat ()

Mat dst = new Mat ()

/ / convert the loaded bmp image to the Mat object of scr

Utils.bitmapToMat (bmp, src)

/ / the Mat object of src is changed to grayscale and copied into the Mat object of dst

Imgproc.cvtColor (src, dst, Imgproc.COLOR_BayerGB2GRAY)

/ / then convert the Mat object of dst back into the bmp image

Utils.matToBitmap (dst, bmp)

/ / reassign a value to the picture

ImageView img = findViewById (R.id.img1)

Img.setImageBitmap (bmp)

}

Then we run directly in the virtual machine.

According to what I did in DEMO, I directly reported an error when I went to Imgproc.cvtColor. I haven't found any reason yet. It should be that the parameter of the new version in opencv is different, because I don't know about caching yet. Later, if you finish learning here, learn about the source code of C++ and analyze it, and then come back to deal with it here.

Later, I removed the 3.3.1 version, under the 2.4 version, so the packaged APK is no longer 80m, become 30m, much smaller, and so familiar with the opencv, and then their own useful packaging, reducing the size of the APK.

The above is the example analysis of changing pictures to grayscale in OpenCV Android. Have you learned any knowledge or skills? If you want to learn more skills or enrich your knowledge reserve, you are welcome to follow the industry information channel.

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