图像处理（需要图像的像素值）

Question

I want to make an app, in which I want to take a picture and input x,y axis it will show me corresponding point pixel value from the captured picture .

I don't have any knowledge about image processing well . So, how can I do it ? help me .

Answer 1

The way I have done this in the past is by writing the image to the filesystem and then decoding it. Admittedly its a little inefficient but it's functional.

This requires a number of steps. I suggest you read over this documentation . It describes the process of taking an image and saving it to the file system which you will need to do before you can do the rest of these steps.

Next you will need to use BitmapFactory to decode the image which will give you an instance of Bitmap which you can do all sorts of things with (documented here ). In this example I return the Color object for the pixel located at (50, 50) using getPixel() . This example assumes that the path the the image is mCurrentPhotoPath but should be wherever you saved the image.

private Color getColor() {
    // Get the dimensions of the View
    int targetW = mImageView.getWidth();
    int targetH = mImageView.getHeight();

    // Get the dimensions of the bitmap
    BitmapFactory.Options bmOptions = new BitmapFactory.Options();
    bmOptions.inJustDecodeBounds = true;
    BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
    int photoW = bmOptions.outWidth;
    int photoH = bmOptions.outHeight;

    // Determine how much to scale down the image
    int scaleFactor = Math.min(photoW/targetW, photoH/targetH);

    // Decode the image file into a Bitmap sized to fill the View
    bmOptions.inJustDecodeBounds = false;
    bmOptions.inSampleSize = scaleFactor;
    bmOptions.inPurgeable = true;
    Bitmap bitmap = BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
    return bitmap.getPixel(50, 50);
}

You can get RGB values from this Color object which is what I think you are wanting to do. That can be found under the Color object documentation on Android Developers as well.