opencv image proccessing not recognized text(OCR)

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my code is to detect an document using android mobile camera (realtime).this is under oncameraframe().also i am using custom camera which is extend the Javacameraview.images taking from this is low in qualiy. and samml size(35kb).also this will not do the OCR processing.is there a way to capture high quality image?

    Mat mHsvMat = new Mat(src.rows(), src.cols(), CvType.CV_8UC1, new Scalar(0));
    Imgproc.cvtColor(src, mHsvMat, Imgproc.COLOR_BGRA2GRAY, 4);

    Imgproc.GaussianBlur(src, src, new Size(5, 5), 0);

    Imgproc.Canny(mHsvMat, mHsvMat, 75, 200);

Imgproc.adaptiveThreshold(mHsvMat, mHsvMat, thresholdLevel, Imgproc.ADAPTIVE_THRESH_MEAN_C, Imgproc.THRESH_BINARY,3 , 0);