// Compute a modified version of the PSNR that takes into account only errors
// that can be detected by the Human Visual System. Only one channel.
// Color model must be YUV444 or YUV420.
// return psnr * 1024 or INFINITE_PSNR (=0)
public int computePSNR_HVS_M(
int[] src, int[] dst, int x, int y, int w, int h, int channelIdx, ColorModelType type) {
if ((type != ColorModelType.YUV420)
&& (type != ColorModelType.YUV422)
&& (type != ColorModelType.YUV444))
throw new IllegalArgumentException("Invalid image type: must be YUV 420, 422 or 444");
if ((channelIdx != 0) && (channelIdx != 1) && (channelIdx != 2))
throw new IllegalArgumentException(
"Invalid channel index: must be 0 for Y, 1 for U or 2 for V");
if ((x < 0) || (y < 0))
throw new IllegalArgumentException("Illegal argument: x and y must be positive or null");
if ((w <= 0) || (h <= 0))
throw new IllegalArgumentException("Illegal argument: w and h must be positive");
if (src == dst) return 0;
final int mse = computeCSFDeltaAvg(src, dst, x, y, w, h, channelIdx);
if (mse <= 0) return Global.INFINITE_VALUE;
// Formula: double mse = (double) (sum) / size
// double psnr = 10 * Math.log10(255d*255d/mse);
// Calculate PSNR << 10 with 1024 * 10 * (log10(65025L) = 49286
return 49286 - Global.ten_log10(mse);
}
// return psnr * 1024 or INFINITE_PSNR (=0)
public int computePSNR(
int[] data1, int[] data2, int x, int y, int w, int h, ColorModelType type) {
final long lsum = this.computeDeltaSum(data1, data2, x, y, w, h, type);
// Rescale to avoid overflow
final int isum = (int) ((lsum + 50) / 100);
if (isum <= 0) return Global.INFINITE_VALUE;
// Formula: double mse = (double) (sum) / size
// double psnr = 10 * Math.log10(255d*255d/mse);
// or double psnr = 10 * (Math.log10(65025) + (Math.log10(size) - Math.log10(sum))
// Calculate PSNR << 10 with 1024 * 10 * (log10(65025L) = 49286
// 1024*10*log10(100) = 20480
final int iterations = ((w - x) >> this.downSampling) * ((h - y) >> this.downSampling);
return 49286 + (Global.ten_log10(iterations) - Global.ten_log10(isum)) - 20480;
}
