// Transform the json-type feature to mat-type public static Mat json2mat(String json) { JsonParser parser = new JsonParser(); JsonElement parseTree = parser.parse(json); // Verify the input is JSON type if (!parseTree.isJsonObject()) { System.out.println("The input is not a JSON type...\nExiting..."); System.exit(1); } JsonObject jobj = parser.parse(json).getAsJsonObject(); if (jobj == null || !jobj.isJsonObject() || jobj.isJsonNull()) { return null; } // Detect broken/null features JsonElement r = jobj.get("rows"); if (r == null) { return null; } int rows = jobj.get("rows").getAsInt(); int cols = jobj.get("cols").getAsInt(); int type = jobj.get("type").getAsInt(); String data = jobj.get("data").getAsString(); String[] pixs = data.split(","); Mat descriptor = new Mat(rows, cols, type); for (String pix : pixs) { String[] tmp = pix.split(" "); int r_pos = Integer.valueOf(tmp[0]); int c_pos = Integer.valueOf(tmp[1]); double rgb = Double.valueOf(tmp[2]); descriptor.put(r_pos, c_pos, rgb); } return descriptor; }