Problem implementing ultrasonic interrupt (new ping library)

Projects Programming
4 
  uint16_t blockCount;
  blockCount = pixy.getBlocks();

Is this value likely to change on each pass through loop()?

An awful lot of stuff you are doing in loop() makes no sense there. The camera characteristics are not likely to change, are they?

Dump that sketch. Create one that does NOTHING but initialize the serial port, read the ping sensor, and print the value to the serial port.

Tell us EXACTLY what you see in the Serial Monitor.