sentences:  Later, more complex image processing was performed on the nearly 100,000 photos sent back by the spacecraft, so that the topographic map, color map and panoramic mosaic of the moon were obtained, which achieved extraordinary results and laid a solid foundation for human landing on the moon.The cost of processing was fairly high, however, with the computing equipment of that era.That changed in the 1970s, when digital image processing proliferated as cheaper computers and dedicated hardware became available.