PURPOSE: To provide an image processor which can satisfactorily binarize the analog images and also form the computer holograms.

CONSTITUTION: An analog image inputted from an input means 1 is supplied to a sampling means 2 and the value of every pixel is extracted. A neural network circuit 3 includes plural neurons and the synapses which connect these neurons to each other, and a function equivalent to the frequency characteristic of human eyes, for example, is set in a function setting means 4. The function set to the means 4 and the value of every pixel sampled by the means 2 are supplied to a calculation means 5 which calculates the threshold of every neuron. At the same time, the function set in the means 4 is supplied to a calculation means 6 which calculates the coupling coefficient of every synapse. Thus the circuit 3 performs the network operation processing to decide the neuron value. When this processing is converged, the value of every neuron is taken out and sent to an output means 7 as an output binarized image.