Method of controlling image memory system for non-interlace/interlace conversion

A method of controlling an image memory system in which image data is written into a first image memory and a second image memory, and read out the contents of the first image memory and the second image memory so as to convert the image data, the method comprising the steps of:

• writing each line of the image data alternately into the first image memory and the second image memory a plurality of dots by dots;
• writing the image data of the plurality of dots simultaneously into both the first image memory and the second image memory, when the plurality of dots include dots on one line and dots on the adjacent line;
• invalidating the image data of the dots for the second image memory written in the first image memory when the image data is read out from the first image memory;
• and
• invalidating the image data of the dots for the first image memory written in the second image memory when the image data is read out from the second image memory.

An image memory system comprising:

• a first field memory for writing image data on odd lines in parallel a plurality of dots by dots;
• a second field memory for writing image data on even lines in parallel a plurality of dots by dots;
• memory control means for controlling writing/reading of the image data with respect to the first and the second field memories;
• and
• parallel-to-serial conversion means for converting parallel image data read out from the first and the second field memories by the memory control means, into serial image data,
• said memory control means having means for writing, when the plurality of dots to be written includes dots for one field memory and dots for another field memory, the image data of the plurality of dots is simultaneously written into both the first and the second field memories.