Image processing apparatus using recursive filters

A diagnostic X-ray apparatus comprising:

• fluoroscopy means for outputting a fluoroscopic image signal by picking up a fluoroscopic image obtained by radiating an X-ray to an object;
• first recursive filter means including a frame memory, for adding an output of said fluoroscopy means and an output of said frame memory with predetermined weights to write the result of addition into said frame memory;
• subtracter means for subtracting the output of said frame memory from the output of said fluoroscopy means for every pixel;
• means for generating a factor k in accordance with the difference obtained by said subtracter means, the factor k and the difference having an inverse proportional relationship if the difference has a positive value;
• and
• second recursive filter means for adding a value which is (1-k) times the output of said fluoroscopy means and a value which is k times the output of said first recursive filter means.

A diagnostic X-ray apparatus comprising:

• fluoroscopy means for outputting a fluoroscopic image signal by picking up a fluoroscopic image obtained by radiating an X-ray to an object;
• first recursive filter means including a frame memory, for adding an output of said fluoroscopy means and an output of said frame memory with predetermined weights to write the result of addition into said frame memory;
• second recursive filter means for adding a value which is (1-k) times the output of said fluoroscopy means and a value which is k times the output of said first recursive filter means, a factor k being a positive number between 0 and 1;
• subtracter means for subtracting the output of said second recursive filter means from the output of said fluoroscopy means for every pixel;
• and
• means for setting the factor k in accordance with the difference obtained by said subtracter means, the factor k and the difference having an inverse proportional relationship if the difference has a positive value.