The fundamental studies for a steady-state x-ray generator having a cold cathode radiation tube are described. This generator having a diode was constructed in order to generate stable x-ray intensities and consisted of the following components: a DC power supply with a maximum output voltage of +100kV, an oil diffusion pump, and an x-ray tube. The x-ray tube for fundamental studies was of the diode type which was connected to a vacuum pump with a constant pressure of 1.3×10-3 Pa and consisted of the following major devices: a long anode tip made of tungsten, a ring cathode made of brass, a ceramic insulator, and an acrylic resin window. The electrons emitted from the cathode by a strong electric field were accelerated to the tip of anode elec. The tube current was regulated by a resistor of 500kΩ and the anode-cathode space. The tube voltage was less than 70kV, and the current was less than 3. OrnA due to the current capacity of the power supply. The x-ray intensity rate was a. ut 8μC/kg. s at 1.0m from the source with a tube voltage of 59kV and a current of 1.0 mA. The x-ray quality became hard according to increases in the to voltage. The effective focal spot size was primarily determined by the diameter of the anode tip and its value was less than 4.0mm.

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The fundamental studies for the single flash x-ray generat r utilizing a compact diode for soft radiography are described. This generator consisted of the following essential components: a highvoltage power supply, a ready-made pulse condenser of 95nF-100kV, a single high-voltage impulse switching system, a turbo molecular pump, and a flash x-ray tube with a coaxial cable of 20D (5.0m). The flash x-ray tube was of the compact diode type which was connected to the turbo molecular pump with a constant pressure of 1.1×10-3 Pa and consisted of the following major devices: a long anode tip made of tungsten, a ring-shaped cathode made of graphite, a vacuum vessel made of stainless steel, an internal output mouth of x-rays, a polyoxymethylene insulator, diaghragms, and an x-ray window made of polyethylene terephthalate. Tihis generator employed a simple transmission line, and the condenser in the pulser was charged from 50 to 80kV by the power supply, and the electric charges in the condenser were discharged to the x-ray tube through a coaxial cable by the impulse switching system. The peak tube voltage increased according to increases in the condenser charged voltage and to increases in the anoe-cathode plane (A-Cp) space. The peak tube current primarily increased when the charged voltage was increased, and its value was less than 7kA. The pulse width of the flash xrays ranged from 100 to 200ns, and the time integrated x-ray intensity with a charged voltage of 77kV and an A-Cp space of 1.5mm was about 1μC/kg at 1.0m from the source. The effective focal spot size was primarily determined by the diameter of the anode tip, and its value was 3.0mm when an anode diameter of 3.0mm was employed.

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The research into the restoration procedures from a blurred image which is observed under a noisy environment to an original one are noted in various fields. Therefore many researchers have proposed various restoration schemes and have been carrying on research in order to contribute to further developments.
In this paper we propose a modified version to the projection filter which has been recently published. Namely, by considering the correlation between the brightness of neighbouring pixcels, we modified the optimization process without constraint to the optimizing process with constraint depending on correlation values. Simulation studies were carried out for various correlation values to show both the feasibility and this accuracy of our approach.

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