Image processing device, endoscope system, image processing method, and computer-readable storage device

An endoscope system comprising:

• an imaging section that captures a captured image;
• an evaluation value calculation section that calculates an evaluation value that is used to determine whether or not an inter-frame state of an object within the captured image is a stationary state;
• an estimated noise amount acquisition section that acquires an estimated noise amount of the captured image;
• a determination section that determines whether or not the inter-frame state of the object is the stationary state based on the evaluation value, the estimated noise amount, and a specific condition;
• and
• a noise reduction processing section that performs a first noise reduction process that is a time-direction noise reduction process on the captured image when it has been determined that the inter-frame state of the object is the stationary state, and performs a second noise reduction process that includes at least a spatial-direction noise reduction process on the captured image when it has been determined that the inter-frame state of the object is not the stationary state,
• the specific condition being an observation state of the object, or whether a target area of a noise reduction process belongs to a front-field-of-view area or a side-field-of-view area, or a type of the captured image.

An image processing method comprising:

• calculating an evaluation value that is used to determine whether or not an inter-frame state of an object within a captured image is a stationary state;
• acquiring an estimated noise amount of the captured image;
• determining whether or not the inter-frame state of the object is the stationary state based on the evaluation value, the estimated noise amount, and a specific condition, the specific condition being an observation state of the object, or whether a target area of a noise reduction process belongs to a front-field-of-view area or a side-field-of-view area, or a type of the captured image;
• and
• performing a first noise reduction process that is a time-direction noise reduction process on the captured image when it has been determined that the inter-frame state of the object is the stationary state, and performing a second noise reduction process that includes at least a spatial-direction noise reduction process on the captured image when it has been determined that the inter-frame state of the object is not the stationary state.

A computer-readable storage device with an executable program stored thereon, wherein the program instructs a computer to perform steps of:

• calculating an evaluation value that is used to determine whether or not an inter-frame state of an object within a captured image is a stationary state;
• acquiring an estimated noise amount of the captured image;
• determining whether or not the inter-frame state of the object is the stationary state based on the evaluation value and the estimated noise amount;
• and
• performing a first noise reduction process that is a time-direction noise reduction process on the captured image when it has been determined that the inter-frame state of the object is the stationary state, and performing a second noise reduction process that includes at least a spatial-direction noise reduction process on the captured image when it has been determined that the inter-frame state of the object is not the stationary state.