Ultrasound observation device, operation method of image signal processing apparatus, image signal processing method, and computer-readable recording medium

An image signal processing method comprising:

• acquiring, after white light generated by a light source unit is emitted to a subject from a tip portion of an endoscope, an imaging signal including a base component and a detail component, the imaging signal that is generated by an imaging element provided on the endoscope by receiving light reflected from the subject;
• generating an input image signal including a base component and a detail component on the basis of the imaging signal;
• changing a mode to one of a first mode and a second mode for outputting the input image signal to different destinations;
• acquiring, by a dividing unit, the input image signal when the first mode is set, and dividing the input image signal into a base component signal and a detail component signal when a second mode different from the first mode is set;
• performing, by a first tone compressing unit, a tone compression process on the base component signal to generate a compressed base component signal;
• generating a synthetic image signal based on the detail component signal and the compressed base component signal;
• and
• acquiring, by a second tone compressing unit, the input image signal when the second mode is set, and performing a tone compression process such that tone of input image signal becomes approximately equal to tone of the compressed base component signal.

A non-transitory computer-readable recording medium with an executable program stored thereon, the program causing a computer to execute:

• acquiring, after white light generated by a light source unit is emitted to a subject from a tip portion of an endoscope, an imaging signal including a base component and a detail component, the imaging signal that is generated by an imaging element provided on the endoscope by receiving light reflected from the subject;
• generating an input image signal including a base component and a detail component on the basis of the imaging signal;
• changing a mode to one of a first mode and a second mode for outputting the input image signal to different destinations;
• acquiring, by a dividing unit, the input image signal when the first mode is set, and dividing the input image signal into a base component signal and a detail component signal when a second mode different from the first mode is set;
• performing, by a first tone compressing unit, a tone compression process on the base component signal to generate a compressed base component signal;
• generating a synthetic image signal based on the detail component signal and the compressed base component signal;
• and
• acquiring, by a second tone compressing unit, the input image signal when the second mode is set, and performing a tone compression process such that tone of input image signal becomes approximately equal to tone of the compressed base component signal.