Abstract: An accurate determination of the tissue state of a diseased portion is performed by use of an image obtaining apparatus employing a charge multiplying type solid state image obtaining element. A target subject is irradiated with an illuminating light that contains an excitation light, and the reflected light, which includes a fluorescence image, reflected from the target subject thereupon is detected by a charge multiplying type CCD. At this time, the fluorescent light image is passed through a rotating filter, and is detected as a wide band fluorescent light image and a narrow band fluorescent light image by the charge multiplying type CCD, and obtained as a wide band fluorescence image data and a narrow band fluorescence image data by an image processing unit. A fluorescence diagnostic image is obtained of the wide band fluorescence image data and the narrow band fluorescence image data, and displayed on a monitor.

Abstract: An image obtaining method and apparatus for an endoscope, wherein the S/N ratio of an observation image formed from the image signal obtained by a solid state image obtaining element equipped with a charge multiplying shift resistor is improved. A signal charge representing a fluorescent image is obtained of the fluorescent image formed of the fluorescent light emitted from a target subject upon the irradiation thereof by an excitation light emitted from an illuminating means, by a charge multiplying shift resistor. A readout means reads out the signal charge and outputs an image signal based on the read out signal charge. In obtaining an observation image signal based on the read out image signal, a computing means subtracts the dark noise image signal component from the read out image signal to obtain the observation image signal.

Abstract: Operation processing is performed on a first fluorescence image and at least either one of a second fluorescence image and a reflected reference light image to form a tissue condition image, which represents a tissue condition of living body tissues and has been compensated for a distance to the living body tissues. According to at least one of the three images, a judgment is made as to whether each image area in the tissue condition image is an abnormal light affected area or a normal light detection area. The abnormal light affected area is displayed in a form different from the normal light detection area.

Abstract: A fluorescent endoscope apparatus that displays as an image the autofluorescent light emitted from a target subject upon the irradiation thereof with an excitation light, wherein the scope means is improved and the size of the apparatus is made compact. An image obtaining unit, an illumination unit, and an excitation/reference-light unit are mounted adjacently on a rack located at a position remote from a scope means. The image obtaining unit, the illumination unit, and the excitation/reference-light unit are connected to the scope means by an image fiber, an illuminating-light guide, and an excitation/reference-light guide, respectively, Further, by making the length of the image fiber and the excitation/reference-light light guide longer than that of the illuminating-light light guide, the range in which the scope means is can be moved is limited only by the illuminating-light light guide.

Abstract: A fluorescent-light image display apparatus for displaying on a monitor a fluorescent-light image emitted from a target area irradiated by a excitation light. A photo-detector inputs the output value of the excitation light into an irregularity controller, which determines whether or not the output of the excitation light is smaller than a set value. If the output of the excitation light is determined to be larger than the set value, an irregularity detection signal is output to the main controller. The main controller stops the flow of drive-current to and the emission of excitation light from the GaN semiconductor laser, and displays a message on the monitor that an irregularity has occurred in the output of the excitation light when the output of the excitation light is larger than a predetermined value, the emission of the excitation light is stopped and the patient is not irradiated by excitation light having an energy density above a predetermined value.

Abstract: According to a method of and apparatus for displaying as an autofluorescent-light image emitted from a target subject upon the irradiation thereof by a excitation light, even for cases in which a malfunction of the apparatus occurs that prevents an operator from obtaining a desired image, a standard-image is displayed so as to enable an operator to safely and expediently remove the insertion portion of the endoscope from the body of a patient, whereby the safety of the patient can be ensured. When an irregularity in the temperature of one of the light sources, the operation of one of the drive apparatus, or other cause of an operational irregularity occurring in of one of the light sources is detected by the semiconductor-laser temperature detecting means, the reference-light source temperature detecting means, or the emission-output detecting means, in response to a detection signal thereof, the standard-image display mode is switched to automatically.

Abstract: A fluorescent-light image obtaining apparatus for obtaining an autofluorescent-light image emitted from a target tissue irradiated by an excitation light, wherein the safety of the patient is ensured against injury from exposure to excessive excitation light when the distance between the output end of the excitation light projector and the target tissue is short. A contact detector detects that the end of the excitation light projector of the endoscope is in contact with the target tissue. Then, an excitation light output controller receives a signal indicating that the end of the excitation light projector is in contact with the target tissue. In response to this signal, the excitation light output controller stops the emission of the excitation light, or reduces the intensity of the emitted excitation light to a safe intensity for the patient even while the end of the excitation light projector and the target tissue are in contact.

Abstract: An endoscope includes an objective optical system which is inserted into a body and an image taking device which takes an image formed by the objective optical system and outputs an image signal representing the image. An image restoration processing is carried out on a part of the image signal corresponding to a predetermined range in the image taking range of the image taking device.

Abstract: An f.theta. lens includes first and second lens groups arranged in this order from the entrance pupil side. The first lens group consists of a first lens having a negative or positive refracting power. The second lens group consists of a second lens having a positive refracting power and a third lens having a negative refracting power with the second and third lenses being cemented together. The second lens group has a positive refracting power as a whole. The following formulae (1) to (4) are satisfied.12.ltoreq..nu..sub.d2 -.nu..sub.d3 (1)-0.035.ltoreq..SIGMA.(.phi..sub.i /.nu..sub.di).ltoreq.0.005 (2)0.7.ltoreq..phi..sub.23 .ltoreq.2.0 (3)0.03.ltoreq.d.sub.12 .ltoreq.0.20 (4)wherein .phi..sub.i represents the power of i-th lens as numbered from the entrance pupil side standardized on the basis of the power of the whole system, .phi..sub.23 represents the power of the second lens group standardized on the basis of the power of the whole system, .nu..sub.