Video laryngeal endoscope system including 2D scan video kymography and laryngeal stroboscopy

Abstract

A video laryngeal endoscope system having flat scan video kymography and laryngoscopic functions for analyzing a motion state of a larynx comprises: a laryngoscope for viewing vocal cords; a light source for illuminating the vocal cords; a video camera which has a beam splitter for separating an image viewed by means of the laryngoscope and the light source into two images to acquire a flat scan kymographic image and a stroboscopic image; a dual image capturing unit for converting two image signals transmitted from the video camera into a digital image signal; a storage unit for storing the digital image signal; a control unit for analyzing the digital image signal of the storage unit and simultaneously displaying analysis results of the flat scan kymographic image and the stroboscopic image; and a computer comprising analysis software for analyzing the image signal of the storage unit; and a monitor for displaying photographed images and analysis results.

Claims

1. A video laryngeal endoscope system having two-dimensional scanning video kymography (2D VKG) and laryngeal stroboscopy functions; the system comprising: a laryngoscope configured to observe vocal folds; a light source configured to illuminate the vocal folds; a video camera configured to have a beam splitter for separating an image observed through the laryngoscope and the light source to acquire a 2D VKG image and a stroboscopic image; a computer configured to convert signals including 20 VKG images and stroboscopic images transmitted from the video camera into digital image signals, store the digital image signals, analyze the stored digital image signals and simultaneously display analysis results of the 2D VKG image and the stroboscopic image on a monitor; and the monitor configured to simultaneously display the 2D VKG image and the stroboscopic image and display the analysis results comprising normalized indices of the observed vocal folds and glottis, wherein the normalized indices comprise a glottis opening ratio.

2. The video laryngeal endoscope system of claim 1, wherein the video camera comprises: a first camera module configured to have a rolling shutter and acquire 2D VKG image by scanning vocal-fold mucosae; and a second camera module configured to acquire the stroboscopic image.

3. The video laryngeal endoscope system of claim 2, wherein the first camera module and the second camera module have a shutter speed of 1/1000 second or faster.

4. The video laryngeal endo scope system of claim 2, wherein the second camera module acquires an optical signal provided by the image obtained by the laryngoscope and the light source as an analog image signal, converts the analog image signal into a digital image signal, and adjusts a shutter time and a sampling rate.

5. The video laryngeal endoscope system of claim 1, wherein the light source is a continuous xenon light source.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic diagram illustrating a principle of line scanning video kymography (VKG) according to a conventional art.

(2) FIG. 2 is an image screen photographed by a line scanning VKG system according to a conventional art.

(3) FIG. 3 is a schematic block diagram of a video laryngeal endoscope system having two-dimensional scanning VKG (2D VKG) and laryngeal stroboscopy functions according to an exemplary embodiment of the present invention.

(4) FIGS. 4 and 5 are schematic diagrams illustrating a principle of 2D VKG used in the present invention, FIG. 4 showing a principle of scanning an entirety of vocal folds, that is, 2D scanning, and FIG. 5 showing images of the entirety of the vocal folds obtained by 2D scanning.

(5) FIG. 6 is a flowchart illustrating a method of analyzing a laryngeal motion state by a video laryngeal endoscope system having 2D VKG and laryngeal stroboscopy functions according to an exemplary embodiment of the present invention.

(6) FIG. 7 is a laryngeal endoscope image screen of a normal person.

(7) FIGS. 8 to 10 are 2D VKG image screens acquired according to the present invention.

(8) FIG. 11 shows comparative images of line scanning kymography according to a conventional art and 2D VKG according to the present invention.

(9) FIG. 12 shows image screens photographed by a video laryngeal endoscope system having 2D VKG and laryngeal stroboscopy functions according to the present invention.

MODES OF THE INVENTION

(10) Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the following exemplary embodiments are provided for those of ordinary skill in the art to sufficiently appreciate the present invention, and various modifications can be made thereto. The scope of the present invention is not limited to the exemplary embodiments described below.

(11) FIG. 3 is a schematic block diagram of a video laryngeal endoscope system having two-dimensional scanning video kymography (2D VKG) and laryngeal stroboscopy functions according to an exemplary embodiment of the present invention. A video laryngeal endoscope system having the 2D VKG and laryngeal stroboscopy functions for analyzing a laryngeal motion state according to an exemplary embodiment of the present invention includes a laryngoscope 10, a light source 20, a video camera 30, a computer 40, and a monitor (not shown). Here, the video camera 30 includes a beam splitter 32, a first camera module 34, and a second camera module 36, and the computer 40 includes a dual image capturing unit 42, a storage unit 44, a control unit 46, and analysis software 48.

(12) In a configuration of FIG. 3, the laryngoscope 10, which is a tool for observing vocal folds, is connected to the video camera 30 and makes it possible to take an image of a larynx including vocal folds and a glottis. Both a rigid type of laryngoscope and a curved type of laryngoscope may be used as the laryngoscope 10.

(13) In an exemplary embodiment, the laryngoscope 10 may be integrally implemented with the video camera 30, which will be described below.

(14) The video camera 30 is a device for recording and storing images observed through the laryngoscope 10. More specifically, the video camera 30 has the beam splitter 32 to separate an image taken by the laryngoscope 10 into two images and extracts 2D VKG and stroboscopy images by causing the first camera module 34 and the second camera module 36 to project two separated images.

(15) The first camera module 34 extracts 2D VKG image rather than line scanning kymography image based on a conventional art. The first camera module 34 will be described in detail below with reference to FIGS. 4 and 5.

(16) The second camera module 36 acquires a stroboscopic image by processing and observing an image of the glottis of the larynx which makes periodic motions at a high rate. More specifically, the second camera module 36 acquires an optical signal provided by images obtained by the laryngoscope 10 and the light source 20 as an analog image signal, converts the analog image signal into a digital image signal, and adjusts a shutter time and a sampling rate. In other words, the second camera module 36 samples a periodic motion of a target object, which is repeated at a high rate, at an appropriately low rate so that one-period elements of the repeated motions can be completely extracted.

(17) For example, the second camera module 36 may be implemented as a charge-coupled device (CCD) camera, and a function of the second camera module 36 may be implemented through a digital signal process (DSP) in a full high-definition (HD) camera.

(18) In an exemplary embodiment, the second camera module 36 images a glottal motion according to the adjusted shutter time and sampling rate. More specifically, the second camera module 36 preferably has a short shutter time. When the shutter time is long, one image is acquired as continuous images rather than a still image and an observer cannot clearly observe a state in which a target object makes periodic motions.

(19) In an exemplary embodiment, the second camera module 36 may adjust the shutter time according to brightness of the light source 20 and adjust the sampling rate to show a high-speed motion of a laryngeal glottis which cannot be observed with the naked eye as images of a low-speed motion or a still image. In other words, it is possible to observe whether the larynx is accurately closed and opened. For example, when the glottis of the larynx is opened and closed 100 to 250 times per second for vocalization, the shutter time of the second camera module 36 may be adjusted to have a time interval corresponding to 0.35 periods or less (preferably 0.1 periods or less) as a result of analyzing the glottal motion of the larynx, and the sampling rate may be adjusted so that a glottal motion output to a monitor can be accurately observed. A process in which sequential still images are continuously output through the monitor may be repeated to show the imaged glottal motion.

(20) The second camera module 36 may clearly observe a target object by using the continuous light source 20 rather than an intermittent light source according to a conventional stroboscopic method and thus extracts a stroboscopic image which is superior in terms of performance.

(21) The computer 40, which is a general-use personal computer, includes the image capturing unit 42, the storage unit 44, the control unit 46, and the analysis software 48. The dual image capturing unit 42, which is in the form of an image capture board, serves to convert a video signal transmitted from the video camera 30 into a digital image signal which can be processed by the computer 40, and may employ a general-use image signal processing board which facilitates editing of various images. Generally, an auxiliary substrate type, which may be inserted into a mainboard extension bus of the computer 40 in a slot form, may be used.

(22) The control unit 46 of the computer 40 stores a digital image signal of, for example, 25 to 30 consecutive frames per second transmitted from the dual image capturing unit 42 in the storage unit 44 and then controls the analysis software 48 to analyze a laryngeal motion state. In other words, the control unit 46 analyzes the image signal moved to the storage unit 44 to visualize analysis results of 2D VKG images and stroboscopic images, that is, a vibration state of the vocal folds and a motion state of the glottis, on the monitor (not shown), and displays a quantified clinical index.

(23) FIGS. 4 and 5 are diagrams illustrating a principle of 2D VKG used in the present invention. As shown in FIG. 4, for 2D VKG, the first camera module 34 of the video camera 30 is placed in a still state, and vocal-fold mucosae are scanned through a gap of a moving slit so that the entirety of the vocal folds are scanned, that is, 2D scanning is performed. Specifically, as shown in FIG. 5, a thin slit shutter moves on a plane of vocal-fold images and film is exposed during the movement. Since images acquired through such a procedure sequentially show several image rows obtained by capturing an entire image of the larynx in different temporal steps as one entire image, dynamic images of the entire larynx are shown.

(24) To this end, the first camera module 34 of the video camera 30 operates in a highly sensitive high-resolution manner and has a rolling shutter. Preferably, the first camera module 34 may use a rolling shutter type complementary metal oxide semiconductor (CMOS) camera module, and a shutter speed may be set to a high speed of 1/1000 second or faster to increase a resolution of images. In this case, a screen may be very dark, and thus a high-sensitivity and high-luminance light source may be used as the light source 20. Preferably, a very bright xenon light source is used as the light source 20 which illuminates the vocal folds. In the present invention, the very bright continuous light source may be used as the light source 20 instead of an intermittent light source (a strobe light source) used in the conventional stroboscopic method.

(25) While normal people or patients having an abnormal vocal-fold function are caused to vocalize a specific sound (i or eh) in a comfortable state, the vocal folds are photographed using the laryngoscope 10, the light source 20, and a rolling shutter camera corresponding to the first camera module 34. In this way, videos having a predetermined number, for example, 25 to 30, of consecutive frames per second are recorded as images recorded in a predetermined format, for example, an AVI format, and the recorded videos are played and output.

(26) Next, a method of analyzing a laryngeal motion state according to an exemplary embodiment of the present invention in the above-described video laryngeal endoscope system having the 2D VKG and laryngeal stroboscopy functions will be described in detail with reference to the accompanying drawings.

(27) FIG. 6 is a flowchart illustrating a method of analyzing a laryngeal motion state by the video laryngeal endoscope system having the 2D VKG and laryngeal stroboscopy functions according to an exemplary embodiment of the present invention. Referring to FIG. 6, first, kymograph images obtained by photographing motions of vocal folds using the laryngoscope 10, the light source 20, and the video camera 30 and stroboscopic images obtained by photographing a motion of a glottis are stored in the storage unit 44 of the computer 40 through the dual image capturing unit 42 (step S210).

(28) To analyze a laryngeal motion state, for example, the entirety of the vocal folds are photographed without vocalization. Then, during vocalization of i or eh, motions of the entirety of vocal-fold vibration parts are photographed and converted into 2D scanning kymograms and a motion state of the glottis is observed to acquire stroboscopic images.

(29) Next, the control unit 46 of the computer 40 forms a predetermined number of frames as frame-specific still screens to display the still screens on the monitor, and configures and displays a menu screen so that a user can select a frame that he or she wants to observe with a mouse or a keyboard (step S220).

(30) Next, the analysis software 48 of the computer 40 analyzes the kymograph images and the stroboscopic images and normalizes and displays various indices of the vocal folds and the glottis, for example, an average vocal-fold width with respect to a longitudinal-axial length of the glottis, a glottis opening ratio, which is a ratio of a vocal-fold opening period to a total period, an asymmetry index, which is a difference in degree of opening between the both vocal folds, a basic frequency, a vibration strength, regularity of vibration, a mucosal wave, symmetricity of the vibration, an outer boundary shape, an inner boundary shape, an abnormal cycle, vibration absence of vocal-fold mucosae, and the like (step S230). Using these indices, it is possible to evaluate a state more objectively and accurately.

(31) A 2D VKG image acquired by the video laryngeal endoscope system having the 2D VKG and laryngeal stroboscopy functions according to the present invention will be described below with reference to FIGS. 7 to 11 in comparison with the conventional art.

(32) FIG. 7 is a laryngoscope image screen of a normal person, and FIGS. 8 to 10 show 2D VKG image screens photographed by the video laryngeal endoscope system having the 2D VKG and laryngeal stroboscopy functions according to the present invention. FIGS. 8 to 10 are 2D VKG image screens of a normal adult male during vocalization, and 25 to 30 consecutive frames of video images stored in a digital format are moved to the storage unit 44 of the computer 40 by using the dual image capturing unit 42 and then displayed on the monitor (not shown).

(33) Specifically, FIG. 8 is a 2D VKG image screen of a normal man during low-voice vocalization, FIG. 9 is a 2D VKG image screen of a normal man during high-voice vocalization, and FIG. 10 is a 2D VKG image screen of a normal man during falsetto-voice vocalization.

(34) FIG. 11 shows comparative images of line scanning VKG (a) according to the conventional art and 2D VKG (b) according to the present invention.

(35) (a) of FIG. 11 is line scanning kymography for photographing a motion of a part of vocal folds. (a), which is an image according to the conventional art, has a disadvantage in that it is not an observation of the entirety of the vocal folds but an evaluation of a part of one line. In other words, when an examinee makes a vocalization once, only a kymogram for one line can be acquired, and since a motion of an entire region cannot be observed while the kymogram is acquired, there are problems in that there is no criterion to properly determine distortion caused by a motion of a patient and the like. (b) of FIG. 11 is a 2D VKG image obtained by photographing motions of the entirety of the vocal folds according to the present invention. According to the image of (b), motions of the entirety of the vocal folds may be observed in real time by overcoming the disadvantages of the image of (a), and thus it is possible to minimize distortion caused by a motion of the patient and the like.

(36) FIG. 12 shows image screens photographed by a video laryngeal endoscope system having the 2D VKG and laryngeal stroboscopy functions according to the present invention.

(37) Referring to FIG. 12, it is possible to simultaneously acquire a 2D VKG image and a stroboscopic image by using the video laryngeal endoscope system having the 2D VKG and laryngeal stroboscopy functions according to the present invention.

(38) Referring to (a) of FIG. 12, a concept of an image which may be acquired through the present invention is shown. The video laryngeal endoscope system having the 2D VKG and laryngeal stroboscopy functions according to the present invention is used to simultaneously acquire a 2D VKG image and a stroboscopic image, and the stroboscopic image and the 2D VKG image are respectively disposed on the left and right sides to be displayed as shown in (a) of FIG. 12 so that an observer can simultaneously view the two images. In an exemplary embodiment, the disposition of the 2D VKG image and the stroboscopic image may be changed by a setting of the observer.

(39) Referring to (b) of FIG. 12, as an example of images which may be acquired through the present invention, an image on the left side is a stroboscopic image and an image on the right side is a 2D VKG image. Since the two images can be simultaneously acquired and simultaneously displayed due to the present invention, a state of a larynx can be determined more objectively and accurately.

(40) In other words, conventionally, it is possible to take and acquire only a stroboscopic image or a 2D VKG image, whereas the present invention can use the light source 20 and the video camera 30 including the beam splitter 32, the first camera module 34, and the second camera module 36 to simultaneously acquire and display a stroboscopic image and a 2D VKG image.

(41) Although exemplary embodiments of a video laryngeal endoscope system having the 2D VKG and laryngeal stroboscopy functions according to the present invention have been described above, the present invention is not limited thereto. Rather, the present invention can be varied in various ways within the scope of the claims, the detailed description thereof, and the appended drawings, and the variations still fall within the present invention.