Patent Grant
7547277
This invention relates to endoscope systems, and, more particularly, to insuring that endoscope images accurately show anatomical features imaged with endoscope systems.
Endoscope systems have been in general use for many years for non-invasively viewing anatomical features such as tissues and organs inside the human body. Endoscope systems typically include an endoscope tip having a flexible or rigid insertion tube having a headpiece mounted at its proximal end and a viewing window at its distal end. The headpiece of an endoscope tip having a flexible insertion tube normally includes controls, such as wheels or levers, connected to the distal end of the insertion tube by control wires to steer the end of the insertion tube in different directions. By manipulating the controls, an endoscopist can direct the viewing window at the distal end of the insertion tube over a wide range of directions to view tissues and organs located adjacent the distal end of the endoscope tip. The insertion tube also normally includes an illumination device for directing light into the body in the vicinity of the distal end of the insertion tube. The illumination device is typically an optical fiber extending from a light source at the proximal end of the insertion tube to an illumination window at the distal end of the insertion tube. However, the illumination may also be a light source mounted at the distal end of the insertion tube and powered with electricity coupled through wires extending through the insertion tube. Endoscope tips also include a viewing device to allow the endoscopist to view anatomical features, such as tissues and organs, through the viewing window.
Endoscope systems may be used to simply view anatomical features, or they may be used to non-invasively conduct various diagnostic or surgical procedures within the body. Endoscope tips used for this purpose often include a biopsy channel extending through the insertion tube from an access port at the proximal end of the insertion tube to an opening at the distal end of the insertion tube. Biopsy and surgical instruments attached to the distal end of catheters may be fed through the biopsy channel of the endoscope tip and out the biopsy channel opening to position the instruments adjacent the viewing window of the endoscope tip. A biopsy or surgical procedure can then be performed by such techniques as manipulating the endoscope tip controls, advancing or retracting the endoscope tip within the body, advancing or retracting the catheter within the biopsy channel, or manipulating an actuator that is mechanically coupled to the biopsy or surgical instrument. Endoscope tips that do not have biopsy channels can also be used to perform biopsy or surgical procedures. In such cases, one or more biopsy or surgical instruments are introduced into the body by suitable means, such as by using a laparoscopic catheter. The biopsy or surgical instruments are then positioned within the field of view of the endoscope tip viewing window.
To improve performance, specialized endoscope tips have been developed to best accomplish their intended function. For example, upper endoscope tips are used for examination of the esophagus, stomach and duodenum, colonoscopes are used for examining the colon, angioscopes are used for examining blood vessels, bronchoscopes are used for examining the bronchi, laparoscopes are used for examining the peritoneal cavity, and arthroscopes are used for examining joint spaces. Instruments to examine the rectum and sigmoid colon, known as flexible sigmoidoscopes, have also been developed. The discussion of endoscope tips herein generally applies to these and other types of endoscope tips, and the term “endoscope tip” as used herein is meant to encompass all these and other such devices.
As mentioned above, endoscope tips include some form of viewing device for allowing anatomical features to be viewed through viewing windows. One type of viewing device uses a fiber-optic bundle extending from the viewing window at the distal end of the insertion tube to a viewing window on the headpiece. The fiber-optic bundle optically couples images throughout the length of the insertion tube. Another type of viewing device uses a miniature video camera positioned behind the viewing window at the distal end of the insertion tube. Wires extending from the video camera through the insertion tube couple power to the camera and video signals from the camera. Still another type of viewing devices uses a beam scanning device positioned behind the viewing window. Such scanned beam endoscope tips are a fairly recent innovation.
Regardless of which type of viewing device is used by an endoscope system, the image obtained by using the endoscope system may not accurately show the size, shape, color or other property of the anatomical features being viewed with the endoscope system. For example, it may be difficult to accurately asses the size of an internal object, such as a tumor, using any of the above-mentioned endoscope types. It may also be difficult to accurately show the true color of tissues or organs. For endoscope tips using optical fibers to view an image, the brightness of the image may be affected by light attenuation in the optical fiber. The color of the image obtained using an endoscope system may be affected, for example, by the spectral properties of the illuminating light or the spectral transfer properties of the optical fiber or video camera. Endoscope tips using cameras and beam scanners suffer from additional problems not encountered in endoscope tips using an fiber-optic bundle, such as the true contrast or sharpness of an endoscopically obtained image. And even endoscope tips using a fiber-optic bundle will suffer from these limitations if images obtained using the endoscope system are converted to digital form.
There is therefore a need for an image calibration apparatus and method that allows an endoscope system to be calibrated so that it can accurately portray anatomical features.
A endoscope method and system allows an endoscope system to obtain images that accurately portray anatomical features being imaged by the endoscope system. The endoscope system includes an endoscope tip that is positioned so that the internal anatomical features are within a field of view of the endoscope tip, and an image of the internal anatomical features are obtained. Either before or after the image of the internal anatomical features are obtained, a calibrating device having at least one known optical property is placed in the field of view of the endoscope tip, and an image of the calibrating device is obtained using the endoscope system. Calibration device data corresponding to the at least one known optical property of the calibration device is used with the image of the calibration device to provide calibration data. The calibration data is used to program the endoscope system and method to ensure that the endoscopically obtained image accurately portrays the imaged internal anatomical features.
An endoscope system 10 that can be used with calibration devices according to various examples of the invention is shown in
Regardless of which viewing device is used, the endoscope insertion tube 102 may also include an illumination device (not shown in
If the endoscope tip 100 has a flexible insertion tube, such as the endoscope tip 100 shown in
Although not required for imaging anatomical features, the endoscope tip 100 may also include auxiliary tubes or channels extending from the headpieces 108 to the distal end 104 of the insertion tube 102 for performing a variety of functions. One of these tubes is a wash channel (not shown) by which pressurized water can be injected through a nozzle (not shown) at the distal end 104 of the insertion tube 102 to clean the lens 108. Another channel (not shown) is used to instill air or CO2 gas to distend the hollow organ and permit visual inspection. These channels are selectively opened by actuating respective trumpet valves 134 projecting from the headpiece 108. Regardless of whether or not an endoscope tip has these channels, it can be used with various calibration devices in accordance with the invention to ensure that an endoscopic image accurately portrays imaged anatomical features.
The endoscope tip 100 may also include a biopsy channel (not shown in
As mentioned above, a variety of endoscope tips may be used with the image calibration system and method according to various examples of the invention. One such endoscope tip 150 shown in
The endoscope tip 150 also includes a second fiber-optic bundle 168 through which light is coupled to illuminate the field of view of the endoscope tip 150. A biopsy channel 170 also extends through the insertion tube 166 to an opening 174 at the distal end 164 of the insertion tube 166. As explained in greater detail below, a calibration device (not shown in
A portion of another endoscope tip 180 that can be used with the image calibration system and method according to various examples of the invention is shown in
Still another example of an endoscope tip 200 that can be used with an image calibration system and method according to various examples of the invention is shown in
In operation with the calibration system and method, the distal end 206 of the insertion tube 202 is inserted into a body cavity. The illumination optical fiber 218 transmits a beam 230 to the scanning module 210 and is shaped by the beam shaping optical element 224 to form a selected beam shape. After shaping, a shaped beam 234 is transmitted through an aperture in the center of the MEMS scanner 214, reflected off a first reflecting surface 238 of the interior of the dome 228 to the front of the scanner 214, and then reflected off of the scanner 214 and through the dome 228 to provide a scanning beam 240. The scanning beam 240 is scanned across a field-of-view (FOV) and reflected off of the interior of a body cavity. At least a portion of the reflected light from the FOV (e.g., specular reflected light and diffuse reflected light also referred to as scattered light) is collected by the detection optical fibers 218. The reflected light collected by the detection optical fibers 218 may be converted to an electrical signal by an optical-electrical converter 260, which may be a set of photodiodes. The converter 260 outputs a signal that is converted to image data by circuitry in the console 120 (
According to one example of the invention, the endoscope tip 200 may be calibrated in the same manner as the endoscope tip 180 of
A calibration device 300 according to one example of the invention is shown in
One method 330 for using the calibration device 300 will now be explained with reference to the flowchart of
An endoscopic image is then captured at step 334 by video imaging, still imaging or some other means. After the image is captured at step 334, the image is analyzed at step 336. The analysis step 336 initially includes analysis to determine if the calibration device 300 is present in the field of view of the endoscope tip. The result of this determination is used at step 338 to determine how next to proceed.
If the calibration device 300 is found not to be present at step 338, the image capture step 334 is repeated. Optionally, when step 338 determines that the calibration device 300 is not present in the field of view of the endoscope tip, an internal recalibration step 340 may be performed. This internal recalibration step 340 may include, for example, adjustment of the gain in the console 120 based on a comparison of overall or location-specific image brightness of internal body tissues or organs in the field of view of the endoscope tip. Thus, even when there is no calibration device present in the endoscope tip's field of view, circuitry in the console 120 can recognize if the image is too light or “washed out” and either reduce detector sensitivity, decrease illumination power output, or modify the image data to reduce brightness. If, on the other hand, the recalibration step 340 determines that the image is too dark, circuitry in the console 120 can increase detector sensitivity, increase illumination power output, or modify the image data to increase brightness. Methods for providing local calibration without a calibration device are described in PCT patent application No. PCT/US/2004/19996 entitled “Scanning Endoscope,” which is hereby incorporated by reference.
If the determination is made at step 338 that the calibration device 300 is present in the field of view of the endoscope tip, then a calibration step 344 is performed. Calibration data is obtained in the calibration step 344 by comparing the image of the calibration device captured at step 334 with calibration device data corresponding to the known optical properties of the calibration device 300. The calibration device data is provided to the console 120 by suitable means. For example, the calibration device data can be entered into the console 120 using the controls 128, and the entered calibration device data are stored in the console 120. The calibration device data may also be encoded into the calibration device 300 itself and read by the console 120 from an image of the calibration device 300 captured at step 334, or it may be provided to the console 120 by other means. Regardless of how the calibration device data is provided to the console 120, the console 120 compares the calibration device data to data corresponding to the image captured at step 334. Any differences in such data are indicative of deviations of the captured image data from correct image data, and these differences correspond to the calibration data. For example, the image data captured at step 334 may result in an image viewed on the monitor 126 having a color balance, contrast, brightness, sharpness, etc. that does not match the true color balance, contrast, brightness, sharpness, etc. of the calibration device 300. The calibration data corresponds to these difference between the captured image data and the calibration device data. Once the calibration data has been obtained by the above-described or other means, the calibration procedure shown in
After the calibration data have been obtained, the console 120 uses the calibration data to either modify the operation of the circuitry in the console 120. More specifically, the calibration data can be used to adjust the color balance, contrast, brightness, sharpness, etc. of the endoscope system 10 so that the image displayed on the monitor 126 accurately shows the anatomical feature.
Another example of a calibration device 350 is shown in
With further reference to
A calibrating device 400 according to another example of the invention is shown in
In operation, the cylindrical body 404 is first inserted into the biopsy channel. The catheter 414 is fed into the biopsy channel until the cylindrical body 404 protects from an opening at the distal end of the channel. Finally, the control cables are alternately retracted and extended to pivot the cylindrical body 404 within the field of view of the endoscope tip.
From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. For example, the teachings disclosed herein are generally applicable for use in scanned beam imagers such as bar code scanners in addition to scanned beam endoscope tips. Accordingly, the invention is not limited except as by the appended claims.
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