JP2006524097A - Apparatus and method for controlling light in an in vivo imaging device - Google Patents

Abstract

An apparatus and method for operating an in-vivo imaging device, for example, changing the intensity and / or duration of illumination produced by the device depending on the amount of illumination produced by the device and reflected by the device And / or gain level or other parameters can be changed. In addition, a method is provided for detecting problematic pixels in an imaging device. This method can define and exclude non-functioning pixels based on, for example, an initial short exposure that allows a threshold saturation level to be reached only for problematic pixels. Further described is a method for determining when an in-vivo device has entered the body, for example by calculating the progress of the dark frame based on the light saturation threshold of the dark frame.

Description

Background of the Invention Devices and methods for in vivo imaging of passages or cavities in the body are known in the art. Such devices can include a variety of endoscopic imaging systems and devices for imaging in various internal body cavities, among others.

  Reference is now made to FIG. FIG. 1 is a schematic view showing an embodiment of an autonomous in-vivo imaging device. The apparatus 10A generally includes an optical window 21 and an imaging system for obtaining images from inside a body cavity or lumen, such as a GI tract. The imaging system includes a lighting device 23. The lighting device 23 can include one or more individual light sources 23A, or can include only one light source 23A. The one or more light sources 23A can be white light emitting diodes (LEDs) or any other suitable light source known in the art. The apparatus 10 </ b> A includes a CMOS image sensor 24 that captures images, and an optical system 22 that focuses these images on the CMOS image sensor 24. The illumination device 23 illuminates a portion inside the body cavity through the optical window 21. The apparatus 10 </ b> A further includes a transmitter 26, an antenna 27 for transmitting a video signal of the CMOS image sensor 24, and one or more power supplies 25. The power source 25 can be any suitable power source such as, but not limited to, a silver oxide battery, a lithium battery, or other electrochemical cell having a high energy density. The power source 25 can supply power to the electric elements of the device 10A.

  In general, for gastrointestinal applications, when the device 10A is carried through the gastrointestinal (GI) tract, an imager such as, but not limited to, the multi-pixel CMOS sensor 24 of the device 10A captures an image (frame). To do. These images are processed and sent to an external receiver / recorder (not shown) carried by the patient for recording or storage. The recorded data can then be downloaded from the receiver / recorder to a computer or workstation (not shown) for display and analysis. Other systems and methods may also be appropriate.

  While the device 10A moves through the GI tract, the imager can capture frames at a constant or variable frame capture rate. For example, an imager (such as, but not limited to, the CMOS sensor 24 of FIG. 1) can capture images at a constant rate (2 Hz) of two frames per second. However, other different frame rates may be used, depending in particular on the type and characteristics of the particular imager, camera or sensor array implementation used and the available transmission bandwidth of the transmitter 26. . Downloaded images can be displayed by a workstation by playing them back at the desired frame rate. According to this implementation, a movie-like video can be played back to a specialist or doctor who investigates data, so that the doctor can examine the progress of the device via the GI tract. .

  One of the limitations of electrical imaging sensors is that their dynamic range can be limited. The dynamic range of most existing electrical imaging sensors is significantly lower than the dynamic range of the human eye. Therefore, if the imaged field of view includes both dark and bright parts, or an imaged object, the imaging sensor's dynamic range is limited, resulting in underexposure of the dark part of the field of view or of the field of view. Overexposure of bright areas or both may occur.

  Various methods can be used to increase the dynamic range of the imager. Such a method changes the amount of light reaching the imaging sensor, for example, by changing the aperture included in the imaging device or the diameter of the aperture device to increase or decrease the amount of light reaching the imaging sensor. A method for changing the exposure time, a method for changing the gain of the imager, or a method for changing the intensity of the illumination. For example, in a still camera, the intensity of the flash device can be changed during film exposure.

  When a series of continuous frames are imaged by a video camera or the like, the illumination intensity of the field of view to be imaged in the currently imaged frame is measured as a result of the light intensity measurement performed in one or more previous frames. Can be changed based on This method is based on the assumption that the lighting conditions do not suddenly change from one frame to the next.

  However, for example, in an in-vivo imaging device for imaging a GI tract, the imaging device is considered to operate at a low frame rate and moves through a body lumen (e.g., driven by peristaltic motion of the intestinal wall). Therefore, it is conceivable that the lighting state changes significantly from one frame to the next. Thus, it is conceivable that a method for controlling illumination based on previous frame measurements or data analysis is not always feasible, especially at low frame rates.

  Accordingly, there is a need for an imaging device that provides more accurate illumination that can be tailored to specific in-vivo lighting requirements or environmental conditions.

SUMMARY OF THE INVENTION Some embodiments of the present invention include an apparatus and method for operating an in-vivo imaging device, wherein the illumination generated by the device is, for example, generated by the device and reflected back to the device. Depending on the amount of illumination, the intensity and / or duration can be varied. The illumination can be controlled in this manner to further increase the efficiency.

  In accordance with some embodiments of the present invention, a method is provided for performing light control in an in vivo device. Thus, parameters such as exposure time and / or gain factor, or other parameters for conveying recorded light can be changed. For example, the gain factor can be changed as a function of the light saturation level measured at at least one interval within the frame exposure period. In this manner, the in-vivo device can prevent overexposure and underexposure in addition to assisting the exposure to end after sufficient exposure is obtained.

  In accordance with some embodiments of the present invention, a method is provided for detecting problematic pixels in an imaging device. This method can define and / or exclude problematic or non-functional pixels, for example, based on an initial short exposure that allows reaching a threshold saturation level only for the problematic pixels.

  In accordance with some embodiments of the present invention, a method is provided for determining when an in-vivo imaging device has entered a particular part of the body. Therefore, environmental parameters such as pH level and temperature level can be detected using the environmental measuring device. Using the results recorded from these measuring devices, it is possible to define the location, region, organ, etc., where the position of the in-vivo device is thought to have been identified or thought to have been identified. The mode of this device can be changed according to the resulting resolution.

  In accordance with some embodiments of the present invention, a method is provided for determining when an in-vivo imaging device has entered the body using a dark frame. For example, if a dark frame requires a significant gain factor to obtain full exposure, the device can be defined as being in the body (dark environment). The mode of this device can be changed according to the resulting resolution.

  The present invention is described herein for purposes of illustration only by reference to the accompanying drawings, in which like components are designated with like reference numerals. It will be understood that these drawings are presented for purposes of illustration only and are not meant to be limiting.

DETAILED DESCRIPTION OF THE INVENTION In this specification, various aspects of the present invention will be described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without the specific details presented in this specification. Furthermore, well-known features may be omitted or simplified in order not to obscure the present invention.

  Some embodiments of the invention are based on the control of the illumination provided by the in-vivo imaging device, in particular based on light measurements made within one frame capture time or part of its duration.

  The embodiments of the invention shown below are adapted for imaging of the gastrointestinal (GI) tract, but the devices and methods disclosed herein are adapted to image other cavities or spaces in the body. Note that you can let it.

  Reference is now made to FIG. FIG. 2 is a schematic block diagram showing a part of an in-vivo imaging device having an automatic illumination control system according to an embodiment of the present invention. Device 30 is disclosed with respect to device 10A of FIG. 1, or US Pat. No. 5,604,531 to Iddan et al. Or Glukovsky, both of which are hereby incorporated by reference in their entirety. (Glukhovsky) can be configured as a swallowable video capsule disclosed in co-pending PCT patent application publication number WO 01/65995. However, the system and method of the present invention may be used with other in vivo imaging devices.

  The device 30 may include an imaging device 32 that is adapted to image the GI tract. The imaging device 32 is the CMOS imaging sensor 24 of FIG. 1 or the like, but may include an imaging sensor (not shown in detail) that is not limited thereto. However, the imaging device 32 may include any other suitable type of imaging sensor known in the art. The imaging device 32 may also include one or more lenses (not shown), one or more compound lens assemblies (not shown), one or more suitable optical filters (not shown), or known in the art. 1 such as any other suitable optical element (not shown) adapted to focus the image of the GI tract onto the imaging sensor as disclosed above with respect to the optical device 22 of FIG. An optical device 32A including one or more optical elements (not shown) may also be included.

  The optical device 32A is attached to, fixed to, formed on, or adjacent to a light-sensitive pixel (not shown) of an imager known in the art, or the like (not shown). One or more optical elements (not shown) that are integrated with the imaging device 32A.

  Such as, but not limited to, a receiver / recorder disclosed in US Pat. No. 5,604,531 to Idan et al. Or PCT Patent Application Publication No. WO 01/65995, co-pending to Gurkovsky et al. In order to transmit the image captured by the imaging device 32 to an external receiving device (not shown) in a telemetric manner, the device 30 also includes a telemetry device 34 connected to the imaging device 32 in an appropriate manner. obtain.

  The device 30 may also include a controller / processor device 36 connected in an appropriate manner to the imaging device 32 to control the operation of the imaging device 32. The controller / processor device 36 may include any suitable type of controller, such as, but not limited to, an analog controller or a digital controller such as a data processor, microprocessor, microcontroller, or digital signal processor (DSP). . The controller / processor device 36 may also include hybrid analog / digital circuitry known in the art. Controller / processor device 36 may be connected to telemetry device 34 in an appropriate manner to control transmission of image frames by telemetry device 34.

  The controller / processor device 36 can be (optionally) connected to the imaging device 32 in an appropriate manner to transmit control signals to the imaging device 32. Thus, the controller / processor device 36 can (optionally) control the transmission of image data from the imaging device 32 to the telemetry device 34.

  The device 30 may also include a lighting device 38 for illuminating the GI tract. The illuminator 38 may include one or more separate light sources 38A, 38B-38N, or may include only one light source. Such a light source can be, for example, the light source 23A of FIG. 1, but is not limited thereto. The light sources 38A, 38B-38N of the illuminating device 38 may be white light emitting diodes such as the light source disclosed in PCT Patent Application Publication No. WO 01/65995, co-pending to Gurkovsky et al. However, the light sources 38A and 38B to 38N of the illumination device 38 may be, but are not limited to, an incandescent lamp, a flashlight, a gas discharge lamp, or any other appropriate light source known in the art.

  Note that, in accordance with another embodiment of the present invention, the in-vivo imaging device may include a single light source (not shown).

  The apparatus 30 may also include an illumination control device 40 that is connected in an appropriate manner to the light sources 38A, 38B-38N of the illuminator 38 to control energization of the light sources 38A, 38B-38N of the illuminator 38. The lighting controller 40, as will be disclosed in detail later, to turn on or off one or more light sources 38A, 38B-38N and / or light generated by one or more light sources 38A, 38B-38N. Can be used to control the intensity of the.

  The controller / processor device 36 can be connected to the lighting control device 40 in an appropriate manner to transmit control signals to the lighting control device 40 (optionally). Such a control signal can be used to synchronize or timing the energization of the light sources 38A, 38B, and 38N in the illumination device 38 with reference to the imaging period or period of the imaging device 32. The lighting controller 40 may be (optionally) integrated into the controller / processor device 36 or may be a separate controller. In some embodiments, the lighting control device 40 and / or the controller / processor device 36 may be part of the telemetry device 34.

The device 30 may further include a light detection device 42 for detecting light generated by the lighting device 38 and reflected from the wall of the GI tract. The light sensing device 42 may include a single light sensitive device or light sensor, such as, but not limited to, a photodiode, a phototransistor, or a plurality of individual light sensitive devices or light sensors. Other types of photosensors having suitable characteristics known in the art can also be used to implement the photodetection device of an embodiment of the invention.

  The light detection device 42 is connected to the illumination control device 40 in an appropriate manner, and a signal representing the intensity of light reflected from the wall of the gastrointestinal tract (or any other object in the field of view of the imaging device 32), It can be given to the lighting control device 40. In operation, the lighting control device 40 can process the signal received from the light sensing device 42 and, as disclosed in detail above and below, based on the processed signal, the light sources 38A, 38B-38N. The operation can be controlled.

  The device 30 may also include a power supply 44 for supplying power to the various components of the device 30. Note that for clarity of illustration, the connection between the power source 44 and the circuitry or components of the device 30 that receives power from the power source 44 is not shown in detail. The power source 44 may be an internal power source similar to the power source 25 of the device 10A, such as a battery or other power source. However, if the device 30 is configured as an insertable device (eg, an endoscope-like device, a catheter-like device, or any other type of in-vivo imaging device known in the art), the power source 44. May be an external power supply that can be located outside of the device 30 (such an external configuration is not shown in FIG. 2 for clarity of explanation). In such embodiments having an external power supply (not shown), the external power supply (not shown) requires power at the imaging device via a suitable electrical conductor (not shown) such as an insulated wire. It can be connected to various components.

  For an autonomous or swallowable in-vivo imaging device such as device 10A, power source 25 is preferably (although not necessarily) a compact power source for supplying direct current (DC), while an external power source is alternating current ( AC) or any other suitable power source known in the art, including but not limited to a power source supplying direct current, or even a power source coupled to the mains as known in the art Please note that it is good.

  Various functions and processes performed by the swallowable in-vivo imaging device may be performed, for example, by a processor device (such as device 36 of FIG. 2). These functions and processes may be performed only by the processor unit 36 and / or alternative devices such as the lighting control device 40, telemetry device 34, light sensing device 42, imaging device 32, etc., or these devices. May be implemented by any combination of Various devices may be optionally integrated within the processor device 36, so that it can be said that the processor device performs any of the functions and processes described herein. The methods and processes described herein may also be implemented in other sensing devices having other structures and other components.

  Reference is now made to FIGS. FIG. 3 is a schematic cross-sectional view of a portion of an in-vivo imaging device having an automatic illumination control system and four light sources according to one embodiment of the present invention. FIG. 4 is a schematic front view of the apparatus shown in FIG.

  Device 60 (only a portion of which is shown in FIG. 3) includes an imaging device 64. The imaging device 64 may be similar to the imaging device 32 of FIG. 2 or the imaging device 24 of FIG. Preferably, the imaging device 64 may be a CMOS imaging device, but other different types of imaging devices may be used. The imaging device 64 may include a CMOS imager circuit, as is known in the art, for example, US Pat. No. 5,604,531 to Idan et al. Or a co-pending PCT patent to Gurkovsky et al. Other types of support and / or control circuits known in the art, disclosed in application publication number WO 01/65995, may be included therein. The device 60 also includes an optical device 62 that may include the lens or optical elements disclosed above for the optical device 22 of FIG. 1 and the optical device 32A of FIG.

  The device 60 may include a lighting device 63 that may include four light sources 63A, 63B, 63C, and 63D that may be disposed within the device 60 shown in FIG. The light sources 63A, 63B, 63C, and 63D may be, for example, co-pending US patent applications, PCT patent applications, publication number WO 01/65995 to Gurofsky et al., Or white LED light sources. . It can also be any other suitable type of light source known in the art or disclosed above, including a band-limited light source, a monochromatic light source, an infrared light source, etc. .

  According to one embodiment of the present invention, the light sources 63A, 63B, 63C and 63D are shown to be identical, but other embodiments of the present invention can be implemented with multiple light sources that may not be identical. Please pay attention to. Some light sources may have a spectral distribution different from that of other light sources. For example, of the light sources in the same device, one of the light sources may be a red LED, another light source may be a blue LED, and another light source may be a yellow LED. Other configurations of the light source are also possible.

  The device 60 may also include a baffle 70 that may be conical or have any other suitable shape. The baffle 70 may have an opening 70A therein. The baffle 70 can be interposed between the light sources 63A, 63B, 63C, and 63D and the optical device 62 to reduce the amount of light that comes directly from the light sources 63A, 63B, 63C, and 63D and enters the opening 70A. be able to. The device 60 may include a transparent optical dome 61 similar to the optical dome 21 of FIG. The optical dome 61 is formed of a suitable transparent plastic material or glass, or suitable with sufficient transparency for at least part of the wavelength of light generated by the light sources 63A, 63B, 63C and 63D. It can be made of any other suitable material that allows accurate imaging.

  Device 60 may further include at least one light sensing device 67 for sensing light reflected from or diffused by intestinal wall 76. The light detection device can be attached to the baffle 70 so that the light detection portion 67 </ b> A faces the optical dome 61. Preferably, the light detection device 67 represents the amount of light entering the opening 70A of the baffle 70, or at a position where the light detection device 67 can detect the amount of light proportional to the amount of light. Although it can be located on the surface, it need not be. This means that when the illuminated object is semi-diffusive (the intestinal surface is likely) and the size of the light sensing device 67 and the distance from the imaging sensor axis 75 is capsule-like. This is considered to be applicable when the diameter is smaller than the diameter D of the device 67.

  Device 60 (FIG. 3) is shown adjacent to intestinal wall 76. In operation, the light beam 72 generated by the light sources 63A, 63B, 63C and 63D can penetrate the optical dome 61 and be reflected from the intestinal wall 76. A part of the reflected light beam 74 can reach the light detection device 67. Other portions (not shown) of the reflected light rays can reach the opening 70A, pass through the optical device 62, and be focused on the imaging device 64.

  The amount of light measured by the light detection device 67 can be proportional to the amount of light entering the opening 70A. Therefore, the light output of the light sources 63A, 63B, 63C and 63D can be determined using the measured value of the intensity of the light reaching the light detection device 67, as will be disclosed in detail below.

The device 60 also includes a lighting control device 40A. The illumination control device 40A is coupled to the light detection device 67 and the illumination device 63 in an appropriate manner. The illumination control device 40A can process the signal received from the light detection device 67 to control the light sources 63A, 63B, 63C, and 63D, as disclosed in detail below.

  The device 60 may also include a radio transmitter device (not shown in FIG. 3) and an antenna (not shown in FIG. 3), such as but not limited to the transmitter 26 and antenna 27 of FIG. Any suitable telemetry device (such as, but not limited to, telemetry device 34 of FIG. 2). The telemetry device wirelessly transmits data and control signals to an external receiver / recorder (not shown in FIG. 3) (and optionally from the external receiver / recorder) as disclosed in detail above ( It can also be a transmitter or a transceiver for receiving arbitrarily. The device 60 may also include one or more power sources, such as the power source 25 of FIG. 1, or any other suitable power source known in the art.

  Reference is now made to FIG. FIG. 5 is a schematic diagram illustrating a method for timing illumination and image capture in an in-vivo imaging device having a certain illumination duration. This method of timing can be specific to an imaging device having a CMOS imager, but can also be used in devices having other types of imagers.

  The period or period of image capture starts at time T. The first image capture cycle ends at time T1 and has a duration ΔT1. The second image capture cycle starts at time T1 and ends at time T2, and has a duration ΔT1. Each of the imaging cycles or periods may include two parts: a lighting period 90 having a duration ΔT2 and a dark period 92 having a duration ΔT3. The illumination period 90 is represented by the shaded bar-shaped portion in FIG. During the illumination period 90 of each imaging cycle, the illumination device (such as, but not limited to, the illumination device 38 of FIG. 2 or the illumination device 63 of FIG. 3) is turned on to illuminate the intestinal wall. Give light. During the dark period 92 of each imaging cycle, the illuminating device (such as, but not limited to, the illuminating device 38 of FIG. 2 or the illuminating device 63 of FIG. 3) is switched off and does not provide light.

  The dark period 92 or a portion thereof may be used to capture an image from the imager, process an imager output signal, and output signal, for example, by scanning the imager pixels as disclosed above. Or it can be used to send the processed output signal to an external receiver or receiver / recorder device.

  For the sake of simplicity, the diagram of FIG. 5 shows a case where the duration of the image capture cycle is constant and the imaging is performed at a constant frame rate, but this is not necessarily the case. Please be careful. Thus, the frame rate, i.e. the duration of the image capture cycle, can change during imaging depending on the measured parameters, e.g.

  In general, different types of light control methods can be used to ensure proper image capture.

  In the first method, while the illumination device 63 is illuminating the target tissue, the amount of light hitting the light detection device 67 is continuously measured and recorded, and the cumulative total number of photons detected by the light detection device 67 is measured. A cumulative value representing can be provided. When this accumulated value reaches a certain value, the lighting device 63 can be turned off by switching off the light sources 63A, 63B, 63C and 63D included in the lighting device 63. In this way, the device 60 ensures that the lighting device 63 can be turned off when the measured amount of light is sufficient (on average) to produce a properly exposed frame. To do.

One advantage of the first method is that when the light sources (such as light sources 63A, 63B, 63C and 63D) are operating at their maximum light output capability or near maximum light output capability in this way. By switching off, energy can be saved compared to energy consumption within a certain duration of the illumination period (such as illumination period 90 in FIG. 5).

  Another advantage of the first method is that the duration of the illumination period within the imaging cycle can be reduced by the first method compared to using a fixed illumination period. In mobile imaging devices such as device 60, it is ideally desirable to make the illumination period as short as possible in practice. This is to prevent or reduce image blur due to the device 60 moving in the GI tract. Therefore, in general (assuming that sufficient light is generated by the illuminating device and adequate imager exposure is ensured), with a mobile imaging device, the shorter the illumination period, the resulting image will be It becomes clear.

  This is thought to be somewhat similar to increasing the shutter speed and reducing the duration of exposure in a normal camera operated by a shutter to prevent blurring of moving objects or images. Embodiments of the invention differ in that there is generally no shutter and the illumination period is shortened in a controllable manner to reduce image smearing as the device moves through the GI tract.

  Reference is now made to FIGS. FIG. 6 is a schematic diagram illustrating one possible configuration for a lighting control device coupled to a light sensing photodiode and a light emitting diode, in accordance with one embodiment of the present invention. FIG. 7 is a schematic diagram illustrating in detail the lighting control apparatus of FIG. 6 according to one embodiment of the present invention.

  The illumination control device 40B of FIG. 6 can be connected in an appropriate manner to a photodiode 67B that can operate as a light detection device. Any other suitable sensing device or light sensor may be used. The lighting control device 40B may be connected to the light emitting diode (LED) 63E in an appropriate manner. LED 63E may be a white LED as disclosed above, or any other type of LED suitable for illuminating a target to be imaged (such as the gastrointestinal wall). The lighting control device 40B can receive a current signal from the photodiode 67B. The received signal may be proportional to the intensity of light (schematically illustrated by arrow 81) impinging on photodiode 67B. The illumination control 40B can process the received signal to determine the amount of light that illuminated the photodiode 67B during the duration of the light measurement period. The illumination control 40B can control energization to the LED 63E based on the amount of light that illuminates the photodiode 67B during the duration of the light measurement period. Examples of types of processing and energization control are disclosed in detail below. The illumination control device 40B can receive control signals from other circuit components included in the in-vivo imaging device. For example, the control signals may include timing and / or synchronization signals, on / off switching signals, reset signals, and the like.

  The light detection device and light generation device may be any suitable light generation device or light detection device other than a diode.

  FIG. 7 shows one possible embodiment of the lighting control device 40B. The lighting control device 40B may include, for example, an integrator device 80, a comparator device 82, and an LED driver device 84. The integrator device 80 is coupled to the photodiode 67B, receives a signal indicating the intensity of light hitting the photodiode 67B from the photodiode 67B, and records and integrates the amount of light hitting the photodiode 67B. Integrator device 80 may be connected to comparator device 82 in any suitable manner.

The integrator device 80 can record and integrate the amount of light impinging on the photodiode 67B, integrate the received signal, and output the integrated signal to the comparator device 82. The integrated signal may be proportional to or may indicate the cumulative number of photons that hit the photodiode 67B over the period of integration. Comparator device 80 may be connected to LED driver device 84 in any suitable manner. The comparator device 80 can continuously compare the value of the integrated signal with a preset threshold value. When the value of the integrated signal is equal to the threshold value, the comparator device 82 controls the LED driver device 84 to stop the operation of the LED 63E by switching off the power to the LED 63E.

  Therefore, the illumination control device 40A can be configured and operated in the same manner as the illumination control device 40B of FIGS.

  The circuit shown in FIG. 7 can be implemented as an analog circuit, but as disclosed in detail below (with reference to FIG. 11), in implementing a lighting control device, a digital circuit and / or hybrid Note that analog / digital circuitry may be used.

  Reference is now made to FIG. FIG. 8 is a schematic diagram useful for understanding how to time illumination and image capture in an in-vivo imaging device having a controlled variable illumination duration, according to one embodiment.

The period or period of image capture starts at time T. The first image capture period ends at time T1 and has a duration ΔT1. The second image capture period starts at time T1 and ends at time T2, and has a duration ΔT1. In each imaging cycle, the period having duration ΔT4 defines the maximum acceptable illumination period. The maximum acceptable illumination period ΔT4 may generally be short enough that the device 60 moves in the GI tract to allow imaging with no excessive blur or haze of images. Time T _M is the end time of the maximum allowable illumination period ΔT4 with respect to the start time of the first imaging cycle.

  The maximum acceptable illumination period ΔT4 is in particular typical or average (or maximum) obtained by an imaging device in the GI tract (as can be determined empirically with multiple devices used in different patients). It is preset at the factory before considering the speed, the type of image sensor (for example, the CMO sensor 64 of the device 50), the scanning time requirement, and other manufacturing and timing considerations. obtain. According to one implementation of the present invention, when ΔT1 = 0.5 seconds, which is an imaging of two frames per second, the duration of ΔT4 has a value in the range of 20-30 milliseconds. Can be set. However, this duration is shown as an example only and ΔT4 may have other different values. In general, by using an acceptable maximum illumination period ΔT4 of less than 30 milliseconds, most captured image frames are acceptable without excessive degradation due to image haze as the imaging device moves through the GI tract. Image quality can be produced.

  The period ΔT5 is defined as the difference between the total duration ΔT1 of the imaging cycle and the maximum allowable illumination period ΔT4 (ΔT5 = ΔT1−ΔT4).

  At the start time T of the first imaging cycle, the illumination device (such as, but not limited to, the illumination device 63 in FIG. 3) is turned on to provide light for illuminating the intestinal wall. The light detection device 67 detects the light reflected and / or diffused from the intestinal wall 76 and gives a signal to the illumination control device 40A of the device 60. This signal may be proportional to the average amount of light entering the aperture 70A. The signal provided by the light sensing device 67 may be integrated by the lighting control device 40A, as disclosed in detail above with respect to the lighting control device 40B of FIGS.

The integrated signal can be compared to a preset threshold (eg, by a comparator such as comparator device 82 of FIG. 7). When the integrated signal is equal to the threshold value, the illumination control device 40A stops the operation of the light sources 63A, 63B, 63C, and 63D of the illumination device 63. Time TE ₁ is a time when the illumination control device turns off the light sources 63A, 63B, 63C, and 63D within the first imaging cycle. The time interval starting at time T and ending at time TE ₁ is an illumination period 94 (represented by a shaded bar-like portion with 94) for the first imaging period. The illumination period 94 has a duration of ΔT6. It can be recognized that ΔT6 <ΔT4 with respect to the first imaging cycle.

After time TE ₁ , scanning of the pixel CMOS sensor 64 can begin, and the pixel data (and possibly other data) is sent by the transmitter of device 60 (not shown in FIG. 3) or a telemetry device. Can be sent.

Preferably, the scanning (reading) of the pixels of the CMOS sensor 64 can be started as early as time TE ₁ when the illumination ends. For example, the illumination control unit 40A sends a control signal to the CMOS sensor at time TE _1, it is possible to start scanning the pixels of the CMOS sensor 64. However, pixel scanning is preset after time T _M , which is the end time of the maximum allowable illumination period ΔT4, if sufficient time is available for pixel scanning and data transmission operations. It is also possible to start at a designated time. According to one embodiment, if the beginning of the readout time is fixed at eg T _M , a simpler implementation of the receiving device may be possible.

  At the start time T1 of the second imaging cycle, the illumination device 63 is turned on again. The light detection device 67 detects the light reflected and / or diffused from the intestinal wall 76 and gives a signal to the illumination control device 40A of the device 60. This signal may be proportional to the average amount of light entering the aperture 70A.

  The signal provided by the light sensing device 67 can be integrated and compared to a threshold as disclosed above for the first imaging period. When the integrated signal is equal to the threshold value, the illumination control device 40A turns off the light sources 63A, 63B, 63C, and 63D of the illumination device 63. However, in the specific schematic example shown in FIG. 8, the intensity of light reaching the light detection device 67 in the second imaging cycle is greater than the intensity of light reaching the light detection device 67 in the first imaging cycle. Is also low.

  Such differences in the illumination intensity or intensity versus time graphs between different imaging cycles are particularly the movement of the device 60 away from the intestinal wall 76, the change in the position or orientation of the device 60 relative to the intestinal wall 76, or the device This may be due to a change in the characteristics of light absorption, light reflection, or light diffusion in the portion of the intestinal wall 76 in the field of view of 60.

Therefore, it takes longer for the integrated signal output of the integrator device to reach the threshold. Therefore, the lighting control device 40A turns off the lighting device 63 at the time TE ₂ (note that TE ₂ > TE ₁ ).

Periods ending time TE ₂ beginning at time T1 is the illumination period 96 for the second imaging cycle. The illumination period 96 (represented by a shaded bar with 96) has a duration ΔT7. It can be recognized that ΔT7 <ΔT4 with respect to the second imaging cycle.

  Accordingly, it is conceivable that the duration of the illumination period within different imaging cycles will vary, and in particular may depend on the intensity of light reaching the light detection device 67.

After time TE _2, it is possible to start scanning the pixels of the CMOS sensor 64, (other data and possibly) pixel data, as disclosed in detail above with respect to the first imaging cycle of Fig. 8 Can be sent.

  For the sake of simplicity, the diagram of FIG. 8 shows the case where the duration ΔT1 of the image capture period is constant and the imaging is performed at a constant frame rate, but this is not necessarily enforced. Please pay attention to. Thus, the frame rate, and thus the duration of the image capture period ΔT1, may change during imaging depending on measured parameters such as the speed of the imaging device in the gastrointestinal tract. In such cases, the duration of the imaging cycle can be shortened or extended in response to the measured speed of the device 60 to increase or decrease the frame rate, respectively.

  For example, co-pending US patent application Ser. No. 09 filed May 15, 2000, commonly assigned to the assignee of the present application, which is incorporated herein by reference in its entirety for all purposes. No./571,326 specifically discloses an apparatus and method for controlling the frame rate of an in-vivo imaging device.

  The automatic lighting control method disclosed above can be adapted for use with devices having variable frame rates. Such adaptation can take into account the various durations of the imaging cycle, and implementations are particularly useful for the amount of time required to complete the scanning of the pixels and the transmission of data, which the device 60 uses. It may depend on the available amount of power that can be done, and other considerations.

  A simple way to adapt this method is to limit the maximum frame rate of the imaging device, leaving enough time for pixel scanning and data transmission within the period even when the maximum frame rate is used. It is thought that it is to be.

  Reference is now made to FIG. FIG. 9 is a schematic diagram useful for understanding how to time illumination and image capture in an in-vivo imaging device with variable frame rate and variable controlled illumination duration.

The first imaging cycle in FIG. 9 is the same as the first imaging cycle in FIG. 8, but the duration of the illumination period 98 in FIG. 9 (indicated by a shaded bar-like portion with 98 attached). The difference is that it is longer than the duration of the illumination period 94 in FIG. The first imaging cycle in FIG. 9 starts at time T and ends at time T1, and has a duration ΔT1. Time T _M indicates the end of the maximum allowable illumination period ΔT4. The second imaging cycle in FIG. 9 starts at time T1 and ends at time T3. The duration ΔT8 of the second imaging cycle is shorter than the duration ΔT1 of the first imaging cycle (ΔT8 <ΔT1). The duration ΔT8 of the second imaging cycle corresponds to the maximum frame rate that can be used by the imaging device. The illumination period 100 of the second imaging cycle (in FIG. 9, 100 is represented by a shaded bar), depending on the intensity of the light, as disclosed in detail above. Timed by the device. Period 102 (represented by a bar with 102 and a dot) represents the amount of time ΔT9 required to scan the imager pixels and transmit the scanned frame data. . T _M represents the end time of the maximum allowable illumination period with respect to the start time of each imaging cycle. Thus, when the frame rate is increased, there is sufficient time to scan the pixels and transmit data, even at the maximum possible frame rate.

In general, in an example of an in-vivo imaging device having a constant frame rate, a CMOS sensor having about 66,000 pixels (such as, but not limited to, a CMOS sensor arranged in a 256 × 256 pixel array). The time required to scan a number of pixels and transmit a digital (serial) data signal to an external receiver recorder may be approximately 0.4 seconds (scanning and data transmission of approximately 6 microseconds per pixel) Note that time is assumed).
Thus, assuming a maximum illumination period of about 20-30 milliseconds, the frame rate is not expected to be significantly higher than 2 frames per second. For example, alternative frame rates may be used to achieve different read rates.

  However, it may be possible to substantially reduce the time required for pixel scanning and data transmission. For example, by increasing the clock speed of a CMOS pixel array, it may be possible to reduce the time required to scan an individual frame to 3 milliseconds or less than 3 milliseconds. In addition, the data transfer rate of the transmitter 26 can be increased to further reduce the overall time required to scan the pixels of the array and transmit the pixel data to an external receiver / recorder.

  Thus, in-vivo imaging devices with variable frame rates can be realized that may be possible not only for devices with a constant frame rate, but also frame rates of about 4-8 frames per second or higher.

  Realizes the method disclosed above for turning off the illuminator when the integrated output of the light detector reaches a threshold adapted to ensure good and average image quality In doing so, the designer may have a tendency to operate the lighting device (eg, the lighting device 63 of FIG. 3) in the vicinity of the maximum available light output capability. This is considered advantageous. This is because the sharpness of the image can be increased by reducing the duration of the illumination period and reducing the haze of the image induced by movement.

  It may not always be possible or always desirable to operate the lighting device near the maximum light output capability possible. Therefore, it may be desirable to start the operation of the lighting device 63 with a predetermined light output smaller than the maximum light output of the lighting device 63.

  In the second lighting control method, the lighting device 63 of FIG. 3 can first operate at the first light output level at the beginning of each lighting cycle. Photodetector 67 can be used to measure the amount of light during a short illumination sampling period.

  Reference is now made to FIGS. 10A, 10B and 10C. FIG. 10A is a timing diagram schematically showing an imaging cycle of an in-vivo imaging device using an automatic illumination control method according to another embodiment of the present invention. FIG. 10B is an exemplary schematic diagram illustrating an example of light intensity as a function of time that is possible using the automatic lighting control method illustrated in FIG. 10A. FIG. 10C is a schematic graph illustrating another example of light intensity as a function of time that is possible when using the automatic illumination control method illustrated in FIG. 10A.

  10A, 10B, and 10C, the horizontal axis of the graph represents time in arbitrary units. 10B and 10C, the vertical axis represents the intensity I of the light output by the illumination device 63 (FIG. 3).

  The automatic lighting control method shown in FIG. 10A works by using a lighting sampling period 104 that is included within the total lighting period 108. The imaging period 110 includes an entire illumination period 108 and a dark period 112. The lighting device 63 can illuminate the intestinal wall 76 within the duration of the entire lighting period 108. The dark period 112 can be used to scan the pixels of the CMOS imager 64 to process and transmit image data, as disclosed in detail above.

The entire illumination period of the imaging cycle starts at time T and ends at time T _M. The time T _M is fixed with reference to the start time T of the imaging period 110 and represents the maximum allowable illumination time. In fact, the time T _M can be selected to reduce the likelihood of the image becoming hazy, as explained above. For example, the time T _M can be selected as 20 milliseconds from the start time T of the imaging period 110 (ie, the duration of the entire illumination period 108 can be set to 30 milliseconds), but the time T _M And other larger or smaller values of the total illumination period 108 may be used.

The total illumination period 108 may include an illumination sampling period 104 and a main illumination period 106. The illumination sampling period 104 starts at time T and ends at time T _S. The main illumination period 106 starts at time T _S and ends at time T _M.

In an exemplary embodiment of this method, the duration of the illumination sampling period 104 can be set to about 2-5 milliseconds, in particular, the type and characteristics of the light sensing device 67, its sensitivity to light, its signal The noise to noise ratio (S / N), the intensity I ₁ at which the illuminator 63 operates during the illumination sampling period 104, and other durations larger or shorter depending on other implementations and manufacturing considerations A time value may be used.

Returning to FIGS. 10B and 10C, during the illumination sampling period 104, the illuminator 63 operates such that the light intensity is I ₁ . The light detection 67 can detect light reflected from the intestinal wall 76 and diffused by the intestinal wall 76. The illumination control device 40A can integrate the intensity signal to determine the amount Q of light that reaches the light detection device 67 within the duration of the illumination sampling period 104. The lighting controller 40A then uses the lighting device 63 during the duration of the main lighting period 106 to provide an appropriate and average exposure of the CMOS sensor 64 from the value Q and the known duration of the main lighting period 106. The light intensity I _N that is required to operate can be calculated. In one embodiment, the approximate total amount of light received is either kept substantially constant throughout a set of imaging periods or is kept within a specific target range. The calculation, for example, subtracts the amount of light recorded during the sampling period 104 from the amount of light that is received or desired to be applied, and results in a period corresponding to the main illumination period 106. Can be done by dividing One possible way to perform this calculation uses Equation 1 as follows:

I _N = (Q _T −Q) / ΔT _MAIN Equation 1
here,
ΔT _MAIN is the duration of the main illumination period 106, and Q _T is the total amount of light that must reach the light detection device 67 within the imaging period to ensure proper and average exposure of the CMOS sensor 64. Q is the amount of light that reaches the light detection device 67 within the duration of the illumination sampling period 104 of the imaging cycle.

Note that the value of Q _T can be determined empirically.

FIG. 10B schematically shows a graph showing the intensity of light produced by the illumination device 63 as a function of time for an exemplary imaging period. During the illumination sampling period 104, the light intensity has the value I ₁ . After the end of the illumination sampling period 104, the light intensity I _N = I ₂ is calculated as disclosed in Equation 1 above or by using any other suitable type of analog or digital calculation Can do.

For example, if the calculation is performed digitally by the controller / processor 36 of FIG. 2, the value of I _N can be calculated in a very short time (eg, in less than 1 microsecond, etc.) compared to the duration of the main illumination period 106. .

If the calculation of I _N is performed by the lighting control device 40 of FIG. 2, the lighting control device 40B of FIG. 6, or an analog circuit (not shown) that can be included in the lighting control device 40A of FIG. It is conceivable that it is also shorter than the duration of the main lighting period 106.

After the calculation of I ₂ with respect to the imaging cycle shown in FIG. 10B is completed, the illumination control device 40A can change the light output intensity of the illumination device of the imaging device to I ₂ . This is included in the lighting controller 40A, for example, by increasing the amount of current output from the LED driver device 84 of FIG. 7 or to supply current to the light sources 63A, 63B, 63C and 63D. This can be done by increasing the amount of current output from one or more LED driver devices (not shown in detail) that may be possible. At the end of the main illumination period 108 (time T _M ), the illumination control device 40A can switch the illumination device 63 off until time T1, which is the start time of a new imaging cycle (not shown). At the start of a new imaging cycle, the light intensity is again switched to the value I ₁ and a new illumination sampling period begins.

FIG. 10C schematically shows a graph showing the intensity of light produced by the illuminator 63 as a function of time for another different exemplary imaging period. The illumination intensity I ₁ is used throughout the illumination sampling period 104 as disclosed above. However, in this imaging cycle, the Q value measured during the illumination sampling period 104 is larger than the Q value measured during the illumination sampling period of FIG. 10B. This can occur, for example, by movement of the position of the imaging device 60 relative to the intestinal wall 76. Therefore, the calculated value I ₃ is smaller than the value of I ₂ of the imaging period shown in FIG. 10B. Further, the value of I ₃ is smaller than the value of I ₁ . Therefore, the intensity of light emitted by the illuminating device 63 during the main illumination period 106 shown in FIG. 10C is lower than the intensity of light emitted by the illuminating device 63 during the illumination sampling period 104 of FIG. 10C.

If the calculated value of I ₃ is equal to the value of I ₁ (not shown in FIGS. 10B-10C), the intensity of illumination is the initial value I ₁ during the duration of the entire illumination period 108. Note that the illumination intensity change is not made at time T _M.

An advantage of the second lighting control method disclosed above is that this method can prevent the lighting device 63 from operating at its maximum light output intensity at least initially. This may be useful for enhancing the performance of a power source such as, for example, power source 25 of FIG. 1, and may extend its useful operating life. It is known in the art that many batteries and electrochemical cells do not function optimally when operated near their maximum current output. With the second illumination method, the light sources (such as light sources 63A, 63B, 63C and 63D in FIG. 3) are initially operated at a light intensity I ₁ which can be a fraction of their maximum output light intensity. Thus, in cases where it has been determined that the maximum light output intensity is not required for the current frame capture, the light source has a second light intensity level (eg, a light intensity lower than the light intensity level I ₁ ). Level I ₃ etc.). Therefore, the second illumination control method can reduce the current required to operate the lighting device 63 by being drawn from the battery or other power source of the imaging device, and thereby the battery used in the imaging device. Or the useful operating life of other power sources can be extended. According to one embodiment, both methods (variable duration and variable intensity) can be combined.

  It will be appreciated by those skilled in the art that embodiments of the present invention are not limited to using one light sensing element and / or one light source. In addition, it will be appreciated that the light sensing element may include a photodetector that is separate from or part of the imager.

  Reference is now made to FIG. FIG. 11 is a schematic diagram showing an illumination control apparatus for controlling a plurality of light sources according to one embodiment of the present invention.

  The lighting control device 120 includes a plurality of light detection devices 122A, 122B,... 122N appropriately interfaced with a plurality of analog-to-digital (A / D) conversion devices 124A, 124B,. The A / D conversion device is connected to the processing device 126 in an appropriate manner. The processing device 126 is connected in an appropriate manner to the plurality of LED drivers 128A, 128B,... 128N connected to the plurality of LED light sources 130A, 130B,.

  Signals representing the intensity of light detected by the light detection devices 122A, 122B,... 122N are respectively supplied to A / D conversion devices 124A, 124B,... 124N, and these conversion devices output digitized signals. To do. The digitized signal may be received by a processing unit 126 that can process the signal. For example, the processor 136 may perform signal integration to calculate the amount of light detected by one or more of the light detectors 122A, 122B,. The calculated amount of light can be the combined amount of light detected by all of the light detection devices 122A, 122B,... 122N, or each of the light detection devices 122A, 122B,. Can be an individual amount of light calculated separately for each of the light sensing devices.

  The processing unit 136 can further process the calculated amount of light to provide control signals to the LED drivers 128A, 128B,... 128N, which can then be individually or combined to provide LED signals. An appropriate current can be applied to the light sources 130A, 130B,. According to one embodiment of the invention, each sensor can be directly associated with one or more light sources.

  According to some embodiments of the invention, individual control of the illumination source may be possible by using special control pixels. These control pixels can be adapted for high speed readout, which is well known in the art. It is conceivable that the fast readout procedure does not reset the pixel value.

  Note that the lighting control device 120 of FIG. 11 may operate using different methods of processing and control.

  In accordance with one embodiment of the present invention, all of the light detection devices 122A, 122B,... 122N can be used as one light detection element, and the light sources 130A, 130B are calculated using the total amount of light. ... Controls all operations of 130N simultaneously. In this embodiment, the illumination control device 120 calculates the illumination end time using, for example, a constant illumination intensity, and the first illumination control method disclosed above and shown in FIGS. 5, 8, and 9. It can be realized using. According to other embodiments, a plurality of A / D devices (such as 124) are not included and instead analog processing is performed.

Alternatively, according to another embodiment of the present invention, the lighting controller 120 uses, for example, the first lighting intensity I ₁ during the lighting sampling period and the main lighting period, as disclosed in detail above. We calculate the second light intensity I _N, realized by using the second illumination control method shown disclosed above in FIG 10A~10C it for. In such a case, the illumination intensity I ₁ (see FIGS. 10A-10C) used throughout the illumination sampling period 104 may be equal for all of the LED light sources 130A, 130B,. It is contemplated that the illumination intensity I _N used throughout (FIGS. 10A-10C) is equal for all of the LED light sources 130A, 130B,.

In accordance with another embodiment of the invention, each of the light sensing devices 122A, 122B,.
Can be used as separate light detection devices, and the calculations are performed using the individual amounts of light detected by each of the light detection devices 122A, 122B,... 122N, each or any combination of LED light sources 130A, At least one operation of 130B,..., 130N can be individually controlled. In this embodiment, the illumination control device 120 separately calculates the illumination end time for each of the LED light sources 130A, 130B,... 130N using a constant illumination intensity for each of the LED light sources 130A, 130B,. And can be implemented using the first lighting control method disclosed above and shown in FIGS. 5, 8, and 9. FIG. In this manner, a set of light sources 130A, 130B,... 130N (one set may include one) may be paired with a set of sensors 122A, 122B,.

Alternatively, according to another embodiment of the present invention, the lighting controller 120 uses the first lighting intensity I ₁ for the lighting sampling period and for the main lighting period, as disclosed in detail above. The second light intensity I _N can be calculated using the second illumination control method disclosed above and shown in FIGS. 10A to 10C. In such a case, the illumination intensity I ₁ may be equal for all of the LED light sources 130A, 130B,... 130N, and the illumination intensity I _N is equal for all of the LED light sources 130A, 130B,. It is possible.

  In general, this embodiment is suitable when the positioning of the light sources 130A, 130B,... 130N and the light detection devices 122A, 122B,. Signal from one or more light-sensing devices associated with one or more light sources in the control loop, ensuring that the “local control” of the signal is possible and that the crosstalk between the different light sources is at a sufficiently low level. Can be used when configured to allow moderate local control of the illumination intensity produced by one or more light sources 130A, 130B,... 130N.

  Reference is now made to FIG. FIG. 12 is a schematic diagram showing a front view of an autonomous imaging device having four photodetecting devices and four light sources according to one embodiment of the present invention.

  The device 150 includes four light sources 163A, 163B, 163C and 163D, and four light sensing devices 167A, 167B, 167C and 167D. Light sources 163A, 163B, 163C and 163D may be white LED light sources as disclosed above, or may be other suitable light sources. Photodetectors 167 A, 167 B, 167 C, and 167 D are mounted on the surface of baffle 70 that surrounds opening 62. The front portion of the device 150 may include four quadrants 170A, 170B, 170C and 170D. The device 150, as disclosed in detail above and shown in the drawings (see FIGS. 1 and 2), is a lighting control device (not shown in the front view of FIG. 12) and for image processing and transmission. All optical components, imaging components, electrical circuits, and power supplies can be included.

  The quadrant is schematically indicated by the areas 170A, 170B, 170C and 170D between the dotted lines. In accordance with one embodiment of the present invention, device 150 may include four independent local control loops. For example, the light source 163A and the light detection device 167A positioned in the quadrant 170A are in the same manner as the light sources 38A to 38N and the light detection device 42 are coupled to the illumination control device 40 of FIG. It can be coupled in an appropriate manner to a device (not shown). The signal from the light sensing device 167A can be used to control the illumination parameters of the light source 163A using any of the illumination control methods disclosed above, creating a local control loop for the quadrant 170A.

Similarly, the signal from the light sensing device 167B can be used to control the illumination parameters of the light source 163B using any of the illumination control methods disclosed above, creating a local control loop for the quadrant 170B. . Furthermore, the illumination parameter of the light source 163C can be controlled by using any illumination control method disclosed above by using the signal from the light detection device 167C, thereby forming a local control loop for the quadrant 170C. The signal from the light sensing device 167D can be used to control the illumination parameters of the light source 163D using any of the illumination control methods disclosed above, creating a local control loop for the quadrant 170D.

  Note that some crosstalk or interdependencies may exist between different local control loops. Because, in practice, some of the light generated by the light source 163A may be reflected from the intestinal wall or diffused by the intestinal wall, and other local controls for each of the other quadrants 170B, 170C, and 170D. This is because the light detection devices 167B, 167C, and 167D that form a part of the loop can be reached.

  The configuration of the positions of the light sensing devices 167A, 167B, 167C and 167D and the light sources 163A, 163B, 163C and 163D in the device 150 can be designed to reduce such crosstalk.

  In other embodiments of the invention, it may be possible to link the operations of different local control loops together using a processing method such as a “fuzzy logic” method or a neutral network implementation. In such an implementation, combining different local control loops together so that information from one of the light sensing devices can affect the control of the illumination intensity of the light sources in the other local control loops. Can do.

  Although the imaging device 150 shown in FIG. 12 includes four light sources and four light detection devices, the number of light sources may be changed, and a different number (greater than or less than four) of light sources Note that the imaging device of the embodiment of the invention can be constructed. Similarly, the number of light detection devices may be varied and any suitable or practical number of light detection devices may be used. In addition, it should be noted that the number of light sensing devices in the device need not necessarily match the number of light sources included in the device. Therefore, for example, a device having three light detection devices and six light sources can be configured. Alternatively, in another example, a device having 10 light detection devices and 9 light sources can be configured.

  Factors that determine the number of light sources and the number of light detection devices include, among other things, the geometrical (two-dimensional and three-dimensional) arrangement of light sources and light detection devices in the device, and the arrangement relative to each other, the light sources Size and available power, size and sensitivity of the light sensing device, and manufacturing and wiring considerations.

  The number of local control loops may also include, among other things, the degree of desired illumination uniformity, the degree of crosstalk between different local control loops, the processing power of available lighting controllers, and other manufacturing considerations. Can be determined by

  The inventor of the present invention can use one or more light sensitive pixels of the imager itself instead of or in addition to using a dedicated light detection device that is not part of the imager. Recognizing that it is possible to control lighting by using. In addition, special light sensing elements can be integrated into the pixel array on the surface of the CMOS imager IC.

  For example, in a CMOS type imager, some of the pixels of the CMOS imager can be used for illumination control, or alternatively, a specially manufactured light sensing element (in the imager pixel array ( An analog photodiode or the like).

Reference is now made to FIG. FIG. 13 is a top view that schematically illustrates pixel placement on the surface of a CMOS imager that can be used for illumination control, in accordance with one embodiment of the present invention. Note that the pixel arrangement of FIG. 13 is only a schematic diagram and the actual physical arrangement in the circuit on the imager is not shown.

  The surface of the CMOS imager 160 is schematically illustrated by a 12 × 12 array containing 144 square pixels. The regular pixel 160P is schematically indicated by a white square. The CMOS imager also includes 16 control pixels 160C, schematically indicated by a shaded square.

  The number of pixels in the CMOS imager 160 is arbitrarily selected as 144 for simplicity and clarity only, but more or less pixels may be used if desired. Please be careful. In general, a larger number of pixels can be used to provide a suitable image resolution. For example, a 256 × 256 pixel array may be appropriate for GI tube imaging.

  According to one embodiment of the present invention, the control pixel 160C may be a regular pixel of a CMOS imager assigned to operate as a control pixel. In accordance with the present invention, the control pixel 160C can be scanned at a different time than the regular imaging pixel 160P. This embodiment has the advantage that this embodiment can be implemented with a regular CMOS pixel array imager.

  Returning to FIG. 10A, according to one embodiment, the timing diagram of FIG. 10A can also be used here to illustrate an automatic illumination control method using control pixels. This method can be operated by using high-speed scanning of the control pixel 160C at the start of each imaging period 110. A lighting device (not shown) may be turned on (at time T2) at the start of the imaging period 110. The control pixel 160C can be scanned in the same manner as the regular pixel 160P, except that all control pixels 160C are scanned within the illumination sampling period 104. The control pixels 160C can be scanned sequentially within the duration of the illumination sampling period 104. This is possible due to the ability to randomly scan any desired pixel in the CMOS pixel array by addressing pixel readout lines (not shown) in an appropriate manner, as is known in the art. It becomes.

  Note that because the control pixels 160C are scanned sequentially (one after another), the first scanned control pixel is exposed for a shorter period than the next scanned control pixel. Thus, each control pixel is scanned after it has been exposed for a different exposure period.

  Assuming that the intensity of light reflected from the intestinal wall does not change significantly within the duration of the illumination sampling period 104, either the average light intensity measured for all of the control pixels 160C or all of the control pixels 160C. By correcting the calculated average amount of light that arrives by calculation, it may be possible to compensate for this incremental pixel exposure time. For example, a weighted average of pixel intensities can be calculated.

  Alternatively, according to another embodiment of the present invention, the lighting device 63 may be turned off after the end of the lighting sampling period 104 (this turn-off is not shown in FIG. 10A). This turn-off may allow scanning of the pixel 160C while the control pixel 160C is not exposed, thus preventing the incremental exposure of the control pixel as described above.

After all the control pixels 160C have been scanned (read out) and the signal values of the scanned control pixels have been processed (by analog or digital calculation or processing), the value of the illumination intensity required in the main lighting period Can be calculated, for example, by the lighting controller 40A (or, for example, the lighting controller 40 of FIG. 2).

The calculation of the required current or the required illumination intensity from the LED driver device 84 can be performed using the known value I ₁ (see FIG. 10B) as disclosed above, and the illumination device 63. May or may not take into account the duration of the period when is turned off (this duration is determined from the known time required to scan the control pixel 160C and of the data From the appropriate time required for processing and / or calculation, it can be determined in an appropriate manner). The illuminator 63 may then be turned on using the calculated current value (this turn-on is not shown in FIG. 10A for clarity) and the time at the end of the main illumination period 106 The illumination intensity value I ₂ (see FIG. 10B) required up to T _M is produced.

  Note that if the number of control pixels 160C is small, the time required to scan the control pixels 160C may be shorter than the total duration of the full illumination period 108. For example, if the scan time for scanning one control pixel is about 6 microseconds, about 96 microseconds may be required to scan 16 control pixels. Since the time required to calculate the required light intensity can also be shortened (a few microseconds or tens of microseconds can be required), the illuminator 63 at the end of the illumination sampling period 104 The period that is turned off may constitute a fraction of the main illumination period 108, which may generally be 20-30 milliseconds.

  It may also be possible to calculate a weighted average where the read intensity for each pixel may be weighted differently according to the position of a particular control pixel within the entire pixel array 160. Such weighting methods are known in the art, including, but not limited to, weights that are center-biased intensity weightings or include edge (or rim) weightings. It can be used to obtain any other type of biased measurement or any other suitable type of weighting known in the art. Such compensation or weighting calculations can be performed by any suitable process by an illumination control device (not shown) included in the imaging device or included in an imaging device including the CMOS imager 160 shown in FIG. This can be done by a device (not shown) or a control device (not shown).

Thus, if averaging or weighting calculations are used, after the control pixel readout and any type of compensation or weighting calculations are complete, the illumination controller (not shown) can detect the light detected by the control pixel 160C. The weighted (and / or compensated) quantity value can be calculated and this value can be used to calculate the value of I ₂ .

  Note that the ratio of the number of control pixels 160C to the regular pixels 160P should be a small number. The 16/144 ratio shown is given by way of example only (for clarity of explanation). In other implementations, this ratio may vary depending on, among other things, the total number of pixels in the imager's CMOS array and the number of control pixels used. For example, in a typical 256 × 256 CMOS pixel array, it may be practical to use 16 to 128 pixels as illumination control pixels for illumination control. However, the number of control pixels in a 256 × 256 CMOS pixel array may be less than 16 control pixels or greater than 128 control pixels.

  In general, the number of control pixels and the ratio of control pixels to regular pixels is notably the total number of pixels available on the imager's pixel array, the pixel scan speed of a particular imager, and the time allocated for scanning. Depending on the number of control pixels that can actually be scanned within and the duration of the illumination sampling period.

An advantage of an embodiment using an automatic illumination control method in which some of the pixels of a pixel array of a CMOS imager (such as the example shown in FIG. 13) is used is a photosensitive sensor that can be placed outside the surface of the imager. In contrast to (for example, the light detection device 67 of FIG. 3), the control pixel 160C is also an imaging pixel disposed on the surface of the imager, so the amount of light reaching the surface of the imager is actually measured. It is to detect. This can be advantageous in particular because of the higher accuracy of light detection, and can eliminate the need to accurately place the light detection device at the optimal location in the optical system, in addition to the control pixel. May have signal to noise and temperature dependent characteristics similar to other (uncontrolled) pixels of the imager.

  Another advantage of using control pixels is that there is no need for an external light sensing device, which allows the imaging device cost to be reduced and the imaging device assembly to be simplified.

Note that in a CMOS imager, such as imager 160, according to one embodiment, scanning of control pixel 160C after illumination sampling period 104 does not reset the pixel. Therefore, the control pixel 160C continues to detect and integrate light during the main illumination period 106 and is scanned after time T _M along with all other regular pixels 160P of the imager 160. Thus, the captured image contains complete pixel information. This is because the control pixel 160C and the regular pixel 160P are exposed for the same duration. Accordingly, the image quality or resolution is not significantly affected by controlling the illumination using the control pixels 160C.

  It should be noted that although the arrangement of the control pixels 160C on the imager 160 is symmetric with respect to the center of the imager, other suitable arbitrary pixel arrangements may be used. The number and distribution of control pixels on the imager 160 may be changed or adapted depending on the type of averaging used and / or the type of image captured, for example.

  Furthermore, control pixels can be grouped into groups. These groups can be processed separately to allow local illumination control within the imager using multiple light sources that can be controlled separately.

  Reference is now made to FIG. FIG. 14 is a schematic top view of pixels of a CMOS imager showing an exemplary distribution of groups of control pixels suitable for use in local illumination control within an imaging device, according to one embodiment of the present invention. It is.

  The illustrated imager 170 is a 20 × 20 pixel array having 400 pixels. The control pixels are schematically represented by the shaded squares 170A, 170B, 170C and 170C, and the remaining imager pixels are schematically represented by the non-shaded square 170P. Four groups of control pixels are shown on the imager 170.

  The first group of pixels includes four control pixels 170A arranged in the upper left quadrant of the surface of the imager 170. The second group of pixels includes four control pixels 170B arranged in the upper right quadrant of the surface of the imager 170. The third group of pixels includes four control pixels 170C arranged in the lower right quadrant of the surface of the imager 170. The fourth group of pixels includes four control pixels 170D arranged in the upper left and lower quadrants of the surface of the imager 170.

When the imager 170 is arranged in an autonomous imaging device having a plurality of light sources (such as but not limited to the device 150 in FIG. 12), four groups of control pixels 170A, 170B, 170C, and 170D are included. Each can be scanned and processed as disclosed above to provide data for local control of the level of illumination reaching each of the four quadrants of the imager 170. Scan data for each pixel in each of the four groups can be processed to calculate a desired value of illumination intensity for each quadrant of the imager. The method for controlling illumination using a separate local control loop may be similar to any of the methods disclosed above with respect to device 150 of FIG. 12, but in device 150 the light sensing device is external to the imager. The image pickup device 170 is different in that the control pixel used for detection is a pixel of the image pickup device which is a part integrated with the image pickup device 170.

  The illumination control method using control pixels can be implemented using a closed loop method that stops illumination when the integrated sensor signal reaches a threshold level, as disclosed above, or As disclosed in, using the initial illumination intensity during the illumination sampling period and adapting or changing the illumination intensity (if necessary) according to the value calculated or calculated from the control pixel scan. obtain.

  Signals or data for a group of pixels (representing a change in pixels) is known by using an averaging or weighted average method for averaging centered or marginally, or known in the art It can be processed according to any other averaging or processing method. Using the processing results as disclosed above, a light source (for example, four light sources arranged in the imaging device in an arrangement similar to the arrangement of the four light sources 163A, 163B, 163C, and 163D in FIG. 12). Can be controlled.

  The number of control pixels and the distribution of control pixels on the surface of the imager, in particular, the desired type of averaging, the required number of local lighting control groups, the number and position of light sources available in the imager, available Those skilled in the art will recognize that the processing power available to a particular processor may vary depending on the power available, the speed of the lighting controller, and other design considerations.

  According to another embodiment of the present invention, the control pixel 160C of FIG. 13 may be a specially fabricated pixel that is configured differently than the regular pixel 160P. According to this embodiment, control pixel 160C can be made as an analog photodiode with a suitable readout or sampling circuit (not shown), as is known in the art. This implementation may use a specially made custom CMOS imager in which an analog photodiode acting as control pixel 160C can be read out simultaneously, which may be advantageous. This is because the reading or scanning time can be shortened compared to the time required for sequentially scanning the same number of control pixels realized in a regular CMOS pixel array having a uniform pixel configuration.

  When an analog photodiode or other known type of dedicated sensor is integrated into the CMOS pixel array of the imager, the area where the analog photodiode is located is not scanned with the pixels of the regular CMOS array, so capture Note that the rendered image has “missing” image pixels. Therefore, the image data has “missing pixels”. However, if the CMOS pixel array includes a small number of analog photodiodes or other dedicated control pixels, it is possible that the missing pixels will not significantly degrade the image quality. In addition, such dedicated analog photodiodes or other control pixels can be distributed within the pixel array and can be placed sufficiently far apart from each other, so the image quality depends on the pixels of the missing image. Only slightly affected.

  Illumination control methods have been disclosed for use in autonomous imaging devices such as the device 10A of FIG. 1, but these illumination control methods can be used for other in-vivo imaging devices having an imager and illumination device, such as an imaging sensor. Can be used with or without adaptation to an endoscope or catheter-like device having an array, or a device for performing in-vivo imaging that can be inserted through the operating path of the endoscope, etc. Please pay attention to.

  In addition, the illumination control method disclosed herein includes a still camera, including a suitable imager, such as a CMOS imager, and connected to the illumination source in a manner that includes or operates the illumination source. It can be used in a video camera.

  In addition, the use of control pixels implemented in a CMOS pixel array imager, using selected regular pixels as control pixels, or using specially fabricated control pixels such as analog photodiodes, within the camera Or can be applied to control the illumination of a flash device or another illumination device that can be external to the camera and connected to the camera in an operative manner.

  The advantages of using control pixels that are part of the camera's CMOS imager are particularly controllable, including simple construction and operation, weighted average and bias methods, as disclosed in detail above. It may include the ability to implement and use multiple averaging methods that are compatible in aspects and increase the accuracy of lighting control.

  In addition, particularly in cameras that operate under the condition that a light source that is included in the camera or connected to the camera in an operating manner is the only available illumination source (e.g., operating at the sea floor). Using a lighting control method disclosed above allows the use of a camera without a shutter, in cameras or cameras that are designed to monitor or monitor in normally dark and inaccessible areas. obtain. This can advantageously increase the reliability of such devices, reduce their costs, and simplify their construction and operation.

  In the embodiment of the invention disclosed above, the number and arrangement of control pixels was constant, but according to another different embodiment of the invention, the number and / or geometric configuration (arrangement) of control pixels is Note that it can be changed or controlled dynamically. For example, temporarily returning to FIG. 2, the light sensing device 42 may represent one or more control pixels of a CMOS pixel array, and the illumination controller 40 and / or controller / processor device 36 may be used in an image capture period. It can be configured to change the number of control pixels to be changed and / or to change the arrangement of control pixels on the pixel array of the imaging device 32.

  Such a change in the number and / or arrangement of control pixels can be achieved by changing the number and / or arrangement of pixels selected to be scanned as control pixels during the illumination sampling period 104 (FIG. 10A). This can be done in a non-limiting example. Such changes may allow the use of different averaging configurations and methods and may allow for different biasing methods for different imaging periods.

  In addition, by using a dynamically controllable control pixel configuration to achieve two or more illumination sampling periods within one imaging period, and for each of these two or more illumination sampling periods It may be possible to use different numbers or configurations of pixels.

  It may also be possible to remotely control the number and / or configuration of control pixels by instructions transmitted wirelessly to a telemetry device, eg, remote device 34 (FIG. 2), in which case the telemetry device is It can be configured as a transceiver device capable of transmitting data and receiving control data transmitted to the telemetry device by an external transmitter device (not shown in FIG. 2).

The embodiments disclosed above are based on the measurement and processing of the amount of light reaching a light sensing element (eg, the light sensing device 67 in FIG. 3, the light sensing device 42 in FIG. 2, or the control pixel 160C in FIG. 13, etc.). It should be noted that, although it is based on changing the light output from the lighting device (for example, the lighting device 63 in FIG. 3), another method may be used.

  According to some embodiments of the present invention, the gain and / or other parameters of the pixel amplifier of the imager (such as the imager 32 of FIG. 2) can be changed. The decision to change the parameter may be based on, for example, a measurement result of the amount of light reaching the light detection device (eg, light detection device 42 in FIG. 2, control pixel 160C in FIG. 13, etc.). In such an embodiment, the illuminator of the imaging device (eg, illuminator 63A of FIG. 3 or illuminator 38 of FIG. 2) has a constant illumination intensity or a variable illumination intensity over a certain period or variable period. Can be operated. Light that reaches the light sensing device or control pixel of the imaging device during a sampling period (such as part of an exposure period within one frame) can be measured at the sampling stage or time point. The sampling stage or time point may be a discontinuous time point in time, or may extend over a certain amount of time. Parameters, eg gain level or sensitivity of the imager pixel amplifier, light intensity, illumination duration, or other parameters, eg individually or in any combination with respect to the relative light saturation measurement of the selected pixel It is possible to perform appropriate or appropriate imaging by changing the mode.

  For example, the amount of light that reaches the light sensing device during the illumination sampling period, measured in at least one selected sampling stage (period), is referenced to an expected threshold value (eg, for a defined number of pixels). The exposure can be terminated when it is nearly sufficient to ensure proper exposure of the image. In this case, since complete exposure has been obtained, no further exposure is required. In this case, it should not be necessary to change the current gain level of the image when transmitting the image. In addition, since the exposure is relatively short, there should be no haze problems that can accompany images recorded using long exposures.

  If the measurement at the sampling stage determines that too little saturation could be achieved (based on the threshold) during the illumination sampling period, exposure can continue to allow sufficient illumination of the image Should be. However, overexposure can cause haze, so the imager can be commanded to lower the saturation threshold and perform a shorter exposure. In order to compensate for short exposures, in addition to lowering the saturation threshold, the imager is commanded to provide a higher gain level for image transmission, providing adequate exposure even with short exposure times. Can be done. For example, if the saturation threshold is halved and the exposure is short enough, the gain level must be doubled accordingly to ensure that proper exposure can be performed.

  If too much light reaches the light detector during the illumination sampling period, possibly with reference to the expected threshold, the exposure can be terminated and the pixel amplifier gain (or other Parameter) can be reduced to prevent overexposure. Additional sampling periods can be set at selected stages to further fine tune variables such as image gain and exposure time.

  In addition to changing the analog gain that can be based on continuously scanning the analog output of a selected number of pixels in the initial aspects of the exposure period, the exposure is at any stage that reaches full (eg, proper) saturation. Can be terminated. In this way, for example, adding a gain level to the image can provide full exposure of the image in many cases of low exposure. In addition, overexposure can be prevented in many cases of high exposure, for example by terminating exposure when saturation is obtained. These changes can result in improved image quality, energy savings, and / or other benefits.

  Various embodiments can use various time, saturation, and voltage levels and are not limited to the following defined levels. According to a particular application of the invention, the required time resolution defining the maximum readout time required to achieve saturation for all preselected pixels is, for example, 0.25 s. obtain. Other values or ranges may be used.

In accordance with some embodiments of the present invention, a total exposure time (eg, an estimated time required for proper and / or proper exposure) can be defined (T1), within which time the exposure measurement time ( A sampling time, eg, T1 / ₄ or some other time that is part of T1, can be defined. A discrete time step in which a change in the reference level can occur and a gain determination can be made can be determined by T1. This value can be used indirectly to set time intervals such as T1 / ₂ and T1 / ₄ , or other intervals, which can be sampling time intervals to measure pixel saturation. A maximum exposure time can also be defined (T _M ). In general, both T1 and T _M are programmable. In general, T _M does not affect the computation other than setting the maximum exposure time that can be terminated exposed regardless of whether exceeds the threshold of exposure. On the other hand, T1 can be used as a target exposure time. For example, T1 can be referred to as the expected exposure to obtain proper or complete saturation and the like. A current system or method according to some embodiments sets a saturation threshold level that is expected to exceed before T1, for example at intervals T1 / ₄ and T1 / ₂ .

  In general, the device 30 transmits image information as a discontinuous portion. Each part generally corresponds to one image or frame. Other transmission methods are possible. For example, the device 30 can capture an image once every half second, and after capturing such an image, it transmits this image to the receiving antenna. Other capture rates are possible. Generally, the image data to be recorded and transmitted is digital color image data, but other image formats (such as black and white image data) may be used in alternative embodiments. In one embodiment, each frame of image data includes 256 rows of 256 pixels each, and each pixel includes data relating to color and brightness according to known methods. For example, at each pixel, the color may be represented by a mosaic of four sub-pixels (one primary color is represented twice), each corresponding to a primary color such as red, green, or blue. The luminance of the entire pixel can be recorded with a luminance value of 1 byte (that is, 0 to 255), for example. Other data formats may be used.

  According to one embodiment, reliable exposure measurements may require that every nth (eg, 4th) pixel is included (this pixel is considered to be every 2nd red pixel, for example). Because, according to one embodiment, there are typically more red pixels for every m rows (eg, typically 10 rows out of 256 rows in about 66,000 pixel frames (such as 256 × 256 pixels)). To do that). This is equivalent to about 640 pixels in a typical frame. In one example, reliable exposure measurements exceed the saturation threshold, so about 1.5% of the selected pixels (eg, 11 out of 640 pixels, etc.) reach saturation. This may be necessary, and the gain may be determined according to the saturation threshold. Other frame sizes, ratios, and sampling rates may be used as appropriate. For example, 9, 11, 15, 24, and any other number of pixels can be used per frame or per sampled subset to determine the saturation threshold. Other individual pixels, such as non-red pixels, may be sampled and the sampling need not be based on color.

According to one embodiment, the exposure time can be determined in 8 steps, for example from 5 ms to 40 ms. Other numbers of steps and intervals may be used and intervals may not be used. That is, for example, the exposure time can be determined continuously. Furthermore, T1 can be digitally programmed in 8 steps, for example with a logarithmic scale from 1 ms to 100 ms. In one example, the accuracy of the detection level may be defined as less than 5%, for example. Other accuracy levels may be used as appropriate.

Exposure measurements according to one embodiment can be performed on a subset of pixels in a sensor array or imager. The determination as to whether the change in exposure gain is appropriate is based on, for example, the percentage of pixels that are saturated with light and selected with respect to the saturation threshold for one or more pixels. It is possible. The decision to set the gain or other parameter may be based on one or more discrete time intervals. Within this time interval, the output from a nominal number of selected pixels (eg, 11 according to one embodiment) reaches a certain saturation level (such as a reference level) or threshold. To do. In this way, exposure can continue until it is determined that the pixel output from the nominal number of pixels has reached a new saturation level, at which point the gain (or other parameter) is reached. ) Level can be changed. According to one embodiment, for example, exposure can continue until full saturation or maximum exposure time (T _m ) is reached. Note that the determination of full saturation can vary depending on the level of various gains (or other parameters). For example, the saturation expected at gain 1 may be V1, and the saturation expected at gain 4 may be V1 / ₄ . The reference voltage (Vref) or threshold voltage for determining whether to change the gain and / or exposure can be defined at any non-contiguous time interval based on the ratio of time to T1. . For example, Vref can be considered to be equal to Vfs / ₄ at time T1 / ₄ when light reflection can first be measured. Similarly, Vref can be considered equal to Vfs / ₂ at time T1 / ₂ when light reflection can be measured thereafter.

  According to some embodiments of the present invention, the overall gray scale for a selected pixel (eg, 640 in the current example) can be measured at one or more intervals. This average value can be compared to a saturation threshold, and the gain determination made can be related to the average of the grayscale measurements and the associated saturation threshold.

According to some embodiments of the present invention, the signal saturation level can be defined as voltage saturation representing low pixel voltage or Vsat, and can be defined as pixel saturation referred to as ground. The pixel reset level may be defined as Vrst representing the highest pixel voltage. Finally, Vfs can be defined as an A / D full-scale voltage that represents the actual saturation or voltage level at defined intervals. Therefore, Vsat = Vrst−Vsat = Vfs. That is, the pixel signal level can be defined as the difference between the pixel reset level and the instantaneous pixel voltage, and can be a positive voltage that increases from zero during exposure. This “delta voltage” can be compared to a reference voltage of a comparator such as, for example, Vfs / _{4 at} T1 / ₄ .

  Reference is now made to FIG. FIG. 15 illustrates a gain setting determination that may be made as a function of pixel output (light saturation) versus time during an exposure period, according to one embodiment of the present invention. As can be seen in FIG. 15, the three gain settings that can be used are gain 1, gain 2, and gain 4. The thicker lines 161, 163 and 165 represent gain limits or thresholds. The set values in FIG. 15 are presented as examples only and are not intended to be limiting. Other numbers of gain settings may be used.

At intervals such as T1 / ₄ , the saturation threshold (level) for the selected pixel can be measured. It is conceivable that the saturation threshold is equal to, below, or above the expected threshold 161. If the output of the pixel (average saturation of the selected pixel) is “b” above the expected threshold 161, it can be predicted that complete exposure will be completed, for example, within T1. Therefore, there is no need to increase gain or sensitivity, and exposure is continued until full saturation (Vfs) is reached, and exposure is terminated when full saturation is reached.

If the output of the pixel is less than the expected threshold value 161 but “c” exceeds the intermediate threshold value 163, it can be predicted that the exposure will not be completed within T1. Even though saturation can be obtained as a result, the exposure will necessarily be longer than T1, which may cause a hazy effect. Therefore, a command can be given to the imager to increase the gain level from gain 1 to gain 2. Thus, the saturation threshold can be reduced, for example, by half to Vfs / ₂ , and this Vfs / ₂ and, for example, gain 2 amplification, can provide full exposure of the image. Next, this exposure can be continued until it reaches the saturation level Vfs / _2, it is possible to terminate the exposure when it reaches the saturation level Vfs / _2. Vfs / ₂ represents complete saturation in this case. This is because gain level 2 is applied. Other gain levels may be used.

If the pixel output is less than the intermediate threshold 163 but is “d” above the lower threshold 165, it can be predicted that the exposure will not be completed within T1. Therefore, in addition to continuing exposure, it is considered necessary to further increase the gain level. Gain level can give the example command to the imager to increase to gain 4, the corresponding exposure can then be continued until it reaches the saturation level Vfs / _4, reaches the corresponding saturation level Vfs / ₄ The exposure can be terminated at that point.

If the pixel output is “a”, which is less than the lower threshold 164, it can be predicted that the exposure will not be completed within T1, or even within T _M. Thus, for example, it may be necessary to increase the gain level to gain 4, and exposure may continue until T1. In this example, since complete exposure cannot be achieved even at T1, the exposure can be continued up to T _M to increase the possibility of obtaining sufficient exposure. T _M can be the maximum exposure time in either case.

  In the above example and as can be appreciated with respect to FIG. 15, full exposure is achieved in 3 of the 4 frames, and the exposure time is similarly reduced in 3 of the 4 frames. Potentially resulting in a significant increase in the sharpness of the exposure and a decrease in the use of the power supply. In alternative embodiments, other levels of changes or improvements may occur.

It is also possible to provide further measurement stages, such as T1 / ₂ and T1 / ₃ . The pixel exposure in the above scenario can also be measured at this second interval to reveal whether further gain level changes are needed.

  In one embodiment, the first scan can be used to look for “white spots” or “hot spots”. These spots are problematic (poor quality or nonfunctional) image receivers that cannot be counted in groups of pixels that have reached saturation. Thus, this initial scan can be designed to detect, define, and discard problematic or non-functional pixels from a selected group of pixels. Such scanning of defective pixels / non-functioning pixels may not be used.

  The following is an example of a non-limiting description of “pseudocode” that can be used to implement an embodiment of the present invention. Other embodiments of the invention can be implemented without coding such as using circuit design. Various embodiments of the invention may be implemented using various code sequences and programming or logic design techniques.

  Note that in some cases, such automatic gain control can cause changes in the signal-to-noise ratio (S / N) of the imager under certain conditions. For example, increasing the gain of a pixel amplifier in a CMOS pixel array imager can result in a higher signal-to-noise ratio and increasing the “haze” of the image by extending the exposure time (Tm).

  According to some embodiments of the invention, the principles described above and in connection with FIG. 15 are used here as well, for other parameters such as illumination intensity and duty cycle, or combinations of such other parameters. An implementation example of the present invention can be described. For example, depending on the threshold at a selected stage, a method for determining light saturation related to light intensity, duty cycle, etc. can be followed. These calculations of the saturation level can determine whether such a parameter is at a predetermined threshold, below a predetermined threshold, or above. With such a determination, it is possible to make a determination regarding changes in the illumination of light, duty cycle, etc., and reflect the necessity of exposure of the frame.

  For example, a controller or any other element can measure the light saturation level at one or more light measurement elements, and in response to the resulting measurements, the duration of illumination, illumination intensity, And / or at least one of the gain levels of the image can be controlled simultaneously. According to one embodiment of the present invention, the illumination (exposure) can be increased by a factor of eight, for example, using the following or other probabilities.

  Any other combination of parameters that may be needed to achieve the above or alternative lighting target values may be used. In addition, any other suitable parameters can be incorporated into the above-described embodiments individually or in any combination to allow high precision exposure by the in-vivo imaging device.

  In accordance with some embodiments of the present invention, a method is provided for determining the location or position of an in-vivo device, such as an in-vivo imaging capsule. For example, a method is provided for determining when an in-vivo device has entered the body, when it has entered a specific region within the body, or the like. This determination can be used, for example, to determine whether the in vivo capsule should enter or exit an operating mode such as “high speed mode”, “low speed mode”, or “standard mode”. For example, the high speed mode allows the imaging device to achieve a higher frame rate, which is believed to be particularly useful in that it allows high speed imaging of the esophagus after swallowing the imaging capsule. However, such high speed imaging is not required when the device is, for example, in the small intestine, and therefore the device can be programmed to switch to “standard mode” after a period of time after the device is internalized. . Other operating mode changes may be made. Thus, for example, an imaging device transmits compressed data in “fast mode” when descending the esophagus and then in normal uncompressed mode at a lower frame rate if such a fast frame rate is not required. Can be operated.

  In one embodiment of the invention, this can be done by setting a mode, such as high speed mode, to end when a significant change in the environment surrounding the device is observed. This can be done by providing environmental monitoring tools, such as a pH indicator, temperature gauge, or light level indicator, inside or outside the imaging device to measure or calculate environmental data. A monitoring or measuring tool can compare the measured data with previously measured environmental data to determine environmental changes. For example, when the capsule environment drops below a certain pH level, this change in pH level may indicate that the imaging device has entered the stomach through the esophagus. Various environmental changes may be sought, depending on the measurement tool used, eg, the measurement tool used outside the body, in the body, in the oral cavity, in the pharynx, in the esophagus, in the stomach, in the small intestine, etc.

In other examples, a mode such as fast mode may be set to end after a certain amount of time after a change is detected, eg, 5 minutes. The change may be, for example, that the capsule has entered a dark environment such as the oral cavity. For example, the controller can set the light source to provide “dark frames” at a defined frame interval, such as one frame every 256 frames. During a dark frame, an LED or other illumination source may or may not light for a short time, but is substantially unsuitable for providing a functional exposure to the image. For example, an in-vivo imaging device may require an exposure of 25 ms at a constant illumination intensity to properly illuminate the lumen, but dares to perform an inappropriate exposure of 5 ms, for example. The device can periodically process “dark” frames, which can be analyzed to determine whether ambient light is present in the environment of the device. If the ambient light is above the threshold level, indicating that there is a significant amount of ambient light and that the image does not require much more light to obtain saturation, the capsule It can be assumed that the patient has not yet entered the body and should continue in high speed mode. The capsule has entered a darker environment, such as the body, when the ambient light in a dark frame is below the threshold level, indicating that the image needs a significant amount of light to achieve saturation Can be assumed. In this case, it can be assumed that the fast mode is no longer necessary after a predetermined period, for example 5 minutes. It can be assumed that the capsule passes through the esophagus within this predetermined time.

  According to some embodiments, the exposure of the dark frame is measured with respect to the light saturation threshold for the dark frame, and a change in the gain level of the imager is required and / or how much the gain level of the imager is changed Can be determined. A dark frame requires a substantially non-maximum gain factor, and the image has a relatively adequate amount of light and only requires a relatively small gain level to reach full exposure. If indicated that this can be done, the device may be defined as being external. If a dark frame requires a large gain factor or maximum gain factor and is shown to require significant gain to be able to reach full saturation, the device can be defined as being in the body.

  FIG. 16A illustrates a series of steps of a method for determining the required image gain level during an exposure period according to one embodiment of the present invention. In alternative embodiments, other steps and other series of steps may be used.

  In step 500, a device such as an in-vivo imaging device turns on the light source.

  In step 510, which may be a short sampling period, the apparatus records (and possibly integrates) the amount of light received by the at least one light measuring element. This could be for example for a sensor on the device or possibly an external sensor.

  In step 520, the device determines the amount of light recorded.

  In step 530, for example, if the amount of light recorded by some of the pixels of the frame is less than a certain predetermined value (saturation threshold).

  In step 540, the gain level of the image can be increased and the device can continue exposure (or other parameters such as light level) until saturation is reached at 560. In this case, step 520 may be repeated at subsequent time intervals.

  If the amount of recorded light is greater than a certain value (threshold), the gain level of the image can be lowered at step 550. Step 520 may be repeated at a later time. At full saturation, the exposure can be terminated at 560.

If the amount of light recorded is substantially equal to a predetermined saturation threshold (the value is close to such a threshold, so that the exposure can be considered sufficient), the current Such as gain level or light level at the same time, and when full saturation occurs or the maximum exposure time (T _M ) is reached regardless of which of these occurs first Can be terminated. This process may then be repeated at 570 over subsequent frames.

  In step 570, the process described above is repeated from step 500. This is because the device can operate over a series of imaging periods. However, this method need not be repeated.

  According to one embodiment, steps 500 through 520 analyze the data from the environmental monitoring tool so that one or more specific data measurements, eg, pH level, temperature level, etc., determine a threshold for the specific measurement. It can be supplemented or replaced by determining whether it is above, below or equal to, or above, below, or equal to one or more previous measurements. The result of such a comparison can be used to determine whether an environmental change has occurred and whether an appropriate gain level change is appropriate. For example, an in vivo capsule can be adapted to carry a plurality of measurement tools for measuring different aspects in the environment. These measurement tools include a light level indicator and a pH indicator. The capsule can measure levels i and ii in frame A using the two indicators described above. In the second frame B, for example, it can be determined that both parameters i and ii have changed substantially from their measurements in frame 1. If the light level indicator reflects the darkness of the environment and the pH indicator shows a higher acidity, the capsule enters the body (in a darker environment) and enters the stomach (acidity) Rise).

  FIG. 16B illustrates a series of steps of a method for determining when an in-vivo device has entered an area having different illumination, according to one embodiment of the present invention. In alternative embodiments, other steps and other series of steps may be used.

  In step 600, a device such as an in-vivo imaging device turns on (activates) the light source.

  In step 610, the device records (and possibly integrates) the amount of light received by the light measuring element. This could be for example part of the imager, a sensor on the device, or possibly an external sensor.

  In step 620, the device determines the amount of light recorded. In addition, the device can calculate the amount of light recorded with respect to the saturation threshold or any other threshold and determine the possible position of the device based on the amount of light recorded. For example, if the light recorded in the first frame is above the saturation threshold of, for example, 15 pixels in this frame, this indicates that saturation was easily obtained, and the device Is assumed to be outside the body (bright environment). If the light recorded in the second frame is below the same saturation threshold, for example 15 pixels of that frame, this indicates that saturation has not been reached and the device It is assumed that it is in a (dark environment).

  At step 630, a decision can be made to change the operating mode of the device depending on the amount of light recorded with respect to the threshold.

  In step 640, for example, if the amount of light recorded does not reach a certain value (threshold), indicating that the device is located in a darker area, the device is in 640 operating mode. Can be changed to reflect this darker environment. For example, the device may be set to begin operating in high speed mode for a period of 10 minutes after entering the body, allowing high speed imaging of esophageal areas. After it is determined that the device has entered the body, a timer can be started so that after 10 minutes, the device changes to the slow mode for the remainder of the process.

  If in step 650, for example, the amount of recorded light is greater than a certain value (threshold), indicating that the device is located in a brighter area, the device sets the operating mode at 650. Can be changed to reflect this brighter environment.

  FIG. 16C illustrates a series of steps of a method for determining the position of an in-vivo device according to one embodiment of the present invention. In alternative embodiments, other steps and other series of steps may be used.

  In step 700, a device such as an in-vivo imaging device activates at least one environmental measurement device such as a pH level sensor and a light detection meter.

  In step 710, the device records measurements such as the pH level received by the measuring device. This measuring device may be, for example, a sensor on the device or a sensor in the device and / or an external sensor.

  In step 720, the device determines the quantity and / or quality of the recorded measurement.

  In step 730, the device may determine a position within the body based on the recorded measurement data, such as compared to a threshold or previous measurement. For example, if the pH level in the first frame exceeds a saturation threshold of, for example, 7 on the pH scale, this means that the device is in a non-acidic environment and that the pharyngeal region (acid-medium Can be assumed to exist within the sex environment). If the pH level recorded in the second frame is below the same threshold on the pH scale, e.g. 7, this means that the device is in a more acidic environment and recorded Indicates that it can be assumed to be present in the region of the stomach or small intestine depending on the pH level.

  At step 740, a decision may be made to change the operating mode of the device, depending on the recorded measurement data for a threshold or alternative value.

  In step 750, for example, the amount and / or quality of the measurement data is above or below a certain value (threshold or other value) and the device is located in a different region. If shown (or verified), the device can change its operating mode to reflect this new environment.

  The results of the above process can be used to determine whether the environmental conditions have changed substantially based on results from a variety of optional monitoring and / or measurement tools. Changes that must be defined as “substantially” or “significantly” can be determined on a case-by-case basis or on a production basis.

In general, the various embodiments discussed in this specification may be implemented in a device such as device 30 (FIG. 2). However, such an embodiment may be realized by various imaging devices or detection devices having different structures. Processing, monitoring, measurement, analysis, definition, tracking, comparison, calculation, command, stop exposure, increase gain, decrease gain, increase exposure, decrease exposure, mode change, etc. The various functions and processes described above may be performed by a processor unit (such as 36 in FIG. 2). These functions or processes may be performed by the processor device 36 alone or by alternative devices such as the lighting control device 40, telemetry device 34, light sensing device 42, imaging device 32, or any combination of these devices. Additionally and / or alternatively can be implemented. The methods and processes described herein can also be implemented with other sensing devices having other structures and other components. Alternatively, some or all of the analysis or control involved in the various methods presented can be performed at an external workstation or processing device.

  Although the invention has been described with respect to a limited number of embodiments, many modifications, variations, combinations, and other applications of the invention may be made and are within the spirit and scope of the invention. Those skilled in the art will recognize that.

It is the schematic which shows one Example of the autonomous type in-vivo imaging device of a prior art. It is a schematic block diagram which shows a part of in-vivo imaging device which has an automatic illumination control system according to one Example of this invention. 1 is a schematic cross-sectional view of a portion of an in-vivo imaging device having an automatic illumination control system and four light sources according to one embodiment of the present invention. FIG. 4 is a schematic front view of the apparatus shown in FIG. 3. FIG. 3 is a schematic diagram illustrating a method for timing illumination and image capture in an in-vivo imaging device having a constant illumination duration according to one embodiment of the present invention. FIG. 3 is a schematic diagram illustrating one possible configuration for a light control device coupled to a light sensing photodiode and a light emitting diode, in accordance with one embodiment of the present invention. FIG. 7 is a schematic diagram illustrating in detail the illumination control device of FIG. 6 according to one embodiment of the present invention. FIG. 2 is a schematic diagram useful for understanding a method of timing illumination and image capture in an in-vivo imaging device having a variable controlled illumination duration according to one embodiment of the present invention. FIG. 2 is a schematic diagram useful for understanding how to time illumination and image capture in an in-vivo imaging device with variable frame rate and variable controlled illumination duration according to one embodiment of the present invention. . It is a timing diagram which shows roughly the imaging period of the in-vivo imaging device using the automatic illumination control method according to another one Example of this invention. FIG. 10B is an exemplary and schematic graph showing light intensity as a function of time, for example possible using the automatic lighting control method shown in FIG. 10A, according to one embodiment of the present invention. FIG. 10B is another exemplary and schematic graph illustrating another example of light intensity as a function of time possible using the automatic lighting control method shown in FIG. 10A, in accordance with one embodiment of the present invention. It is the schematic which shows the illumination control apparatus containing the several photon detection apparatus for controlling several light sources according to one Example of this invention. It is the schematic which shows the front view of the autonomous type imaging device which has four light detection apparatuses and four light sources according to one Example of this invention. FIG. 3 is a schematic top view showing the arrangement of pixels on the surface of a CMOS imager that can be used for illumination control according to one embodiment of the present invention. FIG. 3 is a schematic top view of pixels of a CMOS imager showing an exemplary distribution of groups of control pixels suitable for use in local illumination control in an imaging device, in accordance with one embodiment of the present invention. 4 is an exemplary schematic graph representing light saturation as a function of pixel output and time, possibly when performing light control, in accordance with one embodiment of the present invention. FIG. 4 shows a sequence of steps of a method according to an embodiment of the method. FIG. 4 shows a sequence of steps of a method according to an alternative embodiment of the invention. FIG. 6 shows a sequence of steps of a method according to yet another embodiment of the invention.

Claims (80)

An in-vivo imaging device,
At least one light source;
At least one imager;
At least one controller, wherein the controller is configured to activate the light source, record the amount of light reflected by the imaging device, and control the gain level of the image of the imager during the imaging period In vivo imaging device.   The apparatus of claim 1, comprising at least one light measurement element.   The apparatus of claim 2, wherein the at least one light measurement element includes at least a portion of a set of pixels.   The apparatus of claim 2, wherein the at least one light measurement element includes at least one photodetector.   The apparatus of claim 2, wherein the at least one light measurement element is integrated with the imager.   The imaging device of claim 1, wherein the controller is adapted to control at least one parameter selected from the group consisting of an image gain level, illumination duration, and illumination intensity.   The imaging device of claim 1, wherein the controller is adapted to control at least one parameter selected from the group consisting of illumination duration and illumination intensity for at least one of a plurality of light sources.   8. The imaging device according to claim 7, wherein the individual control of the parameter is enabled by at least one control pixel for at least each one of a plurality of light sources.   The imaging device of claim 8, wherein the control pixels are adapted to allow a fast readout procedure.   When the amount of light recorded at the time of sampling is below a defined saturation threshold, the controller is from the group consisting of increasing the gain level of the image, reducing the duration of illumination, and increasing the illumination intensity. The imaging device of claim 1, adapted to perform at least one of the selected functions.   The apparatus of claim 1, comprising a transmitter.   The apparatus of claim 1, comprising at least one measurement tool.   The apparatus of claim 12, wherein the at least one measurement tool is adapted to measure at least one environmental parameter selected from the group consisting of a light level and a pH level.   The apparatus of claim 12, wherein the measurement tool is present at a location selected from the group consisting of an interior of the apparatus, a surface of the apparatus, and an exterior of the apparatus.   The device of claim 1, wherein the device is a swallowable capsule. An in-vivo imaging device,
At least one light source;
At least one light measuring element;
At least one imager;
At least one controller, wherein the controller is configured to activate the light source, record the amount of light reflected by the light measurement element, and control the gain level of the image of the imager during the imaging period. In vivo imaging device. An in-vivo imaging device,
At least one illumination means for providing illumination to the device;
At least one imager means for recording an image for the device;
In-vivo imaging device comprising at least one controller means for controlling the gain level of the image of the imager. A method for operating an in-vivo imaging device including at least one light source comprising:
Activating at least one light source during an imaging period;
Recording the amount of light reflected by the at least one light measuring element in the sampling phase;
Comparing the amount of light recorded in at least one sampling stage within the imaging period with a predetermined light saturation threshold;
Controlling the gain factor of the imaging device with respect to the difference between the recorded amount of light and the light saturation threshold.   The method of claim 18, comprising controlling the operation of a light source with respect to a difference between the recorded amount of light and the light saturation threshold.   The method of claim 18, comprising controlling the operation of each of at least one light source of the plurality of light sources.   The method includes at least one function selected from the group consisting of controlling the intensity of the light source and controlling the duration of operation of the light source with respect to a difference between the amount of recorded light and the light saturation threshold. 18. The method according to 18.   The method of claim 18, wherein the operation of the light source is stopped when the amount of recorded light exceeds a defined light saturation threshold.   The method of claim 18, wherein the gain factor is decreased when the amount of recorded light exceeds the defined light saturation threshold.   19. The method of claim 18, wherein the gain factor is increased when the recorded amount of light is less than the defined light saturation threshold.   19. The method of claim 18, wherein if the received light is substantially equal to the light saturation threshold, exposure is continued with a constant gain factor until full saturation is obtained. At least in the second sampling stage,
Comparing the amount of recorded light with a defined light saturation threshold;
The method of claim 18, comprising controlling a gain factor of an imaging device with respect to a difference between the amount of recorded light and the light saturation threshold at the second selected interval.   27. The method of claim 26, comprising controlling the operation of the light source with respect to a difference between the recorded amount of light and the light saturation threshold.   27. The method of claim 26, comprising controlling the effect of the light source intensity on the difference between the recorded amount of light and the light saturation threshold.   The method of claim 18, wherein the light measurement element comprises at least a portion of a set of pixels disposed within an imager disposed within an in-vivo device.   The method of claim 18, wherein the light measuring element comprises a photodetector and the device comprises an imager.   The method of claim 18, wherein the step of recording the amount of reflected light is recorded from a portion of a frame's pixels.   27. The method of claim 26, wherein the light saturation threshold is defined when a selected number of pixels from the portion of pixels has reached saturation.   33. The method of claim 32, wherein substantially half of the portion of pixels is a red pixel.   35. The method of claim 32, comprising calculating a gain factor based on how many of the selected number of pixels have reached saturation in at least one sampling stage.   35. The method of claim 34, comprising changing the operation of a light source with respect to the calculated gain factor.   36. The method of claim 35, wherein the step of changing a light source comprises at least one function selected from the group consisting of changing the duration of illumination and changing the illumination intensity for at least each one of the light sources.   24. The method of claim 23, wherein the reduction of the gain factor reduces a signal to noise disturbance factor.   25. The method of claim 24, wherein the increase in gain factor increases a signal to noise disturbance factor.   19. The method of claim 18, comprising detecting a non-functional pixel in the light measurement element and marking the non-functional pixel as unusable.   The method of claim 18, wherein the device is a swallowable capsule. A method for operating a biological imaging device including at least one light source comprising:
Activating at least one light source during an imaging period;
Recording the amount of light reflected by the at least one light measuring element in the sampling phase;
Comparing the amount of light recorded in at least one sampling stage within the imaging period with a predetermined light saturation threshold;
The difference between the amount of recorded light and the light saturation threshold is selected from the group consisting of controlling the intensity of the light source, controlling the duration of operation of the light source, and controlling the gain factor of the imaging device. Controlling at least one function. An in-vivo imaging device,
At least one light source;
At least one imager;
An in-vivo imaging device comprising: at least one controller, wherein the controller is configured to detect problematic pixels in the imager and to define the problematic pixels as non-functional.   43. The apparatus of claim 42, wherein the imager is configured to provide a duration of exposure that is less than a duration generally required for functional pixel saturation.   43. The apparatus of claim 42, wherein the controller detects at least one pixel that reflects a saturation level that is above a threshold saturation level. An in-vivo imaging device,
At least one light source;
At least one imager configured to provide a shorter duration exposure than is typically required for functional pixel saturation;
A controller, wherein the controller is configured to detect a problematic pixel in the imager based on the short duration and to define the problematic pixel as non-functional Imaging device. An in-vivo imaging device,
At least one lighting element for providing illumination to the device;
At least one imager element for recording an image for the device;
An in-vivo imaging device comprising: at least one controller element for detecting problematic pixels in the imager and defining the problematic pixels as non-functional. A method for detecting problematic pixels in an imaging device,
Initiating exposure for a duration shorter than that required for general saturation of at least one functional pixel;
Detecting at least one pixel reflecting a saturation level above a threshold saturation level;
Defining the at least one pixel reflecting a saturation level above the threshold saturation level as non-functional.   48. The method of claim 47, comprising mapping the non-functional pixel.   49. The method of claim 48, comprising excluding the non-functional pixel from a future saturation level determination process.   48. The method of claim 47, wherein the imaging device is contained within a swallowable capsule. A method for detecting problematic pixels in an imaging device,
Initiating a shorter duration exposure than that required for functioning pixel saturation; and
Detecting at least one pixel reflecting a saturation level above a threshold saturation level;
Defining the at least one pixel reflecting a saturation level above the threshold saturation level as non-functional;
Excluding said non-functional pixel from a saturation level determination process to be performed in the future. An in-vivo imaging device,
At least one light source;
At least one imager;
At least one controller, wherein the controller activates the light source to provide a dark frame at a defined frame interval and to record the amount of light reflected to the imager during the dark frame. In-vivo imaging device adapted.   53. The imaging device of claim 52, wherein the dark frame includes a frame in which a substantially inappropriate amount of light is exposed by the light source.   53. The imaging device according to claim 52, wherein the controller can determine a position of the device according to the amount of the light reflected by the imaging device during the dark frame.   55. The imaging device of claim 54, wherein the location of the device is determined to be at least one environment selected from the group consisting of extracorporeal, intracorporeal, intraoral, intrapharyngeal, esophageal, and intragastric.   53. The imaging device of claim 52, wherein the controller is configured to change an operation mode of the device with respect to the amount of light. An in-vivo imaging device,
At least one light source;
At least one imager;
At least one controller, wherein the controller activates the light source to provide a dark frame at a defined frame interval and to record the amount of light reflected to the imager during the dark frame. And an in-vivo imaging device adapted to change an operating mode of the imaging device with respect to the amount of recorded light. An in-vivo imaging device,
At least one illumination means for providing illumination to the device;
At least one imager means for recording an image for the device;
Activating the illumination means to provide a dark frame at defined frame intervals, recording the amount of light reflected to the imager means during the dark frame, and further reflecting to the imager means during the dark frame An in-vivo imaging device comprising: at least one controller means for determining the position of the device in accordance with the amount of light emitted. A method for determining when an in-vivo device has entered the body,
Configuring dark frames at selected frame intervals in the device imager device;
Performing a substantially inappropriate exposure with at least one light source in each of the dark frames;
Measuring exposure of the image reflected during the dark frame as a function of light saturation threshold;
Defining the device as outside the body when the dark frame requires a substantially small amount of light to reach saturation.   60. The method of claim 59, wherein the device is defined as being outside the body when the dark frame requires a substantial amount of light.   61. The method of claim 60, comprising changing the mode of operation of the device at defined time intervals after the device is defined as being in the body.   60. The method of claim 59, wherein the step of determining the amount of light required to reach saturation relates to the imager gain level required for the dark frame.   61. The method of claim 60, comprising changing the mode of operation of the device after it has been defined as being in the body. A method for determining when an in-vivo device has entered the body,
Configuring dark frames at selected frame intervals in the device imager device;
Performing a substantially inappropriate exposure with at least one light source in each of the dark frames;
Measuring exposure of the image reflected during the dark frame as a function of light saturation threshold;
Defining that the device is in the body when the dark frame requires a substantial amount of light to reach saturation;
Changing the mode of operation of the device at defined time intervals after the device is defined to be in the body. An in-vivo imaging device,
At least one light source;
At least one imager;
At least one environmental measurement tool;
A light source, an imager, and a monitoring tool can be activated so that when the measurement tool measures at least one environmental parameter, the controller can define the position of the device based on the at least one environmental parameter An in-vivo imaging device comprising at least one controller.   66. The imaging device of claim 65, wherein the position of the device is at least one environment selected from the group consisting of extracorporeal, intracorporeal, intraoral, intrapharyngeal, esophageal, intragastric, and GI tract.   66. The imaging device of claim 65, wherein the controller is configured to change a mode of operation of the device with respect to the position of the device.   66. The imaging device of claim 65, wherein the environmental monitoring tool operates at at least one position selected from the group consisting of on the device, within the device, and outside the device. An in-vivo imaging device,
At least one light source;
At least one imager;
At least one environmental measurement tool;
An in-vivo imaging device comprising: a controller capable of defining a position of the apparatus based on at least one environmental parameter measured by the measurement tool and changing an operation mode of the apparatus according to the defined position . An in-vivo imaging device,
At least one illumination means for providing illumination to the device;
At least one imager means for recording an image for the device;
An environmental measuring means for measuring at least one environmental parameter;
An in-vivo imaging device comprising: illumination means, imager means, and at least one controller means for operating the measurement means. A method for determining the position of an in-vivo device comprising:
Measuring at least one environmental parameter in the environment surrounding the device using at least one measurement tool;
Determining a change in the at least one environmental parameter;
Determining that the device is in a new location based on the change in environment.   72. The method of claim 71, wherein the monitoring tool measures at least one characteristic of the environment and compares the at least one characteristic with a previous measurement of the characteristic.   72. The method of claim 71, wherein the tool is at least one tool selected from the group consisting of a pH monitor, a temperature monitor, and a light level monitor.   72. The method of claim 71, further comprising changing the mode of operation of the device after a new location has been defined. A method for determining the position of an in-vivo device comprising:
Measuring at least one environmental parameter in the environment surrounding the device using at least one measurement tool;
Determining a change in the at least one environmental parameter;
Determining that the device is in a new location based on the environmental change;
Changing the mode of operation of the device at defined time intervals after the device is defined to be in a new location. A method for changing an operating mode of an in-vivo device comprising:
Measuring at least one environmental parameter within at least one environment surrounding the device;
Changing the mode of operation of the device when an environmental change is sought.   77. The method of claim 76, wherein the environmental change is at least one change selected from the group consisting of a temperature change, a pH level change, and a light level change.   77. The method of claim 76, wherein the environmental monitoring is enabled by at least one tool selected from the group consisting of a pH monitor, a temperature monitor, and a light level monitor.   77. The method of claim 76, wherein the controller determines when a significant environmental change has been sought. A method for changing an operating mode of an in-vivo device comprising:
Measuring at least one environmental parameter within at least one environment surrounding the device using at least one environmental measurement tool;
Changing the mode of operation of the device when an environmental change is sought.

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