AN ADAPTER FOR COUPLING A CAMERA UNIT TO AN ENDOSCOPE, A METHOD OF RECORDING IMAGE AND A COMPUTER PROGRAM PRODUCT

The invention relates to camera unit adaptor for coupling an addon camera unit on a portable electronic device to an endoscope providing an image of less accessible structures.

In a clinical context, dedicated photography devices are known for 5 recording images via endoscopes. However, such devices are relatively

complex to handle and operate, heavy and expensive.

Application of a digital compact camera is also cumbersome since most compact camera's are provided with a zoom lens requiring a complex, adjustable connection to the endoscope.

10 When taking a picture using an add-on camera that is provided on a portable electronic device, such as a mobile phone, a smart phone or a tablet, a desired image from the endoscope can be over exposed.

It is an object of the invention to provide camera unit adaptor, wherein the above-mentioned disadvantage is reduced. In particular, the

15 invention aims at obtaining a camera adaptor that enables convenient

photography of endoscope images using a camera functionality on

commercially available portable electronic devices. Thereto, according to an aspect of the invention, the adaptor includes a frame attachable, in a pre- specified lateral position, to a front side of a camera unit and connectable to 20 a proximal end of an endoscope, the frame further including a strip of light

guiding material being provided with an opening, wherein the strip covers a region of the camera unit's front side where an optical sensor and a flash light source of the camera unit are located, the opening being aligned with the camera unit's optical sensor when the frame is attached to the front side 25 of the camera unit.

By applying the flash light source in combination with the strip of light guiding material, pixels of the recorded image surrounding the endoscope image of interest are illuminated, so that the light intensity range of the pixels associated with an image portion of the endoscope on the one hand, and the pixels associated with an image portion surrounding the endoscope image reduces. Then, an effect of over exposure is also reduced since the camera unit may store the image pixels more efficient, assigning available bits to pixel values in said reduced intensity range.

Further, by providing a frame for attachment to a camera unit and for connection to a proximal end of an endoscope, proper alignment of the optical sensor, the strip, the strip opening and the endoscope can easily be realized, requiring less skills to hold both the endoscope and a camera unit.

In principle, the camera unit adaptor can be used with any add-on camera unit on a portable electronic device, so that medical personal can easily make pictures with commercially available cameras on mobile phones, smart phones etc. Such images can be recorded in a clinical setting. In addition, also other professionals using an endoscope may apply a camera unit adaptor according to the invention for making images.

The invention also relates to a method of recording an image.

Further, the invention relates to a computer program product. A computer program product may comprise a set of computer executable instructions stored on a data carrier, such as a flash memory, a CD or a DVD. The set of computer executable instructions, which allow a

programmable computer to carry out the method as defined above, may also be available for downloading from a remote server, for example via the Internet, e.g. as an app.

Other advantageous embodiments according to the invention are described in the following claims.

By way of example only, embodiments of the present invention will now be described with reference to the accompanying figures in which Fig. 1 shows a schematic perspective view of a front side of a camera module;

Fig. 2 shows a schematic perspective view of a front side of a camera module adaptor according to the invention;

Fig. 3a shows a schematic cross sectional view of the camera module adaptor shown in Fig. 2 attached to a camera module;

Fig. 3b shows a strip of light guiding material in the camera module adaptor of Fig. 3a;

Fig. 4 shows an image recorded by the camera module as shown in Fig. 1;

Fig. 5 shows a graph of light intensities of pixels in the image shown in Fig. 4; and

Fig. 6 shows a flow chart of an embodiment of a method according to the invention.

The figures are merely schematic views of a preferred embodiment according to the invention. In the figures, the same reference numbers refer to equal or corresponding parts.

Figure 1 shows a schematic perspective view of a front side 2 of a camera module 1. The camera module 1 is provided with an optical sensor 3 and a flash light source 4, located within a region 5 of the camera unit's front side 2. The camera module 1 is an add-on module on a portable electronic device 41 such as a mobile phone, a smart phone or a tablet. The front side 2 may include further structures, such as apertures of a built-in loud speaker unit or switches for operating the electronic device 41. As shown, the front side 2 of the camera module 1 has a generally rectangular design, including a top edge 6, a bottom edge 7, a first side edge 8 and a second side edge 9. However, the geometry can deviate from the

embodiment shown in Fig. 1. As an example, the front side 2 may have rounded corners. Further, the surface of the shown front side 2 is mainly flat. As an alternative, the front side 2 may have, in principle, a non-flat surface, e.g. a curved surface. For ease of reference, an orthogonal coordinate system is oriented such that the front side 2 of the camera unit 1 extends in a x-direction and a y-direction wherein a z-coordinate, in the front direction of the camera unit 1, is constant.

The optical sensor 3 can be implemented as a semiconductor device such as a CMOS or CCD unit.

Figure 2 shows a schematic perspective view of a front side 12 of a camera module adaptor 11 according to the invention. The camera module adaptor 11 is provided with a frame 13 that is attachable to the front side 2 of the camera unit 1 shown in Fig. 1. The front side 12 has mainly the same geometry as the front side 2 of the camera unit 1. In the shown embodiment, the geometry is generally rectangular, and the surface of the front side 12 of the camera module adaptor 11 is generally flat, so that the front side 12 of the adaptor 11 may follow the surface of the camera module's front side 2. The front side 12 of the adaptor 11 has a top edge 16, a bottom edge 17, a first side edge 18 and a second side edge 19.

The frame 13 includes a strip 14 of light guiding material. The strip 13 is provided with an opening 15. When attached to the camera unit 1, the frame 13 of the adaptor 11 is located in a pre-specified lateral position with respect to the front side 2 of the camera unit 1, i.e. the adaptor 11 is fixed in a direction x and a direction y with respect to the front side 2 of the camera unit 1. Then, the strip 14 covers the region 5 of the camera unit 1 where the light sensor 3 and the flash light source 4 are located. Further, the opening 15 is then aligned with the optical sensor 3 of the camera unit 1.

The frame 13 further includes a connector element 20 for connection to a proximal end 30 of an endoscope.

Figure 3a shows a schematic cross sectional view of the camera module adaptor 11 attached to the camera module 1. The cross sectional view is taken along a cross section along a transverse plane A extending in the x-direction and z-direction, through the strip 14 and transverse to the orientation of the front side 12 of the adaptor 11, see Fig. 2. The connector element 20 includes an opening 21 aligned with the opening 15 of the strip 14. The connector element 20 includes an annular element for clampingly receiving a proximal end 30 of the endoscope, thus providing a snap connection. The frame 11 is further provided with clamping elements 23 clampingly surrounding the first and second side edges 8, 9 of the front side 2 of the camera unit 1.

It is noted that the frame 11 can be attached to the camera unit 1 in various other ways, e.g. by clamping the top edge 6 and the bottom edge 7 of the camera unit's front side 2, and/or by using another mechanism for attaching the frame to the camera unit such as a magnetic connection, a screw connection and/or by surrounding not merely the side edges 7, 8 of the camera unit, but also a back side of the camera unit e.g. using an envelope structure.

When the frame 11 is assembled to the camera unit 1 and to the proximal end 30 of the endoscope, the proximal end 30 of the endoscope is aligned with the strip opening 15 of the strip and with the optical sensor 3 of the camera unit 1.

As also shown in Fig. 3a, the flash light source 4 is integrated in the front side 2 of the camera unit 1. The flash light source 4 can be implemented as a LED or a multiple number of LED's. The light of the flash light source 4 propagates through a lens element 24 when leaving the camera unit 1. External light L directed to the optical sensor 3 travels through a window 25 and a lens module 26 before reaching the optical sensor 3. The lens module 26 generally includes a lens having a fixed focal length. The flash light source 4, the lens element 24, the optical sensor 3, the lens module 26 and the window 25 are included in the camera unit 1 that is integrated in the portable electronic device 41.

Fig. 3b shows the strip 14 of light guiding material in the camera module adaptor 11 in more detail. In Fig. 3b, the top part shows the strip 14 in a front view, while the bottom part shows the strip 14 in a cross sectional view, at the level of the opening 15.

Preferably, the light guiding material in the strip 14 includes a transparent thermoplastic such as PMMA. However, also other light guiding material could be applied, e.g. glass. In the shown embodiment, the strip 14 is at least partially coated, on the side facing away from the camera unit 1, with a light impenetrable coating layer 27 to counteract that light propagating through the strip 14 leaks away, in a direction away from the camera unit 1. The operation of the flash light source is controlled by a control unit for turning on the flash light source. The control unit can be implemented as processor loaded with specific software driving the flash light source.

Figure 4 shows an image recorded by the camera module 1. Since the endoscope has a substantially circular cross sectional profile, the image 40 contains a relatively small disc shaped image zone 41 associated with visual information from the endoscope interior, and a relatively large border image zone 42 surrounding the disc shaped image part zone 41. The border image zone 42 represents optic information of structures outside the endoscope interior, e.g. wall portions of the endoscope and/or frame parts of the adaptor 11. Usually, such optic information is not of interest for the user and does not contain visible information of interest. When applying a lens having a fixed focal length, no optical zoom function is available, so that the relative size of the image part zone 41 with respect to the border image zone 42 is fixed.

When the endoscope is provided with a light source for illuminating the structures at a distal end of the endoscope, the light intensities of the pixels in the disc shaped image zone 41 are generally high, while light intensities of the pixels in the border zone 42 are generally much lower. Figure 5 shows a graph of light intensities L of pixels in the image shown in Fig. 4. The graph visualizes in a first graph section 43 the light value of structures represented by image pixels Pi in the disc shaped image part 42. Similarly, the graph visualizes in a second graph section 44, 45 the light value of structures represented by border pixels Pb in the border image zone 42. Due to the illumination of the endoscope, the image pixels Pi have a relatively high value, while the border pixels Pb generally have a relatively low value, see the lower second graph section 44. The intensity levels of the image pixels Pi and the border pixels Pb are present in a first range Ri.

Since the dynamic range of the optical sensor 3 is limited, the image pixel Pi values are than represented by extreme high values while the border pixels Pb are represented by extreme low values. In other words, the disc shaped image zone 41 is nearly white while the border image part 42 is nearly black. The image zone is over exposed.

According to an aspect of the invention, the flash light source 4 is switched on when the image from the endoscope is recorded by the camera unit 1. Then, the light F from the flash light source 4 enters into the strip 14, propagates towards the strip opening 15 and is incident on the optical sensor 3, in the border zone 42, thereby contributing to a higher light intensity level of the border pixels Pb. The intensity of the border pixels Pb raises to higher levels as represented by the higher second graph section 45.

Since the intensity levels of the image pixels Pi and the border pixels Pb are now with a second range R2, significant smaller than the first range Ri, the dynamic range of the optical sensor is used more efficiently. Advantageously, more bits are now available for the representation of the image pixels Pi, providing a meaningful image of the image pixels Pi in the image zone 41.

Advantageously, the light intensity of the flash light source 4 is set such that light F entering the optical sensor 3 via the strip 14 and the light L entering the optical sensor 3 via the proximal end 30 of the endoscope are in the same order of magnitude.

Further, the colour of the light F entering the optical sensor 3 via the strip 14 is optionally set such that said colour is similar to the colour of the light L entering the optical sensor 3 via the proximal end 30 of the endoscope.

As a further option, not merely a single image is recorded, but a multiple number of images. In principle, the multiple images can be taken with short intermediate time intervals, obtaining a sequence of images forming a video.

By using the above-described camera unit adaptor in combination with an endoscope, images can be recorded from structures that are less accessible, e.g. in the medical field or in the non-medical field of remote analysis of structures. The endoscope can be either rigid or flexible. In combination with a camera unit on a mobile (smart) phone, quick and convenient photography is available.

As an example of clinical, medical applications, it is noted that the adaptor can be used for diagnosis / surgery via ENT related apertures in the human body, e.g. for visualizing the ear drum or paranasal sinus, or for inspection of stomach or other intestine organs. The images can be taken either in an outpatient setting or on any location in or outside a hospital. As an example of non-medical applications, it is noted that the adaptor can be used for inspection of engine parts that are visually less accessible.

Figure 6 shows a flow chart of an embodiment of the method according to the invention. The method is used for recording an image. The method comprises a step of providing 110 an endoscope providing an image of less accessible structures, a step of providing 120 a camera unit including an optical sensor and a flash light source on its front side, a step of providing 130 a strip of light guiding material being provided with an opening, a step of covering 140, with the strip, a region of the camera unit's front side where the optical sensor and the flash light source of the camera unit are located, a step of aligning 150 the proximal end of the endoscope with the opening of the strip and with the optical sensor of the camera unit, a step of switching 160 on the flash light source, and a step of activating 170 the optical sensor.

The method of recording an image can be performed using dedicated hardware structures, such as FPGA and/or ASIC components. Otherwise, the method can also at least partially be performed using a computer program product comprising instructions for causing a processor of a computer system or a control unit to perform the above described steps of the method according to the invention, or at least the step of switching on the flash light source when the image is to be recorded. All (sub)steps can in principle be performed on a single processor. However, it is noted that at least one step can be performed on a separate processor. A processor can be loaded with a specific software module. Dedicated software modules can be provided, e.g. from the Internet.

The invention is not restricted to the embodiments described herein. It will be understood that many variants are possible.

As an example, the snap connection between the camera unit adaptor can be replaced by another connection type, e.g. a screw connection.

Other such variants will be apparent for the person skilled in the art and are considered to fall within the scope of the invention as defined in the following claims.