System for determining an abnormal skin dryness

Abstract

Scorecard 90 has a colour reference target and, in aspects, a backing portion having a region sized to receive a test patch. Test patch 100 that has previously been applied to skin is placed on the sc

Description

The colour reference target may comprise a first reference target having a known shape and having a colour corresponding to a colour of the test patch when fully dehydrated; a second reference target having a known shape and having a colour corresponding to a colour of the test patch when fully dehydrated, Additionally or alternatively the colour reference target may include a colour swatch including a region of cyan colour, a region of magenta colour, and a region of yellow colour and the method may comprise processing the regions of the image corresponding to the colour swatch so as to colour balance the image of the scorecard. The scorecard may further include one or more fiducial markers that have a known shape or pattern on the scorecard and the processing may use the fiducial markers to produce a modified image of the scorecard which is corrected for perspective and brought into focus. This may be performed by the system before the location and colour of the moisture indicator are determined, and before or after colour correction of the image using the colour reference target. The scorecard may include an adhesive portion that is spaced from the two reference targets that is configured to receive and adhere to a patch. The region for receiving the test patch may be identified by markings on the scorecard. The targets may have any known shape, but should not be of the same shape and size as the patch so that they are not mixed up when the image is captured. For example, the patch may be generally rectangular or square and the reference targets may be triangular. One target may match the first colour of the moisture indicator, for example blue and the other target may match the second colour of the moisture indicator, for example pink. According to a sixth aspect the invention provides a test kit comprising at least one scorecard and at least one compatible test patch. The test kit may include instructions on where to find a computer App for use with the scorecard. This may be in the form of a world wide web address (URL) that the user can type into a web browser, or a QR code that when read by a suitable QR reader directs a user to a location from which they can download the App to a mobile device such as a smartphone. The instructions may be printed onto the scorecard, or may be printed onto packaging or onto an instruction leaflet provided with the kit. The skilled person will appreciate that the system and method and other aspects of the invention may be used to determine an abnormal dryness of an area of skin of a person. This may provide an indication of the presence or severity of a range of conditions including but not limited to: Fabry disease, Guillain-Barre Syndrome, Parkinson’s disease, Alzheimer’s disease, Chemotherapy induced peripheral neuropathy, Human Immunodeficiency Virus infection, Cardiovascular Autonomic Neuropathy, Sjogren's disease and Lupus. The invention may also be used with synthetic skins or human skin as a test for the efficiency of anti-perspirants as a means for reducing or preventing perspiration of a skin without any modification of the system or method or computer program or scorecard. In this case, an antiperspirant may be applied to skin under a set of controlled conditions and the change in moisture content of a path or patches observed over time. There will now be described, by way of example only, one embodiment of the present invention with reference to and as illustrated in the accompanying drawings of which: Figure 1 is an overview of a system according to a first aspect of the invention; Figure 2 is a view of an alternative system to that of Figure 1; Figure 3 is view of a scorecard that can be used in the system of Figure 1 or Figure 2; Figure 4 is a plan view of a test patch for use in the system of Figure 1 or Figure 2; Figure 5 is a captured image of the test patch of Figure 4 applied to the scorecard of Figure 3; Figure 6 is a processed image generated from the image of Figure 5 in which the location of the targets and test patch have been enhanced and the image resized and in which the test patch is blue indicating an abnormal level of hydrosis; Figure 7 is a processed image corresponding to Figure 6 in which the test patch has turned pink-blue after applying to a foot for the predefined time indicating some abnormality but milder than for that of Figure 6; Figure 8 is a processed image corresponding to Figure 6 in which the test patch has turned completely pink after applying to a foot for the predefined time indicating a normal level of hydrosis; Figure 9 is a flowchart showing the steps performed in a test at the highest level; Figure 10 is a flowchart showing the sequence of prompts issued by the App on the smartphone that a user must follow to perform a reliable test; Figure 11 is a flowchart showing the main pre-processing steps performed by the processor on a captured image of a scorecard and test patch; Figure 12 is a flowchart showing how a percentage value is generated from the pre-processed images; and Figure 13 shows the results of application of a patch to (a) a normal foot, (b) a foot where there is some evidence of small fibre denervation, and (c) to a foot where sudomotor dysfunction has been detected. As shown in Figure 1, a system in accordance with a first aspect of the invention has three main component parts: an app 30 which runs on a smartphone 10 or another computer device, a scorecard 90 and at least one test patch 100. The smartphone 10 may be any suitable device owned by or accessible to a user, and as shown includes a processor, an area of memory 20 in which the app 30 is stored, a processor 70 and a camera 80. The skilled person will appreciate that a smartphone has other features including a display and a user interface. The later is often integrated into the display using a touch sensitive screen. The user interface enables the user to operate the device and to follow prompts generated by the App when it is running on the device. The scorecard 90 is shown in Figure 3 of the drawings and comprises a white card backing part 91. Printed on the front of the scorecard 90 are several colour reference targets. These include a first target 92 and a second target 93 that are in the shape of a triangle, although other shapes could be used The shape is intentionally selected to be unique on the scorecard to enable the location of these targets to be identified easily in the captured image. The colour of the first target 92 is blue to match the colour of a test patch that is fully dehydrated. The colour of the second target 93 is pink to match the colour of a test patch that is fully hydrated. Both have a triangular shape. The backing part 91 also carries two greyscale strips 94,95.The two targets and two greyscale strips are located around a central area which is marked with a boundary box that has the same size and shape as a test patch. This box shows where a test patch is to be fixed to the scorecard 90 by a user when carrying out a test. The scorecard also carries a colour swatch 97 having cyan, magenta and yellow regions. Again as shown this has a unique shape allowing it to be easily identified in the image. Finally, the scorecard carries two fiducial markers 98,99 of known pattern, size and location. The test patch 100 comprises a flexible patch like a conventional adhesive plaster that would typically be used to protect wounds on the skin. An example patch is shown in Figure 4 of the drawings. The test patch has a planar base 101 which has a layer of adhesive (not shown) on a rear face. This enables the patch to be stuck to the skin of a user, typically onto the foot when used to detect abnormal levels of moisture on the foot. The test patch 100 has a central permeable carrier 102 impregnated with a dried cobalt(II) chloride solution. In this state the carrier has a blue colour. Prior to use the test patch 100 may be stored in a moisture proof pouch or covered by a moisture proof removable skin. When fully hydrated, as would occur over a defined period of time when stuck to a foot of a person with a normal level of hydrosis, the hydrated cobalt(II) chloride turns pink. The time taken to turn pink all over when stuck to a foot of a person with normal levels of hydrosis is determined through tests of the test patches and this time is used as the dwell time for which the patch is to remain on the foot before removal. In the case of a commercially available neuropad® test patch this time is set as 10 minutes. The system may be used to perform the following method steps as part of a process for determining if a user has an abnormal level of hydrosis of their foot, as would be the case if there was nerve damage due to diabetes. The steps are shown in Figure 9 and Figure 10. The start point is for the user to download the App to their smartphone if they have not already done so. They must then start the App running where it will prompt the user to follow a set of steps that ensure an accurate test is performed. Once the steps have been followed the results of the test are displayed by the smartphone. The first prompt from the App is for the user to take a fresh test patch and apply to the foot for the predetermined duration, for example 10 minutes, before removing. The second prompt is for the user to fix the patch to the marked area of the scorecard. The adhesive on the back of the patch will be sufficient to stick the patch to the scorecard. The third prompt is for the user to turn on their camera and point the smartphone at the scorecard. The app will detect the edge of the scorecard and prompt the user when the scene of the scorecard is correct, i.e., not too far away or too close to the camera. Once the scorecard is correctly imaged by the camera the App prompts the user to capture an image of the scorecard. The App then saves this to a database stored in the memory of the smartphone along with the date and time of the captured image. Once the image is captured, the user is prompted to wait whilst the image is processed. The steps performed during processing may be as follows. The core numerical processing is done with an open-source library called OpenCV, a tried and tested piece of software with an incredibly high reputation amongst the numerical science community the world over. Let us refer to the initial image as ImO. This image, ImO, undergoes a pre-processing' stage then the resulting image is passed to a further process which attempts to isolate the bounds of the patch from the captured image prior to the main processing stage. Pre-Processing Stage This stage converts the colour space of the uploaded image (ImO) into a colour space known as COLORBGR2RGB. This is because the internal software uses an OpenCV function called imread()' to load ImO into memory and the ordering of the colour channels is Blue, Green, Red, but for subsequent processing we require that the colours be ordered in the more standard Red, Green, Blue. Once this is done, the image is then resized, maintaining the aspect ratio, to a height of seven hundred and fifty pixels. A process of colour-correction is then done by calculating the white balance of the image. This colour processing uses the colour of the colour reference targets on the scorecard as seen in the captured image. An optional process of image correction to remove the effects of perspective and focusing of the capture device may be performed by analysing the regions of the image that correspond to the fiducial markers. In this stage the image is distorted until the shape of the markers matches the known shape of the markers. For example, where the markers are square they will not be square in an image of the scorecard captured off axis but will be square in the distorted image after this processing step. They will also be brought into focus and in doing so the rest of the image of the scorecard can also be deemed to have been brought into focus. Using the value determined from the previous step, the image is then converted to a gray scaled image and passed through an adaptive Gaussian threshold filter, then a morphological process is applied to the resulting grayscaled image to help identify the required target parts of the image. A process of dilation and erosion are used to enhance important parts of the image. The result of the pre-processing stage is a set of three images, the initial resized copy, the initially dilated image, and the white-balanced image. These are used further down the algorithmic chain to produce the final percentage score of the source image. Main Processing stage - Test patch Detection The next step is to use the first two images returned from the pre-processing stage to isolate and pin-point the location of the fixed Pantone reference triangles 92.92 and of the other optional fiducial markers 98,99. These are of a known colour content and the algorithm knows to look for these patches to both correct any current image values and to also fully locate the test patch area within the image data. The returned values from this stage are the image data containing the test patch pixel data, the blue and pink, the grayscaled and original images. Main Processing stage- Percentage Calculation The final step is to now calculate the percentage of the processed image that is deemed to be pink, blue, or some value in between. This is done by examining every single point in the final image frame, and then, using the previously derived values for the pink and blue triangles from the framing card, the Euclidean distance in LAB colour-space is calculated, once for the distance between the reference blue colour and the pixel under examination, and again for the reference pink colour and the pixel under examination. The final percentage value is calculated as: pixels deemed blue Percentage = ---------------------------------------* 100 pixels deemed blue + pixels deemed pink This percentage value is stored in the database alongside the captured image for future reference. For example, this will allow a user to track the percentage over time and to see if their symptoms are becoming worse or improving. 5 Figure 2 shows an alternative in which the smartphone 10 is connected to a remote server 300. The connection is made over a communication network 200, for instance a cellular network or a wireless or wired connection to the internet. The remote server receives captured images from the phone or the percentage results values or both. If only captured images are sent these may be stored at the server for later access by the 10 smartphone user or a physician. The skilled person will appreciate that many modifications are possible whilst remaining within the spirit and scope of the invention. For example, instead of a smartphone the user may capture images using any colour camera device and upload the 15 images to a computer or tablet and transmit those images to a remote server for processing. Alternatively, a tablet device or any computer with an integral camera can be used.

Claims

1. A system for use in determining a skin dryness by processing images of a test patch of the kind comprising a membrane impregnated with a moisture indicator which has a first colour in the dry anhydrous state, and which changes to a second colour at a certain moisture content which corresponds to normal skin moisture, the system comprising:A user operable computer device having a camera, a processor, and an area of memory, a computer program stored in the memory of the user operable device, a scorecard having at least one colour reference target;in which the computer program causes the user operable computer device to process an image of the scorecard with a test patch placed on it after the test patch has been applied to an area of skin, the processing determining the dryness of the area of the skin.

2. A system according to claim 1 in which the moisture indicator comprises cobalt (II) chloride which has blue colour when in the dry anhydrous state and a pink colour when at the certain moisture content.

3. A system according to claim 1 in which the colour reference target comprises a first target which has a colour that corresponds to a fully dehydrated test patch and a second target having a colour that corresponds to a fully hydrated test patch and a region in which a test patch can be placed.

4. A system according any preceding claim in which the computer program causes the computer device to process the captured image to extract a two-dimensional image of the test patch which is colour balanced using the colours of the colour reference target or targets as seen in the captured image.Additionally or5. A system according to any preceding claim in which the colour reference target includes a colour swatch including a region of cyan colour, a region of magenta colour, and a region of yellow colour.In this case the system may process the regions of the image corresponding to the colour swatch so as to colour balance the image of the scorecard.

6. A system according to any preceding claim in which the scorecard further includes one or more fiducial markers that have a known shape or pattern, optionally a known size and optionally a known location on the scorecard and the processing may use the fiducial markers to produce a modified image of the scorecard which is corrected for perspective and brought into focus.

7. A system according to any preceding claim configured to store in a database in the memory captured images captured over a period of time using the camera, or the processed images, and to store alongside each image the results of the processing of the captured image.

8. A system according to any preceding claim in which the computer program is configured to cause the processor to process the results in the database to determine if the abnormality is changing over time and in the even that a change is detected over time to present a message or alarm to the user.

9. A system according to any preceding claim in which the scorecard comprises a backing portion having a front face which is provided with markings defining an area of the front face to which a test patch can be adhered.

10. A system for use in determining a skin dryness by processing images of a test patch of the kind comprising a membrane impregnated with a moisture indicator, which has a first colour in the dry anhydrous state, and which changes to a second colour at a certain moisture content which corresponds to normal skin moisture, the system comprising:a user operable computer device having a camera, a processor and an area of memory, a computer program stored in the memory of the user operable device,a scorecard having at least one colour reference target, for example a first target which has a colour that corresponds to a fully dehydrated test patch and a second target having a colour that corresponds to a fully hydrated test patch and a region in which a test patch can be placed, and ;in which the computer program causes the user operable computer device to capture an image of the scorecard with a test patch placed on it after the test patch has been appliedto an area of skin and to transmit the captured image across a network to a remote server that is configured to process the image to determine a dryness of the area of the skin.

11. A method of determining a skin dryness by processing images of a test patch of the kind comprising a membrane impregnated with a moisture indicator, which has a first colour in the dry anhydrous state, and which changes to a second colour at a certain moisture content which corresponds to normal skin moisture, the method comprising:capturing an image of a test patch that has previously been stuck to an area of skin together with an image of a scorecard, the scorecard having at least one colour reference target and a region in which a test patch can be placed;processing the captured image to identify the colour reference target and the patch;calibrating the colours in the captured image using the colours of the captured target, andanalysing the image of the patch in the captured image to determine the percentage of the patch that has the first colour and the second colour.

12. A method according to claim 11 comprising capturing the image on a portable device such as a smart phone.

13. A computer program which when operable on a user device, such as a mobile phone, causes the device to perform the method of the claim 12 or claim 13.

14. A scorecard for use in combination with a test patch of the kind comprising a membrane impregnated with a moisture indicator, which has a first colour in the dry anhydrous state, and which changes to a second colour at a certain moisture content which corresponds to normal skin moisture, , the scorecard comprising:a backing portion;at least one colour reference target, andand in which the backing portion includes a region that is sized to receive a test patch.

15. A scorecard according to claim 14 in which the colour reference target comprises a first reference target having a known shape and having a colour corresponding to a colour of the test patch when fully dehydrated;a second reference target having a known shape and having a colour corresponding to a colour of the test patch when fully dehydrated,16. A scorecard according to claim 14 or claim 15, in which the colour reference target includes a colour swatch including a region of cyan colour, a region of magenta colour, and a region of yellow colour and the method may comprise processing the regions of the image corresponding to the colour swatch so as to colour balance the image of the scorecard.

17. A scorecard according to any one of claims 14 to 16 which further includes one or more fiducial markers that have a known shape or pattern on the scorecard and the processing may use the fiducial markers to produce a modified image of the scorecard which is corrected for perspective and brought into focus.

18. A scorecard according to any one of claims 14 to 17 which includes an adhesive portion that is spaced from the two reference targets that is configured to receive and adhere to a patch.

19. A test kit comprising at least one scorecard as defined in any one of claims 14 to 18 and at least one compatible test patch.

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