WO2009063185A1

WO2009063185A1 - Test results reading method and apparatus

Info

Publication number: WO2009063185A1
Application number: PCT/GB2008/003796
Authority: WO
Inventors: Alexander Robert Campbell
Original assignee: Surescreen Diagnostics Limited
Priority date: 2007-11-14
Filing date: 2008-11-12
Publication date: 2009-05-22
Also published as: GB0722311D0

Abstract

A method and apparatus for reading, recording and optionally transmitting results from rapid point of care tests and drug tests with results that may be recorded as positive/negative, quantifiable, semi-quantitative, quantitative, treated statistically, and optionally recorded at various preferred wavelengths, when used on any commercially available Pocket PC, PDA, computer or bespoke device. Results so produced include summary of data, positive/negative, quantifiable or semi-quantitative results, and can be directly viewable, readable, transmissible, storabie, or automatically put into a suitable report format for viewing or transmitting to remote facilities.

Description

Test Results Reading Method and Apparatus

The present invention relates to methods and apparatus for reading, recording and processing results taken from photo illustrative tests

There currently exists a wide range of immunoassay screening tests that are read visually for a simple positive or negative result of the condition the test is designed for and these include drug tests, hormonal tests such as pregnancy tests, health screen or environmental screens and the like.

Such tests currently suffer from operator error in reading them and visually reading these tests requires additional work in manually logging the results. There are significant benefits in having a system that can automatically log results into a computer system or a data retrieval system. Such a step requires accurate reading and recording of the presence or absence of an indication region on the test.

Additionally, although immunoassay tests are generally regarded as screening devices for simple yes or no (i.e. positive or negative) results, there exists the capability to use immunoassay test as quantitative or semi-quantitative tests in a number of applications. Such a step requires accurate reading and recording of the intensity of the indication region on the test.

In order to be accurate such a reading device must be capable of accurately monitoring the indicated zone (called a test line or test result) without ambiguity as to background reflections, background colour or contamination (for example from darkly coloured urine), and accommodate streaking of the test from poor flow characteristics, and variability of the quality control region (called the control line) that is applied to ensure the test has run properly and that the test is not damaged. Immunoassay screening is used in many applications in modern medicine and drug testing, such that several million tests are manufactured and used every day worldwide. Most of these products such as pregnancy tests, menopause tests, drug tests and the like are read visually as positive or negative results because the visual indication from the test is fairly easy to interpret by the user.

In an immunoassay test, the detection system most commonly employed is the labelling of an antibody by a conjugated gold particulate complex that is often a magenta colour. This antibody conjugate complex binds to an antibody commonly positioned on a piece of membrane as a 'test' area over which the test solution travels by capillary action. In some types of test known as a direct immunoassay, a complex product binds to antibody on a 'test' area thus the presence of a bound test area constitutes a positive test result. In other tests called 'competitive immunoassay' the conjugate is so designed that it becomes blocked by the substance being detected, so that the antibody binding site is now occupied, therefore there is no opportunity for a test area to develop; in which case the absence of a test area constitutes a positive test result.

It will be seen by those practiced in the art, that many tests in current use typically have a magenta colour on the test area when the result is positive and some others have a magenta coloured test area when the result is negative.

It is therefore vitally necessary to know what type of test is being used when interpreting the results because the consequences of reading the test wrongly could be dire.

Even if the labelling method does not use a magenta colour it is usually necessary to incorporate a visually coloured medium such as particular or dye labelling which may be any suitable colour for visual reading. Sometimes it may be more appropriate to incorporate a non-visually coloured medium for the label, for example fluorescent dye, or magnetic particle labelling with developer may be required for certain substances and certain sensitivities, in order to cater for these technologies it is necessary to use a program with as wide a range of detection capabilities as possible. In this application such eventualities are accommodated for by using a highly sensitive colour camera with a wide spectrum range, and a dedicated algorithm that is specially adjusted to take care of spurious artefacts in the appearance of the result.

Visually read tests may be satisfactory once the correct training has been carried out but there are many instances when reading the result is difficult. One common application of immunoassay tests is drug detection for illicit drugs in urine or oral fluid from a donor. One such instance is the use of these tests under difficult lighting conditions. A typical example might be the use of a drug test to detect drug abuse in drivers of vehicles at night under poor lighting conditions.

Drug users sometimes abstain from drug taking if they know they may be tested. This situation commonly occurs in employment screening for example. As the level of drug in the body decays the donor will reach a stage where there are traces of drug in the system that are close to the sensitivity level (or 'cut off level') of the drug. Under these circumstances the intensity of the test area will be very faint which is far from ideal for reading visually. Drug users who have a drug level that is a little below the sensitivity of the test will produce partially reacted antibody and these will produce a faint test area. Those who have a drug level that is very close to the test sensitivity will have an extremely faint line that will be inconclusive. In such circumstances the donor should be given the benefit of the doubt but in such cases the conviction of the person carrying out the test is compromised by doubt and the test can be seen as an unreliable product. In such cases, a device that can read the intensity of the indication and not just the presence or absence of the indication would be ideal.

It can therefore be seen from these examples that an automatic reader for these products is highly desirable. Having worked with Police throughout Europe we have recognised that such a reader must advantageously be compact, easy to use, be accurate and reliable, work in extremes of temperatures, be easily carried, be designed around specific Police requirements, be easily replaced if damaged, conform to various current electrical requirements, have a long charge and have a iong operating life between charges, and be economically priced. Such requirements also generally apply to other users. Specifically such an instrument should be capable of being carried on Police motorcycles, and be suitable for use in poor lighting conditions. The program must be easy to use, intuitive, capable of being presented in multilingual form, cross- compatible, be integrated with Police procedures and Police documentation, accurate, capable of determining unsuitable results, capable of identifying poor quality tests, and flag up to the user any result why a result could be dubious and preferably avoid false positives wherever possible.

Hitherto, readers for medical products have become a crowded art, and numerous designs exist based on CCD cameras or small poor quality webcams attached to laptops or desktop computers.

Pierce Jones Osborn et al. (ZA200101216; GB2339615) developed a hand-held reader for oral drug tests based on a reading device comprising an imaging CCD camera viewing a test cassette via a half-silvered mirror with three LEDs set at 430nm, 565nm and 660nm to illuminate the test monochromatically (a green 565nm LED is used for gold conjugate based tests). Positioning of the test device is critical with measurements of test areas being made with reference to the control area of the test device. Results are calculated based on intensity of test area, background area and control area according to a calculation described in the patent.

James Wickstead et al. (US2006292040) developed a hand-held reader for rapid on-site screening and drug testing based on a CCD camera viewing the test device directly, and a PDA/iPAQ offering computing power and results viewing within a bespoke housing, illuminating the test device with green light and producing in effect a monochrome image. Positioning of the test device for this application is critical with measurements of test areas being made with reference to the control area of the test device. Results are calculated based on intensity of test area, background area and control area according to a method described in the patent.

Cozart (UK 2339615) provides an immunoassay device with a monochrome CCD camera viewing 324 x 240 elements via an angled mirror and a timing means and comparing the intensity of a control zone compared to the background and control zones via separate green illumination means set at 565nm wavelength. Each membrane is represented by an array of pixels and pixel intensities are summated over that entire array. The reader's result is based on a summation of all the pixels identified in the test position compared with a summation of all pixels in the control positions and background positions. The patent centres around the pixel array format and its algorithm.

Fig 1 shows a schematic description of the system as described, consisting in this example of a PDA and its charger, reader housing and carrying case as described generally in the patent application. For the purposes of illustration, Fig 2 shows a schematic isometric drawing of a typical rapid on-site test (10) as described generally in the patent application with its two test strips (12, 14).

, For the purposes of illustration, Fig 3 shows an isometric detail.

Fig 4 shows a side elevation of the reader housing (121 ) with the PDA reader (62) in position; and,

Fig 5 is a graphic illustration of a pixel value result output across a target image.

In accordance with aspects of the present invention there is provided a method of reading a photo illustrative test, the method comprising presenting an activated photo illustrative test to a camera to provide an image of a test area of the test, obtaining an image of the test area in the form of an array of pixels, analysing the image for a pixel value difference for at least one colour between adjacent pixels to a pre-determined pixel depth in the image, consolidating all or pre-determined groups of pixel values in rows of pixels to determine changes or transients in the image of the test area as an indicator of nature of the result from the photo illustrative test.

Also in accordance with aspects of. the present invention there is required a reading apparatus for a photo illustrative test, the apparatus comprising a camera to be associated with an illustrative test to obtain an image of a target area of the test, the camera associated with a processor to consider the image in the form of an array of pixels, the processor arranged to analyse the image for a pixel value difference for at least one colour between adjacent pixels to a pre-determined pixel depth in the image, consolidating all or groups of the pixel values in rows of pixels to determine changes or transients across the image of the test area as an indication of the nature of a result from the photo illustrative test.

Typically, more than one colour is utilised with regard to determining pixei vaiue differences between adjacent pixeis. Generally, each colour defines a two dimensional array for the test area.

Possibly, the target area is subject to illustrative illumination. Possibly, the illustrative illumination is infra-red radiation or ultra-violet radiation.

Generally, the image is taken in the form of red/green/blue (RGB) colour analysis. Alternatively, the image is optimised for particular radiation bands such as infra-red or ultra-violet. Generally the array of pixels is utilised with regard to the pixel value in order to identify changes in the test associated with particular photo luminescent or reactions with test chemicals for identification of a particular element within a sample. Generally the samples are presented in a liquid form.

Generally, changes in the pixel value are to a pre-determined depth and with respect to adjacent pixels or groups of the pixels to give an aggregate pixel value from a seed or centre pixel for the pixel value. Generally, the pre-determined depth is dependent upon analysis requirements and capabilities with regard to the photo illustrative test. Typically, the pre-determined depth is five.

Possibly, the pixels utilised to the pixel depth are weighted to a varying factor dependent upon a weighting factor for each position in the predetermined depth.

Generally, the camera is a colour camera. Typically, the camera incorporates an auto-focus. Typically, the camera will incorporate an integrated flash. Possibly, the camera operates by CMOS or CCD technology.

Generally, the camera will be presented in a holder to provide a set distance between the photo illustrative test and the camera. Possibly, the photo illustrative test is presented within a container and the camera forms part of a lid for the container. Generally, the container is light tight. Possibly, the apparatus includes a reflection mirror to increase the effective optical path length between the target area and the camera.

In accordance with further aspects of the present invention there is provided a method for portable apparatus for reading and processing results from rapid test devices for various applications consisting of PDA with colour camera, operating system and analysis algorithm, reader housing, carrying case and electrical charger(s) comprising more particularly:

a. PDA device comprising data entry facility, camera facility comprising colour camera preferably with close-up lens; white light illumination facility, viewing facility, computing facility, results display facility, storage facility, data transmitting facility and data archiving facility.

b. Image capture capability with the ability to choose the most appropriate wavelength to optimise the density of the image (for example with magenta lines choosing green image only to optimise the image) with image handling.

c. Analysis operating system based on algorithms that calculate difference between pixel values and their neighbouring pixels to a distance of n pixels. Possible weighting of these measurements to exaggerate differences in pixel values where appropriate; attempting to prevent incorrect analysis due to faint lines and/or uneven test line distribution. The use of a cut-off level for the product of these calculations to determine whether the test is positive or negative including an array of known possible test binding sites (also referred to as test lines), to search for values over these cut-off levels. More specifically, an overview of the algorithm used in one embodiment might be:

Given a test bitmap and element of that bitmap: pixel X, denoted as x(p.q) where p is its horizontal position (offset from 0) and q is its vertical position on the bitmap (offset from 0). For each q, where w is the total width of the bitmap and h is the total height of the bitmap (and p < w and q

< h). Array Y is a one-dimensional array storing test data.

For each q (such that 0 ≤ q < h): v [ ( (X(p,q)-X(p+1 ,q) ) + ( X(p,q)-X(p+2,q) ) +( X(p,q)- Y(q) = ∑ X(P+3,q) ) + ( X(p,q)-X(p+4,q) ) + ( X(p,q)-X(p+5₍q) )]

0 < p < u-

In a reasonably strong negative sample this will produce a result as shown in figure 5.

Since pixel values of this nature fluctuate both up and down on a negative result, and the algorithm is essentially a logistical way of measuring change, it is essential that both positive and negative change is measured. Included in the graph is a set of four positive cut-offs, and a set of four negative cut-offs; members of which are noted as a and b respectively. The third data series is the data obtained by the main algorithm noted as array q(0 to h). Cut-off levels, a and b can vary to any degree dependent mainly on the type of test used but also lighting conditions, type of camera and a number of other factors. In one embodiment cut-off levels like a and b are used to determine the result of the test on a test area by test area basis, such that:

Positive = (q(x) < a) v (q(x) > b) for all x inside those boundaries. Negative = (q(x) >a) ^Λ (q(x) < b) for all x inside those boundaries.

N. B. This method of analysis is shown to clarify the technique, although some embodiments of this design may analyse results differently such as the case of a negative result being signified by the absence of a test area.

A second couple of sets of cut-offs may also be added to this technique and used to strengthen the result decision process.

d. Database storage system with the ability to store test sample donor's data as well as analysis results, and raw analysis data from previous samples after being analysed. The ability to retrieve this information at any point for review, and optionally transmit this data to an auxiliary computer using wireless technology or physical connection. This system also encompasses the ability to produce reports for statistical observation and review.

e. Reader housing comprising substantially light-tight containment for the test being read, providing correct location and focal length to suit the particular lens utilised by the PDA.

f. Carrying case comprising containment for reader, reader housing and associated PDA charger(s).

The apparatus as above wherein tests for drugs, hormonal changes such as pregnancy, medical tests such as hepatitis, health screens such as cholesterol, environmental tests such as allergies and the like based on optical changes to intensity of test result may be read by the reader.

The apparatus as above wherein the medium to be tested may be oral fluid (saliva), blood, urine, food liquid product, water-based samples and the like may be read by the reader. We have recognized that the reader has to be based around a modular system for complete flexibility in reading test devices of all types such as urine drug tests, oral drug tests, medical screening tests for blood-based fluid, urine or oral fluid etc therefore we will describe the main embodiment and supplementary embodiments of the reader.

The reader program is based around a computerised system which incorporates the operating system, data inputting system, the reading system, the data handling system, the analysis system, the analysis interpolative and algorithmic system that determines the quality checking and assignment of the data, the support system for the test reporting, and support systems for displaying, transmitting, storing and securing the results, among others.

The computerised program is designed to be run on a wide range of

PDA and computer systems, and is preferably operated on a PDA (Personal Digital Assistant) which in one embodiment incorporates a colour CMOS camera, running a Microsoft Operating System designed for a smart device e.g. Windows Mobile 5.x. For the purposes of qualification and development an HTC Hermes 100 PDA has been used.

The colour camera incorporated within the device preferably has an automatic focusing system and an integrated flash plus built in picture handling facilities. Most modern PDAs, computers, Pocket PCs, and even some standard mobile phones have this facility. The system preferably includes a suitable holder for the camera and the test such that a suitable distance is maintained between the test and the camera within the range of the camera's focal length. It will be apparent to those familiar with camera technology that the closer the spacing can be to the closest focal length of the camera, the larger the image captured will be and hence the more accurate will be the data handling capability. This aspect partners favourably with a zoom facility which cuts down possible needed cropping of the image after capture. Image cropping after image capture can take up processing power of the system as well as adding to the required time of testing. However, as focal length shortens, the quality of the illumination deteriorates, therefore optimum conditions have been incorporated into the present design. Preferably the camera will have a close-up lens to reduce the stand-off between the camera and the PDA to a minimum. In one embodiment of the system the PDA preferably sits on a containment for the test such that the PDA forms the 'lid' of the containment and the test sits in a prescribed location at the base of the containment.

The PDA used for the purposes of qualification has a CMOS (Complementary Metal-Oxide-Semiconductor) camera, while many others practiced in the art have used CCD (Charge-Coupled Device) cameras. At the time of writing CCD cameras are considered a more mature technology, and CCD sensors are sometimes considered superior in image quality (particularly in low light environments) and flexibility. However, due to the nature of the technology, CMOS cameras can generally be implemented with fewer components, and provide data faster than CCDs as well as using less power. These factors would prove beneficial in a mobile device. Those practiced in the art will appreciate that monochrome CCD cameras are also better suited to simple systems rather than colour CCDs. However, monochrome cameras have certain disadvantages which this patent aims to overcome. Due to the prolific development of mobile devices such as mobile phones, PDAs, and the like; CMOS cameras have also become more widely available and there are more products available including this technology.

Preferably the system includes a carrying case for the PDA. Preferably the case also has room for rapid tests, PDA charger etc. Preferably the carrying case includes a section for (or is integral to) the PDA holding and locating system and the test location. Preferably the carrying case is robust and suitable for transporting, carrying in vehicles including motor cycles.

For the purposes of describing the system, the programme and its functions; the following general description will be of assistance.

The test to be read is conducted in the usual way and this can be any rapid test for which the programme is suitable. In this example, a rapid on- site drug test for oral fluid (10) consisting of two strips (12, 14) each of which contain several drug test areas wiii be used, in this example the ieft side of the test consists of a strip having (from the bottom) test target areas for PCP (common name phencyclidine), MET (common name methamphetamine) COC (common name cocaine) followed by a Control line, and on the right side (from the bottom) AMP (common name amphetamine), OPI (common name opiates), THC (common name cannabis) followed by a control line. However, any combination of these is possible including other drug types not mentioned here.

For the purposes of demonstration, the Reader is configured to accept samples from motorists, and will be further described as such for this application. However, the system is not confined to this configuration.

Referring specifically to the functionality of the PDA and computerized system itself for the detection of drug use with motorists, the test commences with entering of the details relevant to the test. Firstly, if the

PDA has not been used recently, it is switched on and the details relating to the test are entered. Preferably this includes the following details.

g. The programme is booted in memory through the Operating System. h. A form opens to allow the user to configure the device in a number of ways, such as scanning a test, viewing prior results etc. i. When scanning a test, the program asks for specific details to uniquely identify the test, viz: donor's title, first and second names, gender, data of birth etc. The device may also assign a unique identifier to the test such as a timestamp. j. The program asks for donor type (example: motorist; suspect, routine etc.) and driving license number. k. The programme then asks for the type of test to be used.

I. The programme then prepares and configures the camera for use. m. The reader is then placed in a suitable position for the picture to be taken. This may include a bespoke enclosure, a stand, part of the containment box, or a modification of the kit box in which tests are contained, for example. n. The reader takes a picture and analyses the result. o. Results are given in a Boolean fashion (Positive or Negative), with optional graphical representation and the ability to view the image captured from the test procedure.

This data may most conveniently be entered by typing in the data using the PDA's keyboard, or by use of the touch-screen QWERTY keyboard, or by using the writing-pad letter recognizer that forms part of the Windows

Mobile or Pocket PC software.

When capturing the image, the test (10) is put into the bottom of the reader housing (121 ) which preferably is an integral part of the carrying system comprising a carrying case (101) consisting of base (111 ), hinged lid (112), carrying handle (113), and securing catches (115). The system includes the PDA (62) and its charger (66). Preferably the PDA also operates and recharges from a 12 volt vehicle power supply (not shown). Preferably the carrying system also has room to transport rapid diagnostic tests (114). Once located into position, the reader PDA (62) is placed upon the top of the reader housing (121), forming a substantially light-tight seal with the upper face of the housing (65). From this position, the PDA (62) can photograph the test (68).

In one embodiment of the device, the algorithmic and data analysis systems operate in the following way. Once a 2-dimensional array of the image's pixel values has been obtained, the program will deconstruct the RGB data. Unlike prior art, this solution uses RGB data giving the ability to concentrate on one, two or all three of the RGB elements. In this embodiment where magenta labelling is used, the program uses only the G element of the colour value for each pixel. Since the device in this application is designed to detect changes from white to red, green is the most suitable colour in this embodiment to use for analysis in order to highlight the most significant change between pixel values. Hence, a new 2-dimensional array is produced using only the green element irrespective of the type of illumination provided for the picture. It should be noted that in other applications the same method of choice may apply, whereby the choice of RGB data is exercised, and the colour value or number of colour values are used in order to highlight the most obvious contrast in pixel definition.

In order to determine whether the test has produced a positive or negative result, the algorithm calculates the difference in pixel value (usually a range of 0-255 or more) systematically of each pixel below it to a variable depth. In this particular embodiment, this depth is 5. In which case, each element of the array is given a value attribute of the difference between the pixel itself and some of its neighbouring pixels. Taking an example pixel value X,

Since the depth is 5 in this example, the difference between each pixel and its neighbouring pixels are calculated (as shown above) , and the summation of these values is then attributed to X. [ X = X + (X - [X+ 1]) + (X - [X+2]) + (X - [X+3]) + (X - [X+4]) + (X - [X+5]) ]

Once this data has been calculated, the sum of each row is calculated and is used to form a new array which then forms the basis for further analysis in order to give a positive or negative result. So, for example pixel X will be given the new value:

157 + 172 + 194 + 231 + 186 + 170 = 1110

It should be noted here that the pixel depth of analysis (stated in this particular example as 5) is completely variable dependent on application, and in addition to this the different depths may or may not be weighted so that different distances from the origin pixel have different strengths. An example of this is shown below:

So, pixel X now becomes: 157 + 344 + 310 + 231 + 186 + 102 = 1330

After these calculations have been satisfied, the whole row of pixels is summated giving one array from 0 to 'image_width' by which to further analyse the image with.

Due to the nature of immunoassay-based tests, and the necessary capillary action involved with these tests, sometimes as the test dye bleeds and bonds to the test site (mentioned earlier) the dye is distributed unevenly, and sometimes the outcome is a strong line, with a gradient-like formation of colour. Since one of the possible applications for this device could involve immunoassay tests, this algorithm has been designed to produce favourable results if and when these unevenly distributed test results should occur. This part of the algorithm may be optional in particular embodiments but is usually included to minimalise false readings due to slow gradients over test areas that can prove difficult to detect with some other algorithms. Not only does adding neighbouring pixels to produce an accumulative value for each pixel help average-out imperfections with the image, the difference between pixel values as the line is detected is exaggerated, in addition to this, the vaiues put in the new array are on average n times (n being the pixel depth described above) what they were at the start of the exercise giving greater accuracy. Greater accuracy (greater range of values) helps form a more honed quantitative range as discussed earlier.

This algorithm also helps iron out small imperfections on the image (such as foreign specks of dirt on the test and 'streaking' which can be caused from darkly coloured urine)reducing their effect. Since the test can be wet when testing occurs, it is also necessary to account for reflections from illumination devices. Reflections on the wet strip could produce false results if not dealt with effectively. In this embodiment, reflections on the test are not a problem due to development of the flash facility.

Weighting the pixels in the method described above can help exaggerate the data even further.

[0002] In one example embodiment, the PDA is used to capture various data concerning the sample donor and stored in a database on the device. The device is then situated over the test allowing a suitable distance between the two in compliance with the camera's focal length. The image sensor, be it a CCD sensor or CMOS is then used to capture an image of the test situated below. Aspects of the present invention relate to a method and a reading apparatus for utilisation with respect to photo illustrative tests such as those utilised and referred to as immunoassay tests, which provide photo responsive results in the form of lines or tracks which can be identified in accordance with aspects of the present invention by considering pixel value differences across a test area. With regard to a test apparatus in the form of a reader, it will be appreciated the apparatus will incorporate a camera. The camera will be associated with an appropriate container for the photo illustrative test. The container can comprise a base container incorporating the photo illustrative test with a lid as indicated incorporating the camera or a photo conduit such as a fibre optic pathway to a camera. In any event, the containment is light tight such that the camera can take an image of a test area of the photo illustrative test. The image is then analysed as indicated above. Typically, such analysis will be achieved through a process and processor which may operate utilising an algorithm as described below. The algorithm illustrated is with regard to retrieving a green element from a red/green/blue colour range full of pixels.

The algorithm is responsible for retrieving the green element for each pixel on the target area image matrix. It then calculates differences between each pixel's neighbouring pixels to a depth of 5. The sum of these values is then allocated to a new array: val_sum_totT().

For y = min_h To max_h - 1 For x = min_w To max_w - 1 val = pic.GetPixel(x, y) valG(x, y) = val. G Next

For x = min_w To max_w - 6 val_dif_1(x, y) = vaIG(x, y) - valG(x + 1 , y) val_dif_2(x, y) = valG(x, y) - valG(x + 2, y) val_dif_3(x, y) = valG(x, y) - valG(x + 3, y) val_dif_4(x, y) = valG(x, y) - valG(x + 4, y) val_dif_5(x, y) = valG(x, y) - valG(x + 5, y) valG(x, y) = Nothing Next

For y = min_h To max_h - 1 For x = min_w To max_w - 6 val_sum_1(x) = val_sum_1(x) + val_dif_1(x, y) val_sum_2(x) = val_sum_2(x) + val_dif_2(x, y) val_sum_3(x) = val_sum_3(x) + val_dif_3(x, y) vai_sum_4(x) = vai_sum_4(x) + vai_dif_4(x, y) val_sum_5(x) = val_sum_5(x) + val_dif_5(x, y) val_sum_totT(x) = val_sum_totT(x) + val_sum_1(x) + val_sum_2(x) + val_sum_3(x) + val_sum_4(x) + val_sum_5(x)

'*^*DISPOSE** val_sum_1(x) = Nothing val_sum_2(x) = Nothing val_sum_3(x) = Nothing val_sum_4(x) = Nothing val_sum_5(x) = Nothing Next

Providing apparatus and a method which can be performed at remote locations by such personnel as policemen and ambulance workers has significant benefits. In such circumstances the apparatus needs to be small and portable to allow ready transportation and carriage with the limited storage space available in a vehicle or rucksack. In such circumstances care must be taken with regard to the optical lengths between the target area and the camera image. It will be understood that typically a reasonable length is required in order to allow the camera to focus appropriately upon the target area. This focal length or length between the camera and the target area can be a straight line or for convenience in accordance with aspects of the present invention a folded or convoluted optical path provided with mirrors to shorten the necessary housing and therefore package lengths for the apparatus in use. In such circumstances the apparatus and therefore the method may be more conveniently performed by personnel at remote locations. The mirror simply allowing the target area and the camera to be side by side so halving or otherwise truncating the overall length required for the apparatus.

Furthermore, it will be understood that certain reaction responses create certain changes in colour. These colour changes may be in the visible range or the ultra-violet or infra-red ranges of the spectrum. In such circumstances by appropriate illumination of the target area and/or optimising the camera for the desired interrogation for the characteristic radiation responses from the target area more focussed and tuned analysis can occur for particular analytical tests.

Claims

1. A method of reading a photo illustrative test, the method comprising presenting an activated photo illustrative test to a camera to provide an image of a test area of the test, obtaining an image of the test area in the form of an array of pixels, analysing the image for a pixel value difference for at least one colour between adjacent pixels to a predetermined pixel depth in the image, consolidating all or predetermined groups of pixel values in rows of pixels to determine changes or transients in the image of the test area as an indicator of nature of the result from the photo illustrative test.

2. The method as claimed in claim 1 wherein more than one colour is utilised with regard to determining pixel value differences between adjacent pixels.

3. A method as claimed in claim 2 wherein each colour defines a two dimensional array for the test area.

4. A method as claimed in any of claims 1 , 2 or 3 wherein the target area is subject to illustrative illumination.

5. A method as claimed in claim 4 wherein the illustrative illumination is infra-red radiation or ultra-violet radiation.

6. A method as claimed in any preceding claim wherein the image is taken in the form of red/green/blue (RGB) colour analysis.

7. A method as claimed in any preceding claim wherein the image is optimised for particular radiation bands such as infra-red or ultra-violet.

8. A method as claimed in any preceding claim wherein the array of pixels is utilised with regard to the pixel value in order to identify changes in the test associated with particular photo luminescent .or reactions with test chemicals for identification of a particular element within a sample.

9. A method as claimed in any preceding claim wherein the samples are presented in a liquid form.

10. A method as claimed in any preceding claim wherein changes in the pixel value are to a p re-determined depth and with respect to adjacent pixels or groups of the pixels to give an aggregate pixel value from a seed or centre pixel for the pixel value.

11. A method as claimed in claim 10 wherein the pre-determined depth is dependent upon analysis requirements and capabilities with regard to the photo illustrative test.

12. A method as claimed in claim 10 or claim 11 wherein the predetermined depth is five.

13. A method as claimed in any preceding claim wherein the pixels utilised to the pixel depth are weighted to a varying factor dependent upon a weighting factor for each position in the pre-determined depth.

14. A method as claimed in any preceding claim wherein the camera is a colour camera.

15. A method as claimed in any preceding claim wherein the camera incorporates an auto-focus.

16. A method as claimed in any preceding claim wherein the camera will incorporate an integrated flash.

17. A method as claimed in any preceding claim wherein the camera operates by CMOS or CCD technology.

18. A method as claimed in any preceding claim wherein the camera will be presented in a holder to provide a set distance between the photo illustrative test and the camera.

19. A method as claimed in any preceding claim wherein the photo illustrative test is presented within a container and the camera forms part of a lid for the container.

20. A method as claimed in claim 19 wherein the container is light tight.

21. A method as claimed in any preceding claim wherein the apparatus includes a reflection mirror to increase the effective optical path length between the target area and the camera.

22. A reading apparatus for a photo illustrative test, the apparatus comprising a camera to be associated with an illustrative test to obtain an image of a target area of the test, the camera associated with a processor to consider the image in the form of an array of pixels, the processor arranged to analyse the image for a pixel value difference for at least one colour between adjacent pixels to a pre-determined pixel depth in the image, consolidating all or groups of the pixel values in rows of pixels to determine changes or transients across the image of the test area as an indication of the nature of a result from the photo illustrative test.

23. Apparatus as claimed in claim 22 wherein more than one colour is utilised with regard to determining pixel value differences between adjacent pixels.

24. An apparatus as claimed in claim 23 wherein each colour defines a two dimensional array for the test area.

25. An apparatus as claimed in any of claims 22 to 24 wherein the target area is subject to illustrative illumination.

26. An apparatus as claimed in any of claims 22 to 25 wherein the illustrative illumination is infra-red radiation or ultra-violet radiation.

27. Apparatus as claimed in any of claims 22 to 26 wherein the image is taken in the form of red/green/blue (RGB) colour analysis.

28. Apparatus as claimed in any of claims 22 to 27 wherein the image is optimised for particular radiation bands such as infra-red or ultra-violet.

29. Apparatus as claimed in any of claims 22 to 28 wherein the array of pixels is utilised with regard to the pixel value in order to identify changes in the test associated with particular photo luminescent or reactions with test chemicals for identification of a particular element within a sample.

30. Apparatus as claimed in any of claims 22 to 29 wherein the samples are presented in a liquid form.

31. Apparatus as claimed in any of claims 22 to 29 wherein changes in the pixel value are to a pre-determined depth and with respect to adjacent pixels or groups of the pixels to give an aggregate pixel value from a seed or centre pixel for the pixel value.

32. Apparatus as claimed in claim 31 wherein the pre-determined depth is dependent upon analysis requirements and capabilities with regard to the photo illustrative test.

33. Apparatus as claimed in claim 31 or claim 32 wherein the predetermined depth is five.

34. Apparatus as claimed in any of claims 22 to 33 wherein the pixels utilised to the pixel depth are weighted to a varying factor dependent upon a weighting factor for each position in the pre-determined depth.

35. Apparatus as claimed in any of claims 22 to 34 wherein the camera is a colour camera.

36. Apparatus as claimed in any of claims 22 to 35 wherein the camera incorporates an auto-focus.

37. Apparatus as claimed in any of claims 22 to 36 wherein the camera will incorporate an integrated flash.

38. Apparatus as claimed in any of claims 22 to 37 wherein the camera operates by CMOS or CCD technology.

39. Apparatus as claimed in any of claims 22 to 38 wherein the camera will be presented in a holder to provide a set distance between the photo illustrative test and the camera.

40. Apparatus as claimed in any of claims 22 to 39 wherein the photo illustrative test is presented within a container and the camera forms part of a lid for the container.

41. Apparatus as claimed in claim 39 wherein the container is iight tight.

42. Apparatus as claimed in any of claims 22 to 41 wherein the apparatus includes a reflection mirror to increase the effective optical path length between the target area and the camera.

43. A reading apparatus for a photo illustrative test substantially as hereinbefore described with reference to the accompanying drawings.

44. A method for portable apparatus for reading and processing results from rapid test devices for various applications consisting of a PDA with colour camera, operating system and analysis algorithm, reader housing, carrying case and electrical charger(s) comprising more particularly:

c. Analysis operating system based on algorithms that calculate difference between pixel values and their neighbouring pixels to a distance of n pixels.