This invention relates to the field of medical instrument involving an accurate and simple measurement for ECG (Electrocardiography) on multi-touch screens based on a multi-touch on a display screen.
The terminologies are used in this invention as following:
Gesture: The finger touch actions on screen, like single point touch, touch slice, 2 points pinch (this is the one used in this invention), multi touches spin;
API: Application Programming Interface;
iOS: iOS is the operation system of Apple, run on Apple's mobile devices like iPhone, iPad;
The traditional ECG measurement is that doctors use the dividers to lock 2 points on ECG (on paper), and move the dividers on the standard ECG ruler to read the intervals between two points;
Alternativly,the ECG ruler (or other similar tool)is used to measure ECG directly on the display screens.
Disadvanges of the Traditional Methods:
On non-touch screen devices like PC screen, the measurement of ECG with PC mouse is utilized in the prior art which clicks on the initial point, drags mouse to the next point, then calculates.
The patent application (CN 200710092530.3) tiltled as “Approach of ECG measurement” discloses an ECG measurement approach which displays ECG waves on the screens, then determines the unit convert factor. After numberious of clickings on the wave top point, wave beginning and wave ending points with PC mouse, all clicked point coordinates are saved and calculated. The present invention discloses a method to use touch screen which replaces the clicks with PC mouse which does not use the screen touch feature for ECG measurement.
Neither the traditional measure approach using rulers, nor the mouse clicking and draging based approach, is user-friendly to yield accurate measurement for ECG.
In the prior art, there is no similar application on touch-screen devices as disclosed in the present invention, while the traditional mouse based approach can be not applied for the widely used touch screen devices in the field of ECG measurement. The present invention reveals a novel process of ECG measurement with a touch screen device.
The subject of the invention is to implement a novel process to measure ECG waves with a touch screen device by using multi-touch feature, which can yield horizontal interval and vertical interval between two touch points. This approach solves a long-desired problem which the ECG waves cannot be accurately measured with traditional approaches on display screens.
To implement the approach by using multi touches on screen comprises the following steps:
According to above steps of the measurement, the projected target points are based on the actual touch point coordinates on the screen, which is read with a gesture API provided by an operation system of a touch screen device.
According to the step 2 of above process of measurement of ECG, the way to get the target measurement points is that the assumed (x1, y1) and (x2, y2) are the 2 actual touch point coordinates, x1 and x2 are divided by pixelsPerPoint (pixels per point on screen), get n1 and n2 as the point index, respectively, through which we can read the voltage value on the y axis from the array voltage[ ]: v1 and v2 . Coordinates (n1, v1 ) and (n2, v2 ) are the target points projected on x axis and y axis. The two target points are drawn on the screen, we shall convert them into the pixels per point.
According to the step 3 of above process of measurement of ECG, the x interval and y interval are calculated as following:
X interval is ((n2−n1)/sample)×1000
According to the step 4 of above process of measurement of ECG, the measurement is synchronously performed while the finger touch points are moved.
This invention further discloses the specific steps to implement the approach on an iOS device. The API is UIPinchGestureRecognizer class in iOS. The two actual touch point coordinates on screen are generated by UIPinchGestureRecognizer:
Following equations are used to calculate x1 and x2 wherrein x1 is a left point:
Int x1=self.touch1.x>=self.touch2.x?self.touch2.x: self.touch1.x;
int x2=self.touch1.x<=self.touch2.x?self.touch2.x: self.touch1.x;
The index of points are calculated with the ECG wave data (array):
int n1=Math.Floor(x1/pixelsPerPoint);
int n2=Math.Floor(x2/pixelsPerPoint);
The voltage values are calculated with the voltage[ ] array:
int v1=voltage[n1]
int v2=voltage[n2];
The following functions are used to draw the points and lines:
The major advantage of this invention is a very user-friendly method (touch screen using fingers and move) for users. The measurement of ECG waves is accurate and easy to perform.
The process of the present invention is applicable to other similar measurement, such as Brain Waves (electroencephalography), or other waves when the voltage is on y axis and time is on x axis.
To make the invention more understandable, here is a detailed description for an example to explain how to implement the invention.
Implementation Details:
Multi-touch screen devices (such as iPad) can provide a series of gesture API, and the API application is able to acquire the finger touch data (coordinates) and the event when the finger touches and slices.
Inputs are:
Assumed (x1, y1) and (x2, y2) are the two actual touch point coordinates, and the following parameters are predefined:
x1 and x2 were divided by pixelsPerPoint (pixels per point on screen) which yielded n1 and n2 as the point index, respectively, through which we could read the voltage values as v1 and v2 on the y axis from the array voltage[ ]. Coordinates (n1, v1 ) and (n2, v2 ) were the target points projected on x axis and y axis.
The two target points, which were converted into the pixels per point, were drawn on the screen.
Outputs were:
The x interval in milliseconds and y interval in microvolt were calculated by
x=((n2−n1)/sample)×1000,
y=v2−v1.
When users moved the touch figures (one or both) on the screen, the calculation was performed synchronously and the results of measurement were shown in real time. The approach of present invention can potentially improve the measurement efficiency and accuracy.
The iOS was taken as an eample, the following was a detailed description to implement the approach of present invention.
iOS provides a series of gesture API to capture the finger touches and movement events, the most of API being used is UIPinchGestureRecognizer class. UIPinchGestureRecognizer is a sub class that targets to pinch gestures on the screen. When two points were touched, an instance of UIPinchGestureRecognizer class was created, and the two actual touch point coordinates on screen were generated by this instance:
numberOfTouches: Number of Touches;
locationOfTouch(int index): Coordinate of the touch index of index.
Followings were equations for calculating x1 and x2 (x1 is the relative left point):
Int x1=self.touch1.x>=self.touch2.x?self.touch2.x: self.touch1.x;
int x2=self.touch1.x<=self.touch2.x?self.touch2.x: self.touch1.x.
The index of the point was calculated with the ECG wave data (array):
int n1=Math.Floor(x1/pixelsPerPoint);
int n2=Math.Floor(x2/pixelsPerPoint).
The voltage values were calculated with the voltage[ ] array:
int v1=voltage[n1];
int v2=voltage[n2].
The following functions were used to draw the points and lines:
Above are examples to explain how to implement the invention, which helps to illustrate the subject of the invention, the solution and advantages thereof. An important point to declare is that above description is only an example of the invention, not include all about the invention. And any technologies derived from the invention, equivalent replacements and improvements are all covered in the claimed range of the invention.
Number | Name | Date | Kind |
---|---|---|---|
20110150291 | Jung | Jun 2011 | A1 |
Entry |
---|
Saxon LA, Smith A, Doshi S, Dinsdale J, Albert D. iPhone Rhythm Strip—The Implications of Wireless and Ubiquitous Heart Rate Monitoring. J Am Coll Cardiol. 2012;59(13s1):E726. |
BIOPAC Systems, Inc. AS148—Automated ECG Analysis. 2006;pp. 1-7. |
Number | Date | Country | |
---|---|---|---|
20140148719 A1 | May 2014 | US |