Method and system for colour calibration using a barcode
A system and method for performing color calibration using barcodes with colored subunits. The barcode can be decoded in a conventional way and the colors of the subunits can be used for color calibration.
1. A method carried out by a computer to generate a color calibration look-up-table (LUT) using a barcode image for an image sensor to achieve a target behaviour, said barcode comprising encoded data in subunits of the barcode and wherein at least one subunit of the subunits of the barcode has a color point representing a calibration pattern, and wherein the target behaviour of the image sensor is defined by target digital sensor values, the method comprising the steps of:
receiving a digital image of the barcode acquired with the image sensor, the digital image being stored with one or more received digital sensor values,
for each of the at least one subunit of the subunits representing the calibration pattern and having the color point, wherein the encoded data includes metadata having information related to the color point of the calibration pattern, wherein the information includes a target digital sensor value and a location of each color point in the barcode in (x,y) coordinates,
retrieving one value of the received digital sensor values,
obtaining the target digital sensor value for the image sensor corresponding to the color point of the calibration pattern,
calculating the difference between the received digital sensor value and the obtained target digital sensor value of the image sensor for the color point of the calibration pattern, and
creating a calibration LUT of the image sensor for adjusting the received digital sensor values of the color point based on the calculated difference to calibrate the image sensor to acquire an image based on the color point of the calibration pattern.
2. The method according to claim 1 , wherein n subunits have the color of a color point of a color chart.
3. The method according to claim 2 , wherein subunits having the same color point are not adjacent.
4. The method according to claim 1 , wherein a dedicated location of the barcode is used to provide the encoded data related to the color chart of the barcode.
5. The method according to claim 1 , comprising a non-volatile memory, wherein a target DSV or DDL is/are available from at least one of the non-volatile memory or the barcode.
6. The method according to claim 1 , comprising a user menu, wherein a target DSV or DDL is/are available from the user menu.
7. A non-transient signal storage medium storing a computer program product, which, when executed on a processing engine, carries out the method of claim 1 .
8. An imaging device comprising an image sensor and a display to display images acquired with the image sensor, said imaging device further comprising the non-transient signal storage medium of claim 7 for calibrating the display of the imaging device.
9. The imaging device according to claim 8 , wherein the imaging device is a dermatoscope.
10. A data processing system for generating a color calibration look-up-table (LUT) having a barcode image for an image sensor to achieve a target behaviour, said barcode comprising encoded data in subunits of the barcode and wherein at least one subunit of the subunits of the barcode has a color point representing a calibration pattern, and wherein the target behaviour of the image sensor is defined by target digital sensor values,
the system comprising:
a receiver for receiving a digital image of the barcode acquired with the image sensor, the digital image being stored with one or more received digital sensor values, for each of the at least one subunit of the subunits representing the calibration pattern and having the color point, wherein the encoded data includes metadata having information related to the color point of the calibration pattern, wherein the information includes a target digital sensor value and a location of each color point in the barcode in (x,y) coordinates,
means for retrieving a received digital sensor value,
means for obtaining the target digital sensor value for the image sensor corresponding to the color point of the calibration pattern,
a calculator for calculating the difference between the received digital sensor value and the obtained target digital sensor value of the image sensor for the color point of the calibration pattern, and
a calibration LUT of the image sensor and means for adjusting received digital sensor values of the color point based on the calculated difference to calibrate the image sensor to acquire an image based on the color point of the calibration pattern.
11. The data processing system according to claim 10 , wherein n subunits have the color of a color point of the color chart.
12. The data processing system according to claim 11 , wherein subunits having the same color are not adjacent to each other.
13. The data processing system according to claim 10 , wherein a dedicated location of the barcode provides the encoded data related to the color chart of the barcode to indicate which type of color chart is provided.
14. The data processing system according to claim 10 , comprising a non-volatile memory, wherein a target DSV and/or DDL is/are available from at least one of the non-volatile memory and the barcode.
15. The data processing system according to claim 10 , comprising a user menu, wherein target DSV and/or DDL is/are available from the user menu.
16. The data processing system according to claim 10 , comprising an imaging device, said imaging device comprising a display and an image sensor, the data processing system being further adapted to calibrate the display of the imaging device.