Nowadays, commercially available digital cameras arewidely used to measure a color 1, 2.The purpose of this document is to documentthe practical assignment for an imaging measurement with an imaging setup characterizedor calibrated for the measurement task. During this measurement, few aspectscan be understood:a) Measuring equipmentb) Object that we need to measurec) Describing the purpose what kindcharacteristics we have found.1.
Methodology Every device depends on different colormodels to display color. Input devices – your camera and or computer outputdevices (monitors or screens) – use the additive color model to display color.They start with darkness and add red, green, and blue light to create aspectrum of colors. Printers, on the other hand, use the subtractive colormodel. They start with white and using opposing colors – cyan, magenta, andyellow – to subtract color 4. In our methods, we have used the standard color chart; the X-rite Color-Checker24-color “normal” version was used.
Mostly, the digital cameras arebeing used in RAW mode and after that we need to convert these RAW files to anuncompressed 24-bit format with the help 8-bit on each channel RGBs color spaceby computer programs which is normally provided by manufacturers. The RGBscolor space was defined by the International Electro-technical Commission (IEC)3. Weadopted the RGBs because it is one of the most common color spaces in theimaging products and almost all digital cameras on the market have the RGBscolor space mode.
You can see the digital cameras list used in the measurementscan be seen in Table given below: No. Name Manufacturer and model Lens Image sensor Image Size The processof the image correction method applied for each camera is as follows: 1) Taking the uniform photo or image2) Take photos of a sample with theColorChecker 24-color chart (size: 60 x 90 mm) and 140 colors under the sameillumination condition of Step 1. As a sample, another ColorChecker chart wasused.
3) Perform the shading corrections forphotos of Step 2 using the coefficients derived in step 1.4) Calculating the color correctionvalues5)Apply the color correction values derive at Step 4 to all pixels of photos ofStep 3. Duringthe step 5, the color corrected image files in the RGBs space are obtained.Conversion equations between sRGB and the tristimulus values are defined inRef.
3. Then, the color data can be converted to any color space attributes.We converted the sample data to the CIE 1976 L*a*b* color space for discussion.