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I want to determine the temperature of burning coal particles using two colour-pyrometry (analysis of the color channels in the pixles). That is why I need to have very specific information about how the camera saves the images in the formats .raw .dng and .tiff (considering the 8bit adn 16bit versions of tiff) in order to be able to employ the data in matlab.

Using the function imfinfo() in matlab for the 8bit tiff files displayed the following information:

Format: 'tif'-------
FormatVersion: []-------
Width: 512-------
Height: 512-------
BitDepth: 24-------
ColorType: 'truecolor'-------
FormatSignature: [73 73 42 0]-------
ByteOrder: 'little-endian'-------
NewSubFileType: 0-------
BitsPerSample: [8 8 8]-------
Compression: 'Uncompressed'-------
PhotometricInterpretation: 'RGB'-------
StripOffsets: 298-------
SamplesPerPixel: 3-------
GrayResponseUnit: 0.0100-------
MaxSampleValue: [255 255 255]-------
MinSampleValue: [0 0 0]-------
Thresholding: 1-------
Offset: 8-------

To this information I have the following questions:

  1. Do the MaxSampleValue: [255 255 255] and the MinSampleValue: [0 0 0] represent the black and saturation level? And if so, then what does the offset of 8 represent exactly?
  2. As there is no information about a linearization table, I assume that there hasn't been any non-linear transformation applied to the sensor data for storage purposes. So is it safe to assume that the data in the tiff file is linear?
  3. The image I read in is a 512x512x3 uint8 file. And since the documentation shows that it is a truecolor image, I assume the first matrix is the red one, the second is green and the third is blue. Is this correct?
  4. Has there been any image processing steps applied to the tiff files? I.e. gamma correction or white balancing?
Mark Setchell
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matchacamel
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  • I think you need to specify which camera you are using... – Mark Setchell Jul 04 '16 at 12:05
  • I'm using a Phantom v.4.3 – matchacamel Jul 04 '16 at 12:07
  • Do you have a link to its specification? – Mark Setchell Jul 04 '16 at 12:10
  • No, it is a legacy camera which means it is no longer being produced and there is no information about it on the producer's website. But it's the only high speed camera available in my department's lab at universitiy. I tried contactig the producer but didn't get any help. This is a link to a similar more modern camera https://www.phantomhighspeed.com/Products/v-Series-Cameras/v411 – matchacamel Jul 04 '16 at 12:15
  • The camera I am using also has an RGB CMOS sensor – matchacamel Jul 04 '16 at 12:16
  • [this](http://partners.adobe.com/public/developer/en/tiff/TIFF6.pdf) migth help. It specifies the Fields of a tif Info – marco wassmer Jul 04 '16 at 12:23
  • did you consider contacting the manufacturer? I'm sure they will provide you with information even on legacy products. why don't you use the provided raw data instead of thinking about how they might have manipulated the tiff files? – Piglet Jul 04 '16 at 14:18

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