Camera response curve - Revision history

Erik Krause: typo

2007-11-23T22:13:03Z

typo

Erik Krause: typo in template call

2007-11-23T22:11:38Z

typo in template call

Erik Krause: basic page

2007-11-20T15:48:36Z

basic page

New page

The '''camera response curve''' is {{Glossary|a curve showing the relation between amount of incoming light and image pixel values of a digital camera.|1}

This curve is sometimes also called '''Opto-Electrical Transfer Function'''.

Although optical sensors work quite linear (a certain amount of photons coming in causes a proportional amount of electrons in the sensor cell), the resulting pixel values are not proportional to the amount of incoming light. This might have several reasons:
* The analog-digital converter might not work linearly.
* A [[Gamma]] correction is applied.
* A correction is applied to make the image more visually appealing
* A white balance is applied to compensate for different light temperature

While the first reason applies to all kinds of images, the other ones apply to non-RAW ([[JPEG]], [[TIFF]])) images only. [[RAW]] images should contain linear sensor data.

The '''camera response curve''' is an issue mainly in [[HDR]] generation where it is necessary to have linear (proportional to light) input data. Non-linear data (= a badly estimated camera response curve) will result in banding in contrast gradients (f.e. around bright lights).

← Older revision		Revision as of 22:11, 23 November 2007
Line 1:		Line 1:
−	The '''camera response curve''' is {{Glossary\|a curve showing the relation between amount of incoming light and image pixel values of a digital camera.\|1}	+	The '''camera response curve''' is {{Glossary\|a curve showing the relation between amount of incoming light and image pixel values of a digital camera.\|1}}

	This curve is sometimes also called '''Opto-Electrical Transfer Function'''.		This curve is sometimes also called '''Opto-Electrical Transfer Function'''.

@@ Line 9: / Line 9: @@
 * A white balance is applied to compensate for different light temperature
-While the first reason applies to all kinds of images, the other ones apply to non-RAW ([[JPEG]], [[TIFF]])) images only. [[RAW]] images should contain linear sensor data.
+While the first reason applies to all kinds of images, the other ones apply to non-RAW ([[JPEG]], [[TIFF]]) images only. [[RAW]] images should contain linear sensor data.
 The '''camera response curve''' is an issue mainly in [[HDR]] generation where it is necessary to have linear (proportional to light) input data. Non-linear data (= a badly estimated camera response curve) will result in banding in contrast gradients (f.e. around bright lights).