Image bit depth values.

Question

REPHRASED QUESTION:

I am coming up with a list of possible image bit depth values that could be used as a predefined reference list in my application. I could think of 8,16,24 and 32 bit depths. The image formats considered are BMP, JPEG, PNG and GIF.

I understand the bit depth decides the quality and thereby the storage requirements for the image. The application is used to store user uploaded images(non-medical, non-DICOM).

Are there more bit depths other than the ones mentioned above that i should be including in my list? Are there any stats on the usage of the images with bit depths?

Appreciate your response!

Answer 1

24 bits is considered full color, meaning every color you can see can be represented in the image. 32 bits adds an element of transparency, so that the background can partially show through the image. 8 and 16 bit images use a smaller number of colors, which might be acceptable or might not depending on the image and the color selection algorithm.

There are many other considerations for choosing a graphics format, but as you didn't ask that question I won't address them.

Answer 2

This is a more complicated question than you might think. Bit depth can mean either the number of bits per pixel or it could be the number of bits per channel within the pixel. The meaning of the channels can vary. For example, 32 bits can give you rgb with a waste byte or rgba or cmyk with 8 bits per channel. 16 bits can give you gray, gray-alpha, or 5 bits each rgb and 1 bit alpha (or no alpha).

Dicom files in particular may have oddball bits per channel, including 10, 11, and 12 and may go up to 32 bits per channel.

16 bit per channel is becoming more common, so you might see 48 bit rgb or 64 bit rgba or 64 bit cmyk.

Shameless plug: my company, Atalasoft, put out an e-course on imaging and the first lesson does a good job explaining a lot of the vocabulary and capabilities of various imaging and codecs.

Answer 3

Given that you have such a short list of formats, you ought to just look at the definitions of the formats to see what you need to support.

PNG is probably the most complex, supporting bit depths from 1 to 16 bits per channel, palettized images, alpha channel, transparent colors, etc.

For what it's worth, almost no software out there supports the full PNG format spec...

Answer 4

I need to image dicom bits depth 8 (255 gray scales),if you able ,