Posted by
Ye Chen on
Sep 13, 2005; 7:09pm
URL: http://imagej.273.s1.nabble.com/Information-regarding-formats-tp3704893p3704894.html
Where you get your original bmp images? Your should use your original
application software to save your images as 8 bit color image or called
indexed image. Not save them as RGB image. If you save your images as 8 bit
color (indexed images), your image still shows color but with a look up
table. When you use imageJ to open them and convert to grayscale, the pixel
value won't change, it only discards the look up table. On the other hand,
if you save your images as RGB image, the image doesn't save your original
pixel value, it saves only the color information represented by R,G,B
value. When you use ImageJ to convert RGB image to a grayscale, it just
apply (R+G+B)/3 to each pixel, the pixel value maybe not the same as your
original image pixel value so it may not make sense to you at all.
Hope this will help
Ye Chen
At 01:05 PM 9/13/2005, you wrote:
>Please, could anybody in the list indicate some online source of
>information regarding conversion between graphic types?
>
>My problem is that, to make some measurments, I need to open a series of
>bmp images (as a stack) with RGB color format and convert to
>grayscale-stack manageable format. I do it but...the new pixel values are
>absolutely no sense for me. Even the original RGB values (three values, of
>course) are not useful. However, the original application (Metafluor
>Analyst) shows the original RGB values as one single value. Therefore, I
>think some learning about the maths involved in image coinversion could help me
>
>Thanks