Panorama Software - Panoweaver 5.00 HDR image
How to Get Panoramic HDR Image with Panoweaver 5.00
HDR is abbreviation for High Dynamic Range. For a scene, dynamic range refers to ratio between the brightest and darkest parts of the scene. The Dynamic Range of real-world scenes can be quite high - ratios of 100,000:1 are common in the natural world. An HDR image stores pixel values that span the whole tonal range of real-world scenes.
Dynamic range of JPEG format image won't exceed 255:1, so it is considered as LDR (Low Dynamic Range). Similarly, dynamic range of CRT monitor won't exceed 100:1. While HDR image (image of 32bit/color channel) shows the dynamic range of real world (natural dynamic range is generally considered to be 100,000:1; the dynamic range human eyes can identify is around 100,000:1), which is much higher than that of standard display equipment and images shot with common camera. As a result, HDR image cannot be displayed with this equipment. So from broad sense, image with dynamic range of higher than 255:1 (8 bit per cooler channel) is regarded as HDR image.
Image bit and dynamic range
There are two methods to show image bit. One is bits/color channel; the other is bits/pixel. For RGB images, each pixel contains 3 color channels - R, G, B. Image bit has the following relation with dynamic range (lightness ratio):
|
Type of digital support |
Bit depth per color channel |
Bit depth per pixel |
Maximum dynamic Range |
Note |
|
JPEG or 8-bit TIFF |
8 |
24 |
255:1 |
256=28 |
|
12-bit CCD |
12 |
36 |
4,096:1 |
|
|
14-bit CCD |
14 |
42 |
16,384:1 |
|
|
16-bit TIFF |
16 |
48 |
65,536:1 |
"Real" maximum limited by dynamic range of capturing device |
|
HDR image (e.g. Radiance RGBE format) |
32 |
96 |
infinite |
"Real" maximum limited by the captured dynamic range |
When you take a picture inside of a room, the bright windows always get dazzling white since the camera and display are simply incapable of displaying the luminosities in the real world. While HDR images captures wider color range, which helps photographers get better images, solving the over exposure and under exposure problem in photography, especially digital photography. For some users, they can save the 32 bit HDR as well and make some further editing.
Let's see the traditional troublesome way to solve the over/ under exposure problem first.
1. Shoot fisheye images to create a panorama.
2. Take an extra image in the direction of the over exposure window at an appropriate EV which allows users to see the window through clearly.
3. Use Photoshop to take out the window area and make a mend in the panoramic image got in 1st step. After all the heavy work, then you will get a panoramic image of good result. See below.
You have to spend hours for every panoramic image with the method above. While with HDR, you can get a good result image without troublesome work. Panoweaver 5.00 automatically makes an HDR image, which stores wider luminosity range than that can be displayed. You can simply adjust on the HDR image in the software and get a perfect image quickly. Below is an image converted directly from HDR without any other editing work. Please refer to How to Get HDR Image for details of generating HDR with Panoweaver 5.00.
How to get HDR panoramic image with Panoweaver 5.00?
There are two methods. One is to import Camera Raw file and to stitch it into 16 bit panoramic image. The other is to get HDR image from bracket exposure, that is, to shoot several groups of fisheye images of different exposure value, stitch them separately and then combine them to get HDR image.
