2. Data Files and Formats
:
2.3 Standard File Formats
: 2.3.3 Image Files (.pif and .png)
2.3.3
Image Files (.pif and .png)
Image data from the GS FLX+ Instrument are stored as compressed industry-standard .png image files (
http://www.w3.org/TR/PNG/
).
The PNG format allows metadata to be included in each image file for ease of access. Currently, the image data from the GS FLX+ Instrument replicates the following annotations found in the imageLog.parse file.
PNG File Annotation
Example
Title
:454 Genome Sequencer camera image
Description
:Image X of Y for flow apyrase for Run R_xxx
Creation Time
:24 01 2011 20:51:26 GMT
Software
:2.6 (20110120_1556)
Source
:camera model 806 serial 591
Host
:FLX08100646
Run
:R_2011_01_24_15_24_20_FLX08100646_A…
Exposures
:1634
Exposure
:11
Flow
:apyrase08
Exposure Time (ms)
:36000
Exposure Complete Time (sec)
:1295902285.041494
DC Offset
:495
Camera Model
:806
Camera Serial
:591
CCD Temperature (C)
:-025.05
PTP ID
:749558
Table 7: PNG File Metadata
The legacy .pif image format is still supported, so older Run image data (and data from GS Junior Instrument Runs) can be used directly, without re-processing. The header is 12 bytes long, comprised of three 4-byte integers: the first integer value is the number of bits per pixel of data; the second integer is the width of the image in pixels; and the third integer is the height of the image in pixels. The following data in the file are the pixel intensity values, presented in row major order starting in the upper left corner. Currently, all image data is stored in 16 bit unsigned integers, or 2 bytes per pixel. Valid image data is limited to the first 14 bits.
