Compression Service

Description

Compression Service: The Compression Service supports delayed, lossless compression of received images. This is an alternative to immediately compressing images when received. (The lossless compression rules are configured by the CompressionRules attribute in the StorageSCP service.) The value of the MaxConcurrentCodec attribute in the Compression Service also effects the on-the-fly compression and decompression during the receive and retrieve of images by the StorageSCP and QueryRetrieveSCP services. (For details, see the MaxConcurrentCodec attribute below.) Also see the CODECs page in the dcm4che14 documentation.

Attributes

MaxConcurrentCodec

Maximum number of concurrent tasks for compressing and decompressing images. When the default value is of MaxConcurrentCodec is 1, all compression and decompression operations are serialized. For example, if on-the-fly compression during an image receive is activated, and three modalities concurrently send uncompressed images to the archive, only one image received from one modality is compressed at the same time. This significantly reduces the receiving performance. The used codec allocates memory for uncompressed pixel data of at least one frame, so without limiting the maximum number of concurrent compression tasks, memory consumption could become unacceptable. You will receive an out of memory error if the memory consumption exceeds the configured -Xmx value in the dcm4chee_home/bin/run.conf file).

TaskInterval

Interval in which the database is checked for images to compress. Format:

interval!from-to or NEVER
- interval = ##s (in seconds), ##m (in minutes), ##h (in hours).
- from = start hour (0-23) when no compression should be performed to = end hour (0-23) when no compression should be performed
- NEVER = disable automatic compression
Example: 10s!9-17 means every 10 seconds, poll the database and check for images to compress, except between the hours of 9:00am and 5:00pm. By setting this type of TaskInterval, you can ensure compression of images happens outside of peak imaging hours.

LimitNumberOfFilesPerTask

Maximum number of files that are compressed in one task.

CompressionRules

Specifies compression rules and delay for individual SOP Classes. Format:

sop-class-name-or-uid:compression:delay** sop-class-name-or-uid = the UID of the SOP class, or a string name defined in the dictionary.xml file under uids type="SOPClass"
- compression = JPLL|JLSL|J2KR
- JPLL -JPEG lossless
- JLSL - JPEG-LS lossless
- J2KR - JPEG 2000 lossless
- delay = ##d (in days)
Example:
- ComputedRadiographyImageStorage:JLSL:5d means for the Computed Radiography Image Storage SOP class, compress with JPEG-LS lossless compression every 5 days.

VerifyCompression

Enables the verification of the compressed file.

TempDirectory

Directory used to spool decompressed files for compression verification. Relative path names are resolved relative to dcm4chee_home/server/default/.

KeepTempFileIfVerificationFails

Defines how long files that were decompressed for verification remain for further analysis before being deleted, if the decompressed pixel data differs from the pixel data in the original file. Format:

##m (in minutes), ##h (in hours), ##d (in days)

FileSystemMgtName

Used internally. Do not modify.

BufferSize

Size of write byte buffer.

Name

The class name of the MBean

State

The status of the MBean

StateString

The status of the MBean in text form

Operations

create

Standard MBean lifecycle method

start

The start lifecycle operation

stop

The stop lifecycle operation

destroy

The destroy lifecycle operation

jbossInternalLifecycle

The detyped lifecycle operation (for internal use only)

checkForTempFilesToDelete

Check for temporary image files to delete.

checkForFilesToCompress

Check for files to compress.

compress

Compress specified object if it is uncompressed and if there is a Compression Rule for its SOP Class UID configured