On Wed, Jan 05, 2022 at 03:19:12PM +0100, Karsten Hilbert wrote: > > You may want to give CLAHE (Contrast Limited Adaptive Histogram > > Equalization) a try. > > > > It's implemented in OpenCV. > > For what it's worth, here's code which so does:
Some updates: - Using various OpenCV recipes or interactive tools like gimp, it's turning out to be hard to figure out exact processing needed. Most probably it's multiple such operations in a sequence. - Tried neural network. It kind of works, but given the nature of data, there is no margin for error. Also it's a brute force approach. Tried just for the sake of it. - Will possibly try an LUT now. Again not very elegant, but might be more accurate than neural net and less costly. But not sure, whether across images the lookup table would be uniform or not. - Experimented with the relation between raw pixel value and vendor's final image. It becomes a function when 2 adjacent pixels (overall 9x9) matrix are considered together. But this was studied on only 1 image. - Will need more images. Gathering raw data from usbmon every time will take a lot of time. Instead, found that the vendor software provides a way to export the raw image. This makes it easy to gather several images for study. - Using pydicom package, found several details from the dicom header, placed by the vendor software. Please do have a look at a sample header attached. If you find any fields that may give any hints about the calibration or post processing that the vendor software applies, please do highlight. -- Mayuresh
Dataset.file_meta ------------------------------- (0002, 0000) File Meta Information Group Length UL: 182 (0002, 0001) File Meta Information Version OB: b'\x00\x01' (0002, 0002) Media Storage SOP Class UID UI: Digital Intra-Oral X-Ray Image Storage - For Processing (0002, 0003) Media Storage SOP Instance UID UI: 1.2.250.1.90.3.2561937961.1609603392.484 (0002, 0010) Transfer Syntax UID UI: JPEG Lossless, Non-Hierarchical, First-Order Prediction (Process 14 [Selection Value 1]) (0002, 0012) Implementation Class UID UI: 1.2.250.1.90.50.6.14.7.3 (0002, 0013) Implementation Version Name SH: 'TW_6_14_7_3' ------------------------------------------------- (0008, 0005) Specific Character Set CS: 'ISO_IR 100' (0008, 0008) Image Type CS: ['ORIGINAL', 'PRIMARY'] (0008, 0016) SOP Class UID UI: Digital Intra-Oral X-Ray Image Storage - For Processing (0008, 0018) SOP Instance UID UI: 1.2.250.1.90.3.2561937961.1609603392.484 (0008, 0020) Study Date DA: '20210102' (0008, 0021) Series Date DA: '20210102' (0008, 0022) Acquisition Date DA: '20210102' (0008, 0023) Content Date DA: '20210102' (0008, 0030) Study Time TM: '170055' (0008, 0031) Series Time TM: '170312' (0008, 0032) Acquisition Time TM: '170312' (0008, 0033) Content Time TM: '170312' (0008, 0050) Accession Number SH: '' (0008, 0060) Modality CS: 'IO' (0008, 0068) Presentation Intent Type CS: 'FOR PROCESSING' (0008, 0070) Manufacturer LO: 'Carestream-Trophy' (0008, 0080) Institution Name LO: '' (0008, 0090) Referring Physician's Name PN: 'winxp' (0008, 1030) Study Description LO: '' (0008, 1050) Performing Physician's Name PN: 'winxp' (0008, 1052) Performing Physician Identification Sequence 0 item(s) ---- (0008, 1090) Manufacturer's Model Name LO: 'RVG 5200' (0008, 2218) Anatomic Region Sequence 1 item(s) ---- (0008, 0100) Code Value SH: 'T-11170' (0008, 0102) Coding Scheme Designator SH: 'SNM3' (0008, 0104) Code Meaning LO: 'Maxilla' --------- (0008, 2228) Primary Anatomic Structure Sequence 1 item(s) ---- (0008, 0100) Code Value SH: 'T-54210' (0008, 0102) Coding Scheme Designator SH: 'SNM3' (0008, 0104) Code Meaning LO: 'Maxillary right third molar tooth' --------- (0009, 0011) Private Creator LO: 'TROPHY' (0009, 1105) Private tag data DS: '6.14.7.3' (0009, 1109) Private tag data UL: 0 (0009, 110a) Private tag data UL: 1983368088 (0009, 1111) Private tag data US: 3 (0009, 1112) Private tag data SL: 0 (0009, 1115) Private tag data US: 0 (0009, 1117) Private tag data SL: 0 (0009, 1118) Private tag data SL: 0 (0009, 1119) Private tag data SL: 0 (0009, 111a) Private tag data CS: '00' (0009, 111b) Private tag data DS: [0.019, 0.019] (0009, 1131) Private tag data US: 1 (0009, 1133) Private tag data US: 96 (0009, 1134) Private tag data US: 4095 (0009, 11b0) Private tag data 1 item(s) ---- (0009, 0011) Private Creator LO: 'TROPHY' (0009, 11b1) Private tag data CS: 'SHARPNESS' (0009, 11b2) Private tag data US: 4 (0009, 11b3) Private tag data SS: 3 --------- (0010, 0010) Patient's Name PN: 'XXXXXXXXXXXXXXXXXXX' (0010, 0020) Patient ID LO: '7967857769788483927579686575926866926546828671926548484848484854' (0010, 0030) Patient's Birth Date DA: '19000101' (0010, 0040) Patient's Sex CS: 'O' (0018, 1000) Device Serial Number LO: 'DJJC0023' (0018, 1020) Software Versions LO: 'TW 6.14.7.3' (0018, 1050) Spatial Resolution DS: "20.0" (0018, 1164) Imager Pixel Spacing DS: [0.019000, 0.019000] (0018, 1200) Date of Last Calibration DA: '20151002' (0018, 1201) Time of Last Calibration TM: '000000' (0018, 1401) Acquisition Device Processing Code LO: '17' (0018, 1508) Positioner Type CS: 'NONE' (0018, 1510) Positioner Primary Angle DS: "0.0" (0018, 7004) Detector Type CS: 'SCINTILLATOR' (0018, 700a) Detector ID SH: '' (0018, 702a) Detector Manufacturer Name LO: 'Carestream-Trophy' (0018, 702b) Detector Manufacturer's Model Name LO: '' (0018, 7030) Field of View Origin DS: [0, 0] (0018, 7032) Field of View Rotation DS: "90.0" (0018, 7034) Field of View Horizontal Flip CS: 'NO' (0020, 000d) Study Instance UID UI: 1.2.250.1.90.1.2561937961.1609603255.906 (0020, 000e) Series Instance UID UI: 1.2.250.1.90.2.2561937961.1609603392.484 (0020, 0010) Study ID SH: '' (0020, 0011) Series Number IS: "1" (0020, 0013) Instance Number IS: "1" (0020, 0020) Patient Orientation CS: ['A', 'F'] (0020, 0062) Image Laterality CS: 'R' (0020, 4000) Image Comments LT: '' (0028, 0002) Samples per Pixel US: 1 (0028, 0004) Photometric Interpretation CS: 'MONOCHROME2' (0028, 0010) Rows US: 1168 (0028, 0011) Columns US: 1562 (0028, 0030) Pixel Spacing DS: [0.019000, 0.019000] (0028, 0100) Bits Allocated US: 16 (0028, 0101) Bits Stored US: 12 (0028, 0102) High Bit US: 11 (0028, 0103) Pixel Representation US: 0 (0028, 0301) Burned In Annotation CS: 'NO' (0028, 1040) Pixel Intensity Relationship CS: 'LIN' (0028, 1041) Pixel Intensity Relationship Sign SS: -1 (0028, 1052) Rescale Intercept DS: "0.0" (0028, 1053) Rescale Slope DS: "1.0" (0028, 1054) Rescale Type LO: 'US' (0028, 2110) Lossy Image Compression CS: '00' (0040, 0555) Acquisition Context Sequence 0 item(s) ---- (0088, 0200) Icon Image Sequence 1 item(s) ---- (0028, 0002) Samples per Pixel US: 1 (0028, 0004) Photometric Interpretation CS: 'MONOCHROME2' (0028, 0010) Rows US: 116 (0028, 0011) Columns US: 156 (0028, 0100) Bits Allocated US: 8 (0028, 0101) Bits Stored US: 8 (0028, 0102) High Bit US: 7 (0028, 0103) Pixel Representation US: 0 (7fe0, 0010) Pixel Data OB: Array of 18096 elements --------- (2050, 0020) Presentation LUT Shape CS: 'IDENTITY' (7fe0, 0010) Pixel Data OB: Array of 1371108 elements
