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Topics - Phogi

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1
General / Undistort images using the pre-calibration file
« on: September 07, 2022, 04:15:31 PM »
Hi mates,

As Metashape can load the dewarp parameters from P4R EXIF, is there a way to undistort the images using the pre-calibration loaded in before align?

Thanks!

2
Hi Alexey,

I'm using Metashape v1.8 and I found this is a bug in exporting dense point cloud (laz for example) in GDA2020 / MGA to WGS84.

As in Metashape WKT:
'GEOGCS["GDA2020",DATUM["Geocentric Datum of Australia 2020",SPHEROID["GRS 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],TOWGS84[0,0,0,0,0,0,0],AUTHORITY["EPSG","1168"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9102"]],AUTHORITY["EPSG","7844"]]'

GDA2020 should be same as WGS84 which makes sense for the moden applications, and it does so when converting in Metashape, but when exporting, the WGS84 or WGS84/UTM zone 55 file will have a shift compared to GDA2020, and it is not the same as GDA94 as well.

Please have a look, thank you!!!

Best,

3
Hi everyone,

I searched on the forum and found there are two ways to reproject 3D points into 2D image pixels, one is from sensor.calibration, the other is from camera.project. What is the difference between them? Furthermore how does the pixels count, from topleft corner or they've been shifted from center + cx/cy?

Could anyone help with how does camera.project works? The reason is I want to check why some markers are having higher pixel errors when they do align fine, if there's anything abnormal in the camera matrix or projection matrix, but how can I retrieve this info?

Thanks in advance!


4
Hi Alexey,

I am looking at the chunk.point_cloud.meta and saw the key point limit is 80,000 while in GUI I was specifying as 40,000, and the MatchPhotos/tiepoint_limit is also doubled from API, is that an expected result?

My other question is could you share for camera's projection matrix and this point_cloud.cov, do they have relationship with each other?

I'm on v1.60 build 9617 by the way.

Much appreciate for your help, thank you!

Best,

5
General / Is there a way to put mask from sparse point cloud to image?
« on: October 06, 2020, 02:24:53 AM »
Hi Alexey,

Is there a way to draw mask for selected area from sparse point cloud / ortho to the photos, rather than draw mask each image with same mask? What I want to do is creating point cloud with very high desnity in some AOI, is that possible? Or is it possible to create point cloud with high density in some part and lower in not interested part to speed up?

Thank you!

6
Bug Reports / Possibly Wrong conversion in EPSG 5513
« on: August 25, 2020, 02:55:25 AM »
Hi Alexey,

I found some post before regarding EPSG 5513 / 5514 support, which is great, however when I am converting GCPs from WGS84 to EPSG:5513 and 5514 they show different sign (positive vs negative), but in EPSG.io they are the same: https://epsg.io/transform#s_srs=5513&t_srs=5514&x=-527358.6200000&y=-1140103.1800000

Which one is correct? By checking the proj4 string definition they are exactly the same in Metashape, so why there's a different sign for output? I know there's SW vs NE axis but not sure which source is correct.

Hope to hear from you soon.

Best,

7
General / Understanding confidence map of dense point cloud
« on: March 10, 2020, 06:41:52 AM »
Hi Friends,

Can anyone provide some info about the confidence map of Dense Point cloud? With the 0 to 255 level it works well with removing some noise, but I saw a weird image and interested to know how this confidence map related with image overlap, and how it is calculated for that pattern.

Best,

8
Bug Reports / proj4 definition not match with WKT EPSG 2056
« on: March 10, 2020, 06:07:22 AM »
Hello Alexey,

I found the EPSG: 2056 in Metashape returned different proj string to the WKT:
Proj4:

'+proj=omerc +lat_0=46.95240555555561 +lonc=7.439583333333329 +alpha=90 +gamma=90 +k_0=1 +x_0=2600000 +y_0=1200000 +ellps=bessel +units=m

WKT:
'PROJCS["CH1903+ / LV95",GEOGCS["CH1903+",DATUM["CH1903+",SPHEROID["Bessel 1841",6377397.155,299.1528128,AUTHORITY["EPSG","7004"]],TOWGS84[674.374,15.056,405.346,0,0,0,0],AUTHORITY["EPSG","6150"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9102"]],AUTHORITY["EPSG","4150"]],PROJECTION["Oblique_Mercator",AUTHORITY["EPSG","9815"]],PARAMETER["latitude_of_center",46.95240555555561],PARAMETER["longitude_of_center",7.439583333333329],PARAMETER["azimuth",90],PARAMETER["recitified_grid_angle",90],PARAMETER["scale_factor",1],PARAMETER["false_easting",2600000],PARAMETER["false_northing",1200000],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AUTHORITY["EPSG","2056"]]'

From http://epsg.io/2056 the projection in proj4 should be +proj=somerc rather than +proj=omerc. It's interesting that the conversion is correct, so I assume the conversion is not using proj4 string is it?

Thanks

9
Bug Reports / Different WKT definition to EPSG.io
« on: December 03, 2019, 05:28:32 AM »
Hello support,

I find that NAD83(CSRS) / BC Alberts EPSG:3153 in Agisoft has different WKT definition to http://epsg.io/3153.

In Metashape the toWGS84 defined as TOWGS84[-0.991,1.9072,0.5129,0.025789907519493,0.009650098960270401,0.011659943232342,0],

while in EPSG.io it is [0,0,0,0,0,0,0].

Is this a bug or different database for Agisoft referred to?

Thanks!

10
Hello everyone,

I have tried two different ways to project marker to the image plane, and I searched in the forum to find two ways:
(1)
marker = chunk.markers[0]
x0, y0 = marker.projections[camera].coord

(2)
camera.project(chunk.markers[0].position)

Method (1) returns Vector([2046.1069456339237, 1142.9500712869672]), while method 2 returns (2046.3900146484375, 1143.6800537109375).

Since both starts from estimated values, I am expecting they are the same, but they are different. Could someone explain why there's difference? Or if I should compare the integer but the Y has about 1 pixel difference...

Thanks a lot!

11
General / shift point clouds and all outputs
« on: December 02, 2019, 07:16:51 AM »
Dear support,

Is there any method to apply extra shift to the dense point cloud, and the following outputs continuing to work based on this shifted point cloud?

I found some thread mentioned to try project ortho photos to reloaded dense point cloud from external resource, is this possible to do so now?

Thanks!

12
Python and Java API / Help in localframe explain
« on: November 22, 2019, 06:48:04 AM »
Hi everyone,

Could anyone give some hints about the chunk.crs.localframe() matrix?
Hello claranine,

Code: [Select]
sourceGeogr = camera.reference.location #source values in geographic coordinate system
estGeogr = chunk.crs.project(chunk.transform.matrix.mulp(camera.center)) #estimated position in geographic coordinate system

sourceGeoc = chunk.crs.unproject(camera.reference.location) #measured values in geocentric coordinates
estimGeoc = chunk.transform.matrix.mulp(camera.center) #estimated coordinates in geocentric coordinates
local = chunk.crs.localframe(chunk.transform.matrix.mulp(camera.center)) #local LSE coordinates
error = local.mulv(estim - source)

As in this post why the error needs to use local.mulv to transform rather than directly use (estim - source)? Is this due to unit difference?

Thanks in advance!

13
Bug Reports / Image quality estimation not right for special blurry case
« on: November 19, 2019, 04:20:18 AM »
Hi Alexey,

I had one example of image with "blurry" due to out of focus, but the image quality estimator still gives me 0.76 image quality which says it is good. Is there any function to detect this kind of blurry?

Thanks a lot!
 

14
General / Is it possible to remove mask after imported it?
« on: July 19, 2019, 05:22:37 AM »
Hi friends,

Is there a button to remove imported mask? I haven't found it... Could anyone help? Or it can only be replaced by new mask file?


Thanks!

15
Python and Java API / Python script modify camera Yaw Pitch angles
« on: November 26, 2018, 10:19:16 AM »
Dear Support,

I had some searches in the forum but haven't found similar answers, so I post this new topic here.

What I want to achieve is, when I loaded the photos with orientation angles, is it possible to use python script to modify the angles rather than load a modified geotag file separately from GUI? For example an image Y/P/R is 17.2 / 0.5/0, and I want to change it from python to 180/89.5/0, is it possible to do from python api?

Thanks a lot!

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