3DTOPO's profile - activity

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2019-06-21 03:16:26 -0600	received badge	● Enthusiast
2019-06-19 19:06:58 -0600	asked a question	Compiling for iOS using Xcode 11.0 Beta 2 Compiling for iOS using Xcode 11.0 Beta 2 Hello, I am trying to take advantage of Xcode 11's new build iOS apps for the
2019-05-26 16:26:08 -0600	asked a question	Contours generating invalid points Contours generating invalid points I am generating contours the usual way: equalizeHist(inputImage, inputImage); Laplac
2017-05-07 16:40:08 -0600	commented question	Understanding Mat::at and implementing as a Shader Your missing the point - the code does exactly what I want. I am just trying to understand what Mat:at is doing so I can implement the same behavior as a shader. I know opencv isn't used for shaders.
2017-05-07 03:40:46 -0600	asked a question	Understanding Mat::at and implementing as a Shader Hello, In a prototype I am using mat:at to achieve a desired result. The problem is I need it to run in realtime on iOS and is currently too slow. I started writing a shader to achieve the same result and I have an image bitmap feed to the shader as a 1D array of bytes (RGBRGB...). This is roughly my code: //img is a Mat populated with an RGB image for (int r=1; r< (img.rows-1 * nativeByte); r++) { for (int c=1; c < (img.cols-1 * nativeByte); c++) { int outputOffsetNew = currentByte * ((img.cols * r) + c); //swapping stuff around is cool outputOffsetNew = effectTwoWithByte(outputOffsetNew, totalPixels); uchar newPixel = img.at<cv::Vec2b>(outputOffsetNew)[1]; img.at<cv::Vec3b>(r,c)[1] = newPixel; //replace the G pixel with the newPixel2 value } } int effectTwoWithByte(int byte, int totalPixels) { while (byte > (totalPixels) - 3) { byte *= 0.25f; if (byte < 0) { byte = 0; } } return byte; } Where is the source code for mat::at? Is it in mat.inl.hpp? If so, I am not sure which of the functions in there that it is calling. Can anyone explain what exactly mat:at is doing in my above code? If anyone could help explain what it is doing in pseudo code or C code I would very much appreciate it! For instance, if I had RGB values populated in a 1D uchar array, what column from a 1D uchar array would the above code use for newPixel?
2017-04-19 23:21:11 -0600	asked a question	cvCvtColor CFDataGetBytes Crash on iOS Hello, I have used the same code successfully with thousands of images, but I got what seems like a freak crash report. I don't know if the issue is reproducible because I have only received a crash report from a user for it. Any insight why this has worked for thousands of different images, but crashed on one would be greatly appreciated. This is my method that crashed: - (IplImage )CreateGrayIplImageFromUIImage:(UIImage )image { CGImageRef imageRef = image.CGImage; CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); IplImage iplimage = cvCreateImage(cvSize(image.size.width, image.size.height), IPL_DEPTH_8U, 4); CGContextRef contextRef = CGBitmapContextCreate(iplimage->imageData, iplimage->width, iplimage->height, iplimage->depth, iplimage->widthStep, colorSpace, kCGImageAlphaPremultipliedLast\|kCGBitmapByteOrderDefault); CGContextDrawImage(contextRef, CGRectMake(0, 0, image.size.width, image.size.height), imageRef); CGContextRelease(contextRef); CGColorSpaceRelease(colorSpace); IplImage ret = cvCreateImage(cvGetSize(iplimage), IPL_DEPTH_8U, 1); cvCvtColor(iplimage, ret, CV_RGBA2GRAY); cvReleaseImage(&iplimage); return ret; } The backtrace originates from cvCvtColor. This is a backtrace of the relevant threads: Thread #10. Crashed: com.apple.root.default-qos 0 libsystem_platform.dylib 0x185fd8dd0 _platform_memmove + 112 1 CoreFoundation 0x186e2679c CFDataGetBytes + 372 2 CoreFoundation 0x186e2679c CFDataGetBytes + 372 3 ImageIO 0x188d35c60 IIOImageRead::getCFDataBytesAtOffset(void, unsigned long, unsigned long) + 216 4 ImageIO 0x188d357b4 IIOImageRead::getBytesAtOffset(void, unsigned long, unsigned long) + 348 5 ImageIO 0x188bc893c read_fn2(png_struct_def, unsigned char, unsigned long) + 116 6 ImageIO 0x188d66fc0 png_crc_read + 48 7 ImageIO 0x188d6b178 png_read_IDAT_data + 308 8 ImageIO 0x188db46a0 _cg_png_read_row + 188 9 ImageIO 0x188bc87ac ___ZN13PNGReadPlugin17copyImageBlockSetEP7InfoRecP15CGImageProvider6CGRect6CGSizePK14__CFDictionary_block_invoke + 560 10 libdispatch.dylib 0x185dd6e44 _dispatch_client_callout2 + 16 11 libdispatch.dylib 0x185de9e38 _dispatch_apply_invoke + 164 12 libdispatch.dylib 0x185dd69a0 _dispatch_client_callout + 16 13 libdispatch.dylib 0x185de6bac _dispatch_root_queue_drain + 888 14 libdispatch.dylib 0x185de67d0 _dispatch_worker_thread3 + 124 15 libsystem_pthread.dylib 0x185fdf1d0 _pthread_wqthread + 1096 16 libsystem_pthread.dylib 0x185fded7c start_wqthread + 4 Thread #5. com.apple.root.default-qos 0 TDTPhotoLib 0x1008ce1d8 cvCvtColor + 61902 1 TDTPhotoLib 0x10064f588 -[UIImage(OpenCV) equalArea] (UIImage+OpenCV.mm:52) 2 MyApp 0x10015c098 TDTImageViewController.prepImage() -> () (TDTOptionsViewController.swift:783) 3 TDTPhotoLib 0x1006a997c TDTCropImageViewController.(renderAspectImage() -> ()).(closure #1) (TDTCropImageViewController.swift:455) 4 libdispatch.dylib 0x185dd69e0 _dispatch_call_block_and_release + 24 5 libdispatch.dylib 0x185dd69a0 _dispatch_client_callout + 16 6 libdispatch.dylib 0x185de50d4 _dispatch_queue_override_invoke + 644 7 libdispatch.dylib 0x185de6a50 _dispatch_root_queue_drain + 540 8 libdispatch.dylib 0x185de67d0 _dispatch_worker_thread3 + 124 9 libsystem_pthread.dylib 0x185fdf1d0 _pthread_wqthread + 1096 10 libsystem_pthread.dylib 0x185fded7c start_wqthread + 4 Thread #8. com.apple.root.default-qos 0 libsystem_kernel.dylib 0x185f18e64 __psynch_mutexwait + 8 1 libsystem_pthread.dylib 0x185fe4c5c _pthread_mutex_lock_wait + 96 2 ImageIO 0x188d35698 IIOImageRead::getBytesAtOffset(void, unsigned long, unsigned long) + 64 3 ImageIO 0x188bc893c read_fn2(png_struct_def, unsigned char, unsigned long) + 116 4 ImageIO 0x188d670f4 png_crc_error + 56 5 ImageIO 0x188d67048 png_crc_finish + 92 6 ImageIO 0x188d6b0d4 png_read_IDAT_data + 144 7 ImageIO 0x188db46a0 _cg_png_read_row + 188 8 ImageIO 0x188bc87ac ___ZN13PNGReadPlugin17copyImageBlockSetEP7InfoRecP15CGImageProvider6CGRect6CGSizePK14__CFDictionary_block_invoke + 560 9 libdispatch.dylib 0x185dd6e44 _dispatch_client_callout2 + 16 10 libdispatch.dylib 0x185deaa3c _dispatch_apply_invoke_and_wait + 164 11 libdispatch.dylib 0x185dea47c dispatch_apply_f + 828 12 ImageIO 0x188bc82b4 PNGReadPlugin::copyImageBlockSet(InfoRec, CGImageProvider, CGRect, CGSize, __CFDictionary const) + 3472 13 ImageIO 0x188bc5c50 PNGReadPlugin::CopyImageBlockSetProc(void, CGImageProvider, CGRect, CGSize, __CFDictionary const) + 192 14 ImageIO 0x188bcfbbc IIOImageProviderInfo::copyImageBlockSetWithOptions(CGImageProvider, CGRect, CGSize, __CFDictionary const) + 632 15 ImageIO 0x188bcda14 IIOImageProviderInfo::CopyImageBlockSetWithOptions(void, CGImageProvider, CGRect, CGSize, __CFDictionary const) + 340 16 CoreGraphics 0x1884efef4 img_blocks_create + 264 17 CoreGraphics 0x1884f7860 img_data_lock + 1872 18 CoreGraphics 0x1884f70b8 CGSImageDataLock + 176 19 CoreGraphics 0x1883171c0 ripc_AcquireImage + 756 20 ... (more)